# Software Engineering Curriculum

> 259 concepts across 19 software engineering tracks, with 26 sequenced roadmaps, active drills, review prompts, and build artifacts.

Canonical: https://learn.significanthobbies.com/curriculum/

# SWE Prep Curriculum Catalog

A public, JavaScript-free index of 259 concepts across
19 tracks and 26 sequenced roadmaps.
The active learning loop is Concept → Drill → Build → Review → Apply.

- Human curriculum hub: https://learn.significanthobbies.com/curriculum/
- System-design case library: https://learn.significanthobbies.com/system-design/
- Structured JSON catalog: https://learn.significanthobbies.com/curriculum/catalog.json
- Interactive learning app: https://learn.significanthobbies.com/learn

# Roadmaps

- [9-Day Reset](https://learn.significanthobbies.com/curriculum/roadmaps/reset-9-day) (9d) — Rebuild learning momentum by taking one concept all the way to a shipped artifact.
- [30-Day Retrieval Basics](https://learn.significanthobbies.com/curriculum/roadmaps/retrieval-30-day) (30d) — Build a solid foundation in both lexical and vector retrieval, ending with hybrid search.
- [90-Day AI Search & Infrastructure](https://learn.significanthobbies.com/curriculum/roadmaps/ai-search-infra-90-day) (90d) — Build a strong retrieval, vector, AI-systems, and storage foundation through HighSignal and Codevetter.
- [12-Month Advanced AI Infrastructure](https://learn.significanthobbies.com/curriculum/roadmaps/ai-infra-12-month) (12mo) — Reach the depth to design and reason about systems like Turbopuffer, and ship them through HighSignal and Codevetter.
- [Disk-First Databases & RAM](https://learn.significanthobbies.com/curriculum/roadmaps/db-disk-first) (12mo) — Build a mechanism-first mental model of how disk-based DBs spend RAM, and why.
- [Runtime — what every runtime has to do](https://learn.significanthobbies.com/curriculum/roadmaps/runtime) (12mo) — Build one cross-cutting mental model for V8, JVM, Go, BEAM, .NET CLR, vLLM, SGLang, Cloudflare Workers, and wasmtime.
- [The Software Engineering Landscape (2026)](https://learn.significanthobbies.com/curriculum/roadmaps/swe-landscape) (12mo) — Get a working mental model of every major systems-software domain — LLMs, DBs, streaming, game engines, containers, browsers, compilers, OS, networking, distributed, build, crypto.
- [LLD Practice](https://learn.significanthobbies.com/curriculum/roadmaps/lld-practice) (30d) — Build the design-rounds muscle: model state and behaviour explicitly, justify every class boundary.
- [HLD Practice](https://learn.significanthobbies.com/curriculum/roadmaps/hld-practice) (30d) — Be able to design X — feed, chat, ride-hailing, search — under a 45-minute clock with credible numbers.
- [DSA Practice](https://learn.significanthobbies.com/curriculum/roadmaps/dsa-practice) (30d) — Solve canonical patterns from scratch — no references, explain the invariant, add one edge-case test.
- [30-Day Math Rating Climb](https://learn.significanthobbies.com/curriculum/roadmaps/math-rating-climb-30d) (30d) — Raise your per-roadmap ELO by climbing from linear algebra through statistics to calculus — each week unlocks harder drills at your edge.
- [30-Day Probability & Statistics](https://learn.significanthobbies.com/curriculum/roadmaps/prob-stats-30d) (30d) — Active probability & statistics — solve, derive, implement. No passive video watching as a substitute for problems.
- [12-Week Active Math Stack](https://learn.significanthobbies.com/curriculum/roadmaps/math-stack-12w) (12mo) — Math → AI systems → distributed/data → quant tools. Active only: solve, derive, implement, simulate — never aesthetic consumption.
- [Behavioral Practice](https://learn.significanthobbies.com/curriculum/roadmaps/behavioral-practice) (30d) — Have a STAR-shaped story for every Amazon-style leadership principle, with one self-aware "what I would do differently".
- [12-Week Systems Foundations](https://learn.significanthobbies.com/curriculum/roadmaps/systems-foundations-12w) (90d) — Build a mechanism-first model from hardware and kernels through runtimes, networks, performance, and isolation.
- [12-Week Infrastructure & Platforms](https://learn.significanthobbies.com/curriculum/roadmaps/infrastructure-platforms-12w) (90d) — Design and operate a reproducible, observable, fault-tolerant platform for untrusted workloads.
- [12-Week Distributed Systems](https://learn.significanthobbies.com/curriculum/roadmaps/distributed-systems-12w) (90d) — Reason about coordination, data placement, logs, durable workflows, consistency, and recovery under partial failure.
- [12-Week AI Models & Training](https://learn.significanthobbies.com/curriculum/roadmaps/ai-models-training-12w) (90d) — Move from transformer foundations through pre-training, fine-tuning, post-training, compression, and evaluation.
- [12-Week Inference & Serving](https://learn.significanthobbies.com/curriculum/roadmaps/inference-serving-12w) (90d) — Build a production mental model for inference engines, memory, kernels, routing, hardware, and serving economics.
- [12-Week Agent Systems](https://learn.significanthobbies.com/curriculum/roadmaps/agent-systems-12w) (90d) — Engineer useful agents with bounded loops, tools, memory, protocols, durability, permissions, and long-running control.
- [12-Week Evaluation & AI Reliability](https://learn.significanthobbies.com/curriculum/roadmaps/ai-reliability-12w) (90d) — Build an evidence-backed evaluation and observability system for models, tools, and agents.
- [12-Week Developer Tools & Code Intelligence](https://learn.significanthobbies.com/curriculum/roadmaps/developer-tools-12w) (90d) — Build repository-aware tools that analyze, test, review, debug, and safely remediate code.
- [12-Week Application Engineering](https://learn.significanthobbies.com/curriculum/roadmaps/application-engineering-12w) (90d) — Turn backend, client, UX, real-time, interactive, analytics, and distribution skills into one complete product.
- [12-Week Multimodal & Spatial Computing](https://learn.significanthobbies.com/curriculum/roadmaps/multimodal-spatial-12w) (90d) — Connect vision, audio, generation, on-device intelligence, robotics, spatial interfaces, and HCI.
- [Trace a Tensor](https://learn.significanthobbies.com/curriculum/roadmaps/trace-a-tensor) (30d) — Follow one model workload from representation and gradients to memory, kernels, scheduling, and serving economics.
- [Harness Engineering](https://learn.significanthobbies.com/curriculum/roadmaps/harness-engineering) (30d) — Design, build, verify, and evaluate the environment around a coding agent so it can make reliable progress across bounded and long-running tasks.

# System-design interview cases

- [Design LLM inference at 10K RPS](https://learn.significanthobbies.com/system-design/llm-inference-10k-rps) — Design a production LLM inference service that sustains 10,000 requests per second. Explain how you turn that headline into capacity, architecture, overload, and reliability decisions.
- [Design production RAG](https://learn.significanthobbies.com/mock?prompt=production-rag&from=guide) — Design retrieval-augmented generation over a large, frequently changing document corpus with permissions and citations.
- [Design a multi-tenant LLM gateway](https://learn.significanthobbies.com/mock?prompt=multi-tenant-llm-gateway&from=guide) — Design an API gateway in front of multiple LLM models and providers for thousands of tenants.
- [Design real-time recommendations](https://learn.significanthobbies.com/mock?prompt=real-time-recommendations&from=guide) — Design a real-time recommendation service for a large consumer application.
- [Design a URL shortener](https://learn.significanthobbies.com/mock?prompt=url-shortener&from=guide) — Design a global URL-shortening service with custom aliases, analytics, expiration, and abuse controls.
- [Design a distributed rate limiter](https://learn.significanthobbies.com/mock?prompt=distributed-rate-limiter&from=guide) — Design a global, multi-tenant rate limiter for an API gateway with burst allowances and regional enforcement.
- [Design real-time chat](https://learn.significanthobbies.com/mock?prompt=real-time-chat&from=guide) — Design real-time one-to-one and group chat for 50 million daily active users.
- [Design a ranked news feed](https://learn.significanthobbies.com/mock?prompt=ranked-news-feed&from=guide) — Design a ranked home feed for 100 million users with celebrity accounts, freshness, and moderation.
- [Design a video streaming platform](https://learn.significanthobbies.com/system-design/video-streaming-platform) — Design an on-demand video platform for creator uploads and global playback. Focus on the reusable upload, transcode, package, authorize, and CDN-delivery pattern rather than recommendations.
- [Design a photo-sharing platform](https://learn.significanthobbies.com/mock?prompt=photo-sharing-platform&from=guide) — Design an Instagram-like photo-sharing service with uploads, transformations, privacy, feeds, likes, and safe deletion. Focus on media and social-delivery boundaries.
- [Design a collaborative document editor](https://learn.significanthobbies.com/mock?prompt=collaborative-document-editor&from=guide) — Design a Google Docs-like editor with real-time multi-user edits, offline work, presence, history, permissions, and deterministic convergence.
- [Design a notification delivery service](https://learn.significanthobbies.com/system-design/notification-delivery-service) — Design push, email, SMS, and in-app notification delivery with user preferences, priorities, quotas, retries, provider failure, and duplicate control.
- [Design a web crawler](https://learn.significanthobbies.com/system-design/web-crawler) — Design a web-scale crawler that discovers, fetches, deduplicates, stores, and recrawls useful pages while obeying robots policy and host politeness.
- [Design a distributed cache](https://learn.significanthobbies.com/mock?prompt=distributed-cache&from=guide) — Design a low-latency distributed cache with partitioning, replication, TTL, eviction, invalidation, node failure, hot keys, and stampede protection.
- [Design search autocomplete](https://learn.significanthobbies.com/mock?prompt=search-autocomplete&from=guide) — Design typeahead suggestions for a large search product with prefix lookup, ranking, trends, personalization, freshness, moderation, and low latency.
- [Design cloud file storage](https://learn.significanthobbies.com/system-design/cloud-file-storage) — Design Dropbox or Google Drive-style file synchronization with resumable uploads, folders, sharing, versions, offline conflicts, durability, and efficient transfer.
- [Design a distributed key-value store](https://learn.significanthobbies.com/mock?prompt=distributed-key-value-store&from=guide) — Design a Dynamo-style distributed key-value store with partitioning, replication, tunable consistency, durability, rebalancing, repair, and compaction.
- [Design a ride-sharing platform](https://learn.significanthobbies.com/system-design/ride-sharing-platform) — Design an Uber or Lyft-style marketplace with driver locations, nearby matching, dispatch offers, atomic trip assignment, live trip state, ETA, and regional spikes.
- [Design a ticket-booking platform](https://learn.significanthobbies.com/system-design/ticket-booking-platform) — Design Ticketmaster-style reserved-seat booking with event browse, a virtual waiting room, expiring holds, payments, oversell prevention, bots, and flash crowds.
- [Design a payment-processing system](https://learn.significanthobbies.com/mock?prompt=payment-processing-system&from=guide) — Design a payment system with authorization, capture, refunds, idempotency, webhooks, an auditable ledger, processor timeouts, reconciliation, and fraud controls.
- [Design a distributed unique ID generator](https://learn.significanthobbies.com/mock?prompt=distributed-unique-id-generator&from=guide) — Design a service that issues globally unique, roughly time-sortable 64-bit IDs to thousands of application servers across regions without a database round trip per ID.
- [Design a proximity search service](https://learn.significanthobbies.com/mock?prompt=proximity-search-service&from=guide) — Design a service that returns open businesses within a radius, filtered by category and ranked by distance, for a global consumer application.
- [Design a nearby friends service](https://learn.significanthobbies.com/mock?prompt=nearby-friends-service&from=guide) — Design an opt-in feature that shows which friends are nearby and updates within seconds as people move, while making privacy and battery cost first-class constraints.
- [Design a maps and routing platform](https://learn.significanthobbies.com/mock?prompt=maps-routing-platform&from=guide) — Design a driving-directions service that returns routes and ETAs across a continent, incorporates live traffic, and can serve map tiles separately from route computation.
- [Design a distributed message queue](https://learn.significanthobbies.com/mock?prompt=distributed-message-queue&from=guide) — Design a multi-tenant distributed queue for asynchronous jobs and event streams with durable retention, consumer groups, backpressure, and at-least-once delivery.
- [Design a metrics monitoring platform](https://learn.significanthobbies.com/mock?prompt=metrics-monitoring-platform&from=guide) — Design a multi-tenant metrics platform that ingests counters, gauges, and histograms, supports dashboard queries and recording rules, and evaluates reliable alerts.
- [Design an ad click aggregation system](https://learn.significanthobbies.com/mock?prompt=ad-click-aggregation-system&from=guide) — Design an ad click pipeline that powers near-real-time campaign dashboards and produces auditable daily billing aggregates despite duplicates, retries, bots, and late events.
- [Design a hotel reservation system](https://learn.significanthobbies.com/mock?prompt=hotel-reservation-system&from=guide) — Design a hotel booking platform that searches room availability and prevents overselling across multi-night stays, retries, payment delays, and expiring holds.
- [Design a distributed email service](https://learn.significanthobbies.com/mock?prompt=distributed-email-service&from=guide) — Design a transactional email platform that accepts API requests, renders templates, delivers through SMTP, handles retries and bounces, and protects sender reputation.
- [Design an object storage service](https://learn.significanthobbies.com/mock?prompt=object-storage-service&from=guide) — Design an S3-like object storage service with buckets, immutable object versions, multipart uploads, ranged reads, checksums, lifecycle policies, and regional durability.
- [Design a real-time gaming leaderboard](https://learn.significanthobbies.com/mock?prompt=gaming-leaderboard&from=guide) — Design a leaderboard for a global game with seasonal, regional, and friends-only rankings, real-time score updates, anti-cheat review, and stable end-of-season results.
- [Design a digital wallet](https://learn.significanthobbies.com/mock?prompt=digital-wallet-system&from=guide) — Design a digital wallet that supports deposits, peer-to-peer transfers, merchant payments, refunds, and withdrawals while maintaining auditable balances across retries and external settlement.
- [Design a stock exchange](https://learn.significanthobbies.com/mock?prompt=stock-exchange&from=guide) — Design the core of a stock exchange that accepts limit and market orders, matches by price-time priority, publishes market data, and recovers without reordering or duplicating trades.

# Tracks and concepts

## Search & IR

Lexical retrieval beyond embeddings: tokenization, inverted indexes, BM25, ranking, hybrid search, and search evaluation.

- Public page: https://learn.significanthobbies.com/curriculum/tracks/search-ir
- Concepts: 13
- Roadmaps: 4

- [Tokenization](https://learn.significanthobbies.com/curriculum/concepts/tokenization) — Splitting text into terms: lowercasing, stemming, stop words, n-grams.
- [Inverted Index](https://learn.significanthobbies.com/curriculum/concepts/inverted-index) — Term → posting list mapping that powers fast keyword lookup.
- [TF-IDF](https://learn.significanthobbies.com/curriculum/concepts/tf-idf) — Term frequency × inverse document frequency weighting for relevance.
- [BM25](https://learn.significanthobbies.com/curriculum/concepts/bm25) — The standard lexical ranking function: TF saturation + IDF + length normalization.
- [Ranking Metrics](https://learn.significanthobbies.com/curriculum/concepts/ranking-metrics) — Precision, recall, MRR, and nDCG for measuring retrieval quality.
- [Search Evals](https://learn.significanthobbies.com/curriculum/concepts/search-evals) — Building a labelled query set and harness to compare retrieval approaches.
- [Hybrid Search](https://learn.significanthobbies.com/curriculum/concepts/hybrid-search) — Fusing lexical (BM25) and vector retrieval, usually via reciprocal rank fusion.
- [Reranking](https://learn.significanthobbies.com/curriculum/concepts/reranking) — A second-stage cross-encoder pass that reorders the top-k candidates.
- [Query Rewriting](https://learn.significanthobbies.com/curriculum/concepts/query-rewriting) — Expanding, correcting, and normalizing queries before retrieval.
- [Search Systems](https://learn.significanthobbies.com/curriculum/concepts/search-discovery) — Inverted index, ranking, autocomplete at scale.
- [Top-k Pruning (WAND)](https://learn.significanthobbies.com/curriculum/concepts/top-k-pruning) — WAND, MaxScore, and block-max — skipping documents that cannot reach the top k.
- [Learning to Rank](https://learn.significanthobbies.com/curriculum/concepts/learning-to-rank) — Pointwise, pairwise, and listwise objectives — and why the metric you care about is not differentiable.
- [Click Models & Position Bias](https://learn.significanthobbies.com/curriculum/concepts/click-models) — Why clicks are not relevance labels, and how to debias implicit feedback.

## Mathematics

Active math only: solve, derive, implement, simulate — never aesthetic consumption. Stack: probability & statistics → linear algebra → optimization → quant bridge. No artifact, no learning.

- Public page: https://learn.significanthobbies.com/curriculum/tracks/mathematics
- Concepts: 30
- Roadmaps: 3

- [Vectors & Vector Spaces](https://learn.significanthobbies.com/curriculum/concepts/vectors-and-spaces) — Vectors as ordered lists, dot products, norms, orthogonality, and the geometric picture of n-dimensional space.
- [Matrices & Linear Transformations](https://learn.significanthobbies.com/curriculum/concepts/matrices-and-transformations) — Matrix multiplication as composing linear maps: rotation, scaling, projection, and change of basis.
- [Eigenvalues & Matrix Decomposition](https://learn.significanthobbies.com/curriculum/concepts/eigenvalues-decomposition) — Eigenvectors as directions preserved by a transformation; eigenvalues as stretch factors; SVD as the universal factorization.
- [Probability Fundamentals](https://learn.significanthobbies.com/curriculum/concepts/probability-fundamentals) — Sample spaces, conditional probability, independence, and Bayes' rule for updating beliefs.
- [Random Variables & Distributions](https://learn.significanthobbies.com/curriculum/concepts/random-variables) — Discrete and continuous distributions, expectation, variance, and the law of large numbers.
- [Descriptive Statistics](https://learn.significanthobbies.com/curriculum/concepts/descriptive-statistics) — Summarizing data: mean, median, variance, correlation, and when each summary lies.
- [Estimation & Confidence Intervals](https://learn.significanthobbies.com/curriculum/concepts/estimation-confidence) — Point estimates, standard error, confidence intervals, and what '95% confident' actually means.
- [Hypothesis Testing](https://learn.significanthobbies.com/curriculum/concepts/hypothesis-testing) — Null and alternative hypotheses, p-values, significance, power, and Type I/II errors.
- [Linear Regression](https://learn.significanthobbies.com/curriculum/concepts/regression-basics) — Fitting a line (or hyperplane) by least squares; residuals, R², and the geometry of projection.
- [Derivatives & Gradients](https://learn.significanthobbies.com/curriculum/concepts/derivatives-and-gradients) — Partial derivatives, the gradient vector, and reading a loss surface for descent direction.
- [Multivariable Optimization](https://learn.significanthobbies.com/curriculum/concepts/multivariable-optimization) — Convexity, critical points, constrained optimization, and why SGD works on non-convex losses anyway.
- [Information & Entropy](https://learn.significanthobbies.com/curriculum/concepts/information-entropy) — Entropy as surprise, cross-entropy as a loss, KL divergence as a distributional distance.
- [Classical Distributions](https://learn.significanthobbies.com/curriculum/concepts/classical-distributions) — Bernoulli, Binomial, Poisson, Normal, and Exponential — when each models the world and what to expect from them.
- [Sampling & the Central Limit Theorem](https://learn.significanthobbies.com/curriculum/concepts/sampling-and-clt) — Sampling distributions, standard error of the mean, and why averages become Normal as n grows.
- [A/B Testing for Engineers](https://learn.significanthobbies.com/curriculum/concepts/ab-testing-engineering) — Sample size, statistical power, practical significance, SRM checks, and multiple-comparison traps in product experiments.
- [Bayesian Inference](https://learn.significanthobbies.com/curriculum/concepts/bayesian-inference) — Priors, posteriors, credible intervals, and when Bayesian updating beats frequentist tests.
- [Maximum Likelihood Estimation](https://learn.significanthobbies.com/curriculum/concepts/maximum-likelihood) — Choosing parameters that make the observed data most probable; log-likelihood; connection to cross-entropy loss.
- [Covariance & Correlation](https://learn.significanthobbies.com/curriculum/concepts/covariance-correlation) — Covariance measures co-movement; correlation normalizes to [−1, 1]. Foundation for regression, PCA, and portfolio risk.
- [Bias, Variance & Overfitting](https://learn.significanthobbies.com/curriculum/concepts/bias-variance-overfitting) — Underfitting vs memorizing noise; why in-sample greatness lies.
- [Rank, Basis & Subspaces](https://learn.significanthobbies.com/curriculum/concepts/matrix-rank-basis) — Column space, rank, independence — why matrices are often low-rank in practice.
- [PCA & Projection](https://learn.significanthobbies.com/curriculum/concepts/pca-projection) — Principal components as variance-maximizing orthogonal directions; projection as subspace approximation.
- [Returns & Volatility](https://learn.significanthobbies.com/curriculum/concepts/returns-volatility) — Simple/log returns, realized volatility, annualization — basic quant units.
- [Stationarity & Autocorrelation](https://learn.significanthobbies.com/curriculum/concepts/stationarity-autocorrelation) — When series statistics are stable; memory in lags; noise vs signal.
- [Random Walks & Markov Chains](https://learn.significanthobbies.com/curriculum/concepts/random-walks-markov) — Markov property, random walks, transition matrices — generative story behind market efficiency intuition.
- [Sharpe, Drawdown & Portfolio Risk](https://learn.significanthobbies.com/curriculum/concepts/portfolio-risk-metrics) — Sharpe, max drawdown, correlation matrices — risk-adjusted comparison.
- [Momentum Backtest Discipline](https://learn.significanthobbies.com/curriculum/concepts/momentum-backtest) — Momentum rules, SPY/QQQ benchmarks, holdout honesty — why most backtests lie.
- [Queueing Theory](https://learn.significanthobbies.com/curriculum/concepts/queueing-theory) — Little's law and the utilisation curve — why latency explodes before a system runs out of capacity.
- [Curse of Dimensionality](https://learn.significanthobbies.com/curriculum/concepts/curse-of-dimensionality) — Why distances concentrate in high dimensions, and what that does to nearest-neighbour search.
- [Combinatorics](https://learn.significanthobbies.com/curriculum/concepts/combinatorics) — Counting without enumerating — permutations, combinations, inclusion-exclusion, pigeonhole.
- [Numerical Stability](https://learn.significanthobbies.com/curriculum/concepts/numerical-stability) — Floating point, catastrophic cancellation, and the log-sum-exp trick.

## Vector DB & ANN

Vector search engines: similarity, top-k, brute force, HNSW, IVF, quantization, metadata filtering, and recall/latency tradeoffs.

- Public page: https://learn.significanthobbies.com/curriculum/tracks/vector-db
- Concepts: 12
- Roadmaps: 3

- [Embeddings](https://learn.significanthobbies.com/curriculum/concepts/embeddings) — Mapping text/images into dense vectors where distance encodes meaning.
- [Vector Similarity](https://learn.significanthobbies.com/curriculum/concepts/vector-similarity) — Cosine, dot product, and L2 distance — how to score vector closeness.
- [Top-k Vector Search](https://learn.significanthobbies.com/curriculum/concepts/topk-vector-search) — Returning the k nearest vectors to a query, exact or approximate.
- [Brute-Force Vector DB](https://learn.significanthobbies.com/curriculum/concepts/brute-force-vector-db) — Exact nearest-neighbour search by scanning every vector — the correctness baseline.
- [HNSW](https://learn.significanthobbies.com/curriculum/concepts/hnsw) — Hierarchical Navigable Small World graphs — the dominant ANN index.
- [IVF (Inverted File)](https://learn.significanthobbies.com/curriculum/concepts/ivf) — Cluster vectors with k-means, then search only the nearest cells (nprobe).
- [Product Quantization](https://learn.significanthobbies.com/curriculum/concepts/product-quantization) — Compress vectors into sub-space codebooks for tiny memory footprint.
- [Metadata Filtering](https://learn.significanthobbies.com/curriculum/concepts/metadata-filtering) — Combining vector search with structured predicates (tenant, date, tags).
- [Recall / Latency Tradeoffs](https://learn.significanthobbies.com/curriculum/concepts/recall-latency-tradeoffs) — Reading recall-vs-latency curves to choose ANN parameters.
- [Scalar & Binary Quantization](https://learn.significanthobbies.com/curriculum/concepts/vector-quantization) — Shrinking vectors to int8 or single bits, and rescoring to recover the lost precision.
- [Disk-Based ANN](https://learn.significanthobbies.com/curriculum/concepts/disk-based-ann) — DiskANN and SPANN — serving vector indexes that do not fit in memory.
- [Index Updates & Tombstones](https://learn.significanthobbies.com/curriculum/concepts/index-updates-tombstones) — Deleting and updating vectors in a graph index without rebuilding it.

## AI Systems

Practical AI engineering: LLM apps, RAG, chunking, tool calling, agents, evals, and model/transformer foundations.

- Public page: https://learn.significanthobbies.com/curriculum/tracks/ai-systems
- Concepts: 32
- Roadmaps: 6

- [RAG](https://learn.significanthobbies.com/curriculum/concepts/rag) — Retrieval-Augmented Generation: ground an LLM answer in retrieved context.
- [Chunking](https://learn.significanthobbies.com/curriculum/concepts/chunking) — Splitting documents into retrievable units that preserve meaning.
- [Context Packing](https://learn.significanthobbies.com/curriculum/concepts/context-packing) — Ordering and budgeting retrieved context within the model's window.
- [Structured Outputs](https://learn.significanthobbies.com/curriculum/concepts/structured-outputs) — Forcing LLM output into a validated JSON schema.
- [Tool Calling](https://learn.significanthobbies.com/curriculum/concepts/tool-calling) — Letting an LLM invoke functions/APIs via structured calls.
- [Agent Loops](https://learn.significanthobbies.com/curriculum/concepts/agent-loops) — The plan → act → observe loop, with memory and stopping conditions.
- [Model Routing](https://learn.significanthobbies.com/curriculum/concepts/model-routing) — Sending each request to the cheapest model that can handle it.
- [Prompt & Version Logging](https://learn.significanthobbies.com/curriculum/concepts/prompt-versioning) — Treating prompts as versioned artifacts with logged inputs/outputs.
- [LLM Evals](https://learn.significanthobbies.com/curriculum/concepts/llm-evals) — Measuring LLM output quality with datasets, graders, and LLM-as-judge.
- [ML Math Foundations](https://learn.significanthobbies.com/curriculum/concepts/ml-math) — Vectors, matrices, dot products, matmul, shapes.
- [Gradient Descent](https://learn.significanthobbies.com/curriculum/concepts/ml-gradient-descent) — Loss surfaces, learning rate, SGD steps.
- [Backpropagation](https://learn.significanthobbies.com/curriculum/concepts/ml-backprop) — Chain rule, autograd, forward/backward passes.
- [Softmax & Cross-Entropy](https://learn.significanthobbies.com/curriculum/concepts/ml-softmax-xent) — Logits to probabilities, negative log-likelihood loss.
- [AdamW Optimizer](https://learn.significanthobbies.com/curriculum/concepts/ml-adamw) — Moments, weight decay, gradient clipping.
- [Tokenization (LLM)](https://learn.significanthobbies.com/curriculum/concepts/ml-tokenization) — Byte-level, char-level, BPE, vocab design.
- [Language Modeling](https://learn.significanthobbies.com/curriculum/concepts/ml-language-modeling) — Next-token prediction, context windows, perplexity.
- [Sampling & Decoding](https://learn.significanthobbies.com/curriculum/concepts/ml-sampling) — Temperature, top-k, greedy decoding.
- [Embeddings (Transformer)](https://learn.significanthobbies.com/curriculum/concepts/ml-embeddings) — Token & position embeddings, tied weights.
- [Self-Attention](https://learn.significanthobbies.com/curriculum/concepts/ml-self-attention) — Q/K/V, scaled dot-product, causal masking.
- [Multi-Head Attention](https://learn.significanthobbies.com/curriculum/concepts/ml-multi-head) — Parallel heads, head_dim split, output projection.
- [Transformer Block](https://learn.significanthobbies.com/curriculum/concepts/ml-transformer-block) — Pre-LayerNorm, residuals, MLP, GELU.
- [Training & Debugging](https://learn.significanthobbies.com/curriculum/concepts/ml-training) — Init, NaNs, overfit tests, gradient checks.
- [Checkpointing](https://learn.significanthobbies.com/curriculum/concepts/ml-checkpointing) — Weights + optimizer state, resume, dataset manifests.
- [LoRA & PEFT](https://learn.significanthobbies.com/curriculum/concepts/ml-lora) — Frozen base, low-rank adapters, rank/alpha.
- [RL Alignment (GRPO & Policy Gradient)](https://learn.significanthobbies.com/curriculum/concepts/ml-rl-alignment) — Policy gradient, advantages, GRPO/CISPO, on- vs off-policy RLHF.
- [Training Data Engineering](https://learn.significanthobbies.com/curriculum/concepts/ml-data-engineering) — Cleaning, dedup, JSONL tasks, memorization tests.
- [Browser ML Runtime](https://learn.significanthobbies.com/curriculum/concepts/ml-browser-runtime) — Web Workers, WASM, OPFS, TypedArrays.
- [WebGPU Compute](https://learn.significanthobbies.com/curriculum/concepts/ml-webgpu) — WGSL, compute kernels, matmul, CPU parity.
- [Model Evaluation](https://learn.significanthobbies.com/curriculum/concepts/ml-evaluation) — Held-out loss, baselines, hallucination, leakage.
- [Model Pre-training](https://learn.significanthobbies.com/curriculum/concepts/ml-pretraining) — Data mixtures, next-token objectives, scaling laws, distributed training, checkpoints, and training stability.
- [Model Quantization](https://learn.significanthobbies.com/curriculum/concepts/model-quantization) — Post-training and quantization-aware methods, integer and low-bit formats, calibration, kernels, and quality trade-offs.
- [Open-Weight Models](https://learn.significanthobbies.com/curriculum/concepts/open-weight-models) — Model cards, licenses, weights, tokenizers, chat templates, adapters, provenance, and reproducible packaging.

## Backend

Production backend strength: HTTP, API design, auth, rate limiting, idempotency, queues, jobs, caching, and observability.

- Public page: https://learn.significanthobbies.com/curriculum/tracks/backend
- Concepts: 16
- Roadmaps: 4

- [HTTP Lifecycle](https://learn.significanthobbies.com/curriculum/concepts/http-lifecycle) — DNS → TCP/TLS → request → response: status codes, headers, keep-alive.
- [API Keys](https://learn.significanthobbies.com/curriculum/concepts/api-keys) — Issuing, hashing, scoping, and rotating keys for machine clients.
- [Rate Limiting](https://learn.significanthobbies.com/curriculum/concepts/rate-limiting) — Token bucket, leaky bucket, sliding window.
- [Idempotency](https://learn.significanthobbies.com/curriculum/concepts/idempotency) — Idempotency keys and dedup windows for safe retries of mutations.
- [Retries & DLQ](https://learn.significanthobbies.com/curriculum/concepts/retries-dlq) — Backoff + jitter, poison messages, dead-letter queues.
- [Webhooks](https://learn.significanthobbies.com/curriculum/concepts/webhooks) — Outbound event delivery: signing, retries, idempotent receivers.
- [Background Jobs](https://learn.significanthobbies.com/curriculum/concepts/background-jobs) — Offloading slow work to workers: scheduling, concurrency, visibility.
- [Caching](https://learn.significanthobbies.com/curriculum/concepts/caching) — Cache-aside, write-through, eviction policies.
- [Message Queues](https://learn.significanthobbies.com/curriculum/concepts/message-queues) — Kafka, SQS, exactly-once vs at-least-once.
- [Observability](https://learn.significanthobbies.com/curriculum/concepts/monitoring-analytics) — Metrics, logs, traces, context propagation, semantic conventions, sampling, collectors, and telemetry pipelines.
- [API Design](https://learn.significanthobbies.com/curriculum/concepts/api-design) — REST, gRPC, versioning, pagination.
- [Auth Systems](https://learn.significanthobbies.com/curriculum/concepts/auth-systems) — OAuth2, JWT, session, RBAC.
- [Payments](https://learn.significanthobbies.com/curriculum/concepts/ecommerce-payments) — Idempotency, sagas, double-entry.
- [Retries & Circuit Breakers](https://learn.significanthobbies.com/curriculum/concepts/retries-and-circuit-breakers) — Backoff, jitter, budgets, and breakers — retrying without turning a blip into an outage.
- [Web Security Basics](https://learn.significanthobbies.com/curriculum/concepts/web-security-basics) — XSS, CSRF, SQL injection, and CORS — the injection and confused-deputy bugs that keep recurring.
- [Pagination](https://learn.significanthobbies.com/curriculum/concepts/pagination) — Offset versus cursor pagination, stable ordering, and why deep pages get expensive.

## Databases & Storage

Storage foundations for Turbopuffer-class systems: B-trees, LSM trees, WAL, compaction, partitioning, replication, object storage.

- Public page: https://learn.significanthobbies.com/curriculum/tracks/databases
- Concepts: 18
- Roadmaps: 4

- [B-Tree](https://learn.significanthobbies.com/curriculum/concepts/b-tree) — The balanced, disk-friendly tree behind most relational indexes.
- [LSM Tree](https://learn.significanthobbies.com/curriculum/concepts/lsm-tree) — Log-structured merge tree: write-optimized storage via sorted runs.
- [Write-Ahead Log](https://learn.significanthobbies.com/curriculum/concepts/wal) — Append-only durability log written before the data pages.
- [Compaction](https://learn.significanthobbies.com/curriculum/concepts/compaction) — Merging sorted runs to reclaim space and bound read amplification.
- [Object Storage](https://learn.significanthobbies.com/curriculum/concepts/object-storage) — S3-style blob storage: cheap, durable, high-latency, immutable objects.
- [Columnar Storage](https://learn.significanthobbies.com/curriculum/concepts/columnar-storage) — Column-oriented layout for analytics: compression and vectorized scans.
- [Secondary Indexes](https://learn.significanthobbies.com/curriculum/concepts/secondary-index) — Extra indexes for non-primary-key lookups, and what they cost on writes.
- [Storage Engines](https://learn.significanthobbies.com/curriculum/concepts/storage-retrieval) — B-tree vs LSM, indexing, WAL.
- [Sharding](https://learn.significanthobbies.com/curriculum/concepts/sharding) — Range/hash/geo partitioning.
- [Replication](https://learn.significanthobbies.com/curriculum/concepts/replication) — Leader-follower, multi-leader, quorum.
- [CAP & Consistency Models](https://learn.significanthobbies.com/curriculum/concepts/cap-theorem) — Strong/eventual/causal, PACELC.
- [Transaction Processing](https://learn.significanthobbies.com/curriculum/concepts/transaction-processing) — ACID, MVCC, isolation anomalies, locking, optimistic control, serializability, commit, and recovery.
- [Query Execution & Optimization](https://learn.significanthobbies.com/curriculum/concepts/query-execution-optimization) — Logical and physical plans, cardinality estimation, join ordering, indexes, vectorized execution, and spilling.
- [Data Warehouses & Lakehouses](https://learn.significanthobbies.com/curriculum/concepts/warehouses-lakehouses) — Columnar files, table formats, storage-compute separation, batch execution, metadata, governance, and lakehouse architecture.
- [Isolation Levels & MVCC](https://learn.significanthobbies.com/curriculum/concepts/isolation-levels) — What each isolation level actually prevents, and how MVCC delivers snapshots without read locks.
- [Join Algorithms](https://learn.significanthobbies.com/curriculum/concepts/join-algorithms) — Nested-loop, hash, and merge joins — and why cardinality estimates decide which one you get.
- [Normalization](https://learn.significanthobbies.com/curriculum/concepts/normalization) — Functional dependencies, 1NF through BCNF, and the cases where denormalising is right.
- [Buffer Pool](https://learn.significanthobbies.com/curriculum/concepts/buffer-pool) — The database's own page cache — why it does not simply trust the OS.

## System Design

Architecture-level thinking: low-level design, scalability, distributed systems, event-driven design, and end-to-end case studies.

- Public page: https://learn.significanthobbies.com/curriculum/tracks/system-design
- Concepts: 26
- Roadmaps: 6

- [Object Modeling](https://learn.significanthobbies.com/curriculum/concepts/object-modeling) — Identifying classes, attributes, relationships.
- [State Machines](https://learn.significanthobbies.com/curriculum/concepts/state-management) — States, transitions, guards.
- [Strategy Pattern](https://learn.significanthobbies.com/curriculum/concepts/strategy-pattern) — Interchangeable algorithms.
- [Observer Pattern](https://learn.significanthobbies.com/curriculum/concepts/observer-pattern) — Pub/sub, event propagation.
- [Factory & Creational](https://learn.significanthobbies.com/curriculum/concepts/factory-creational) — Abstract factory, builder, singleton.
- [Decorator & Structural](https://learn.significanthobbies.com/curriculum/concepts/decorator-structural) — Decorator, adapter, composite.
- [Concurrency Design](https://learn.significanthobbies.com/curriculum/concepts/concurrency-design) — Thread-safety, locks, producer-consumer.
- [Command & Chain](https://learn.significanthobbies.com/curriculum/concepts/command-chain) — Command, undo, chain of responsibility.
- [Booking & Inventory](https://learn.significanthobbies.com/curriculum/concepts/booking-inventory) — Reservation, hold-confirm, optimistic locking.
- [Game/Simulation Design](https://learn.significanthobbies.com/curriculum/concepts/game-design) — Turn engines, board state, rules.
- [Load Balancing](https://learn.significanthobbies.com/curriculum/concepts/load-balancing) — L4/L7, consistent hashing, health checks.
- [Consistent Hashing](https://learn.significanthobbies.com/curriculum/concepts/consistent-hashing) — Ring, virtual nodes, rebalancing.
- [Consensus](https://learn.significanthobbies.com/curriculum/concepts/consensus) — Raft, Paxos, leader election.
- [Distributed Infra](https://learn.significanthobbies.com/curriculum/concepts/distributed-infra) — Service discovery, orchestration.
- [Real-time Systems](https://learn.significanthobbies.com/curriculum/concepts/messaging-realtime) — WebSockets, server-sent events, presence, synchronization, ordering, reconnects, optimistic UI, and conflict handling.
- [Feed Systems](https://learn.significanthobbies.com/curriculum/concepts/social-media) — Fan-out write/read, timeline.
- [Streaming Media](https://learn.significanthobbies.com/curriculum/concepts/streaming-media) — CDN, HLS, transcoding pipeline.
- [Geo Systems](https://learn.significanthobbies.com/curriculum/concepts/location-transport) — Geohash, quadtree, dispatch.
- [Collaboration Systems](https://learn.significanthobbies.com/curriculum/concepts/collaboration-productivity) — Causality, OT, CRDT merge laws, and offline conflict resolution.
- [Search Platform Design](https://learn.significanthobbies.com/curriculum/concepts/search-platform-design) — End-to-end design of a search platform: ingestion, indexing, query, ranking.
- [RAG System Design](https://learn.significanthobbies.com/curriculum/concepts/rag-system-design) — Architecting a production RAG system: ingestion, retrieval, generation, evals.
- [Capacity Estimation](https://learn.significanthobbies.com/curriculum/concepts/capacity-estimation) — Back-of-the-envelope QPS, storage, and bandwidth maths that sizes a design before you draw it.
- [Requirements Scoping](https://learn.significanthobbies.com/curriculum/concepts/requirements-scoping) — Separating functional from non-functional requirements and cutting scope to something buildable.
- [Rate Limiter Design](https://learn.significanthobbies.com/curriculum/concepts/rate-limiter-design) — Token bucket versus sliding window, and making a limiter work across many nodes.
- [Unique ID Generation](https://learn.significanthobbies.com/curriculum/concepts/unique-id-generation) — Snowflake, ULID, and UUIDv7 — unique ids without a central allocator.
- [CDN & Edge Delivery](https://learn.significanthobbies.com/curriculum/concepts/cdn-edge-delivery) — Cache hierarchy, origin shield, and invalidation versus TTL at the edge.

## DSA & Implementation

Fast, clean implementation ability: arrays, graphs, trees, dynamic programming, and the core algorithmic patterns.

- Public page: https://learn.significanthobbies.com/curriculum/tracks/dsa
- Concepts: 27
- Roadmaps: 1

- [Arrays & Hashing](https://learn.significanthobbies.com/curriculum/concepts/array-hashing) — Hash maps, sets, frequency counting.
- [Two Pointers](https://learn.significanthobbies.com/curriculum/concepts/two-pointers) — Converging/diverging pointer scans.
- [Sliding Window](https://learn.significanthobbies.com/curriculum/concepts/sliding-window) — Variable/fixed window over sequences.
- [Stack](https://learn.significanthobbies.com/curriculum/concepts/stack) — LIFO, parsing, monotonic stack.
- [Binary Search](https://learn.significanthobbies.com/curriculum/concepts/binary-search) — Halving sorted search space, predicate search.
- [Linked List](https://learn.significanthobbies.com/curriculum/concepts/linked-list) — Pointer manipulation, fast/slow, reversal.
- [Trees](https://learn.significanthobbies.com/curriculum/concepts/trees) — Binary trees, BSTs, DFS/BFS.
- [Trie](https://learn.significanthobbies.com/curriculum/concepts/tries) — Prefix trees.
- [Heap / Priority Queue](https://learn.significanthobbies.com/curriculum/concepts/heap) — Top-k, k-way merge, scheduling.
- [Backtracking](https://learn.significanthobbies.com/curriculum/concepts/backtracking) — DFS with state restoration, pruning.
- [Graphs](https://learn.significanthobbies.com/curriculum/concepts/graphs) — BFS/DFS, topo sort, union-find.
- [Shortest Path](https://learn.significanthobbies.com/curriculum/concepts/shortest-path) — Dijkstra, Bellman-Ford, A*.
- [Union-Find](https://learn.significanthobbies.com/curriculum/concepts/union-find) — Disjoint set, path compression.
- [1D DP](https://learn.significanthobbies.com/curriculum/concepts/dp-1d) — Linear state recurrences.
- [2D DP](https://learn.significanthobbies.com/curriculum/concepts/dp-2d) — Grid DP, edit distance, knapsack.
- [Greedy](https://learn.significanthobbies.com/curriculum/concepts/greedy) — Local-optimal-as-global proofs.
- [Intervals](https://learn.significanthobbies.com/curriculum/concepts/intervals) — Merge, overlap, sweep line.
- [Math & Geometry](https://learn.significanthobbies.com/curriculum/concepts/math-geometry) — Number theory, modular, geometry.
- [Bit Manipulation](https://learn.significanthobbies.com/curriculum/concepts/bit-manipulation) — Bitwise ops, masks, XOR tricks.
- [Complexity Analysis](https://learn.significanthobbies.com/curriculum/concepts/complexity-analysis) — Big-O, amortised cost, and space complexity — how to argue a bound before writing code.
- [Sorting](https://learn.significanthobbies.com/curriculum/concepts/sorting) — Comparison sorts, stability, in-place versus extra space, and when a linear-time sort is available.
- [Prefix Sums](https://learn.significanthobbies.com/curriculum/concepts/prefix-sums) — Precomputed cumulative arrays that turn repeated range queries into O(1) lookups.
- [Monotonic Stack](https://learn.significanthobbies.com/curriculum/concepts/monotonic-stack) — A stack kept sorted so each element is pushed and popped once, answering next-greater questions in O(n).
- [String Matching](https://learn.significanthobbies.com/curriculum/concepts/string-matching) — Finding a pattern in text in linear time — KMP's failure function and Rabin-Karp's rolling hash.
- [Minimum Spanning Tree](https://learn.significanthobbies.com/curriculum/concepts/minimum-spanning-tree) — Kruskal and Prim — connecting every node at least total cost.
- [Recursion & Induction](https://learn.significanthobbies.com/curriculum/concepts/recursion-and-induction) — Writing recursion you can trust, and solving the recurrence it produces.
- [Quickselect](https://learn.significanthobbies.com/curriculum/concepts/quickselect) — Finding the k-th smallest in expected O(n) by recursing into only one partition.

## Behavioral & Communication

The interview round that is not about code: influence, conflict, ownership, prioritisation, and learning from failure.

- Public page: https://learn.significanthobbies.com/curriculum/tracks/behavioral
- Concepts: 10
- Roadmaps: 1

- [Leadership](https://learn.significanthobbies.com/curriculum/concepts/leadership-and-influence) — Driving outcomes through others.
- [Conflict Resolution](https://learn.significanthobbies.com/curriculum/concepts/conflict-resolution) — Disagreement handling.
- [Decision Making](https://learn.significanthobbies.com/curriculum/concepts/problem-solving-and-decision-making) — Tradeoffs under uncertainty.
- [Collaboration](https://learn.significanthobbies.com/curriculum/concepts/teamwork-and-collaboration) — Cross-functional work.
- [Failure & Learning](https://learn.significanthobbies.com/curriculum/concepts/failure-and-learning) — Owning mistakes, post-mortem.
- [Communication](https://learn.significanthobbies.com/curriculum/concepts/communication) — Written/verbal, audience adaptation.
- [Prioritization](https://learn.significanthobbies.com/curriculum/concepts/time-management-and-prioritization) — Eisenhower, OKR alignment.
- [Innovation](https://learn.significanthobbies.com/curriculum/concepts/innovation-and-creativity) — Novel solutions, experimentation.
- [Customer Obsession](https://learn.significanthobbies.com/curriculum/concepts/customer-obsession) — User-centered tradeoffs.
- [Ownership](https://learn.significanthobbies.com/curriculum/concepts/ownership-and-accountability) — End-to-end responsibility.

## Go-to-Market

Getting a built thing in front of people: positioning, landing pages, SEO, and product analytics.

- Public page: https://learn.significanthobbies.com/curriculum/tracks/go-to-market
- Concepts: 4
- Roadmaps: 1

- [Positioning](https://learn.significanthobbies.com/curriculum/concepts/positioning) — Naming the problem, the audience, and the alternative you beat.
- [Landing Pages](https://learn.significanthobbies.com/curriculum/concepts/landing-pages) — Turning a visitor into an activated user: hero, proof, single CTA.
- [SEO](https://learn.significanthobbies.com/curriculum/concepts/seo) — Programmatic and content SEO: intent, structure, indexability.
- [Product Analytics](https://learn.significanthobbies.com/curriculum/concepts/product-analytics) — Activation, retention, funnels — measuring whether the product works.

## Systems Foundations

Operating systems, networks, concurrency, hardware, runtimes, performance, security, and isolation.

- Public page: https://learn.significanthobbies.com/curriculum/tracks/systems-foundations
- Concepts: 8
- Roadmaps: 2

- [Concurrency Design](https://learn.significanthobbies.com/curriculum/concepts/concurrency-design) — Thread-safety, locks, producer-consumer.
- [Operating System Mechanics](https://learn.significanthobbies.com/curriculum/concepts/operating-system-mechanics) — Processes, threads, virtual memory, scheduling, filesystems, syscalls, and kernel boundaries.
- [Network Protocol Engineering](https://learn.significanthobbies.com/curriculum/concepts/network-protocol-engineering) — Packet flow across Ethernet, IP, TCP/QUIC, TLS, DNS, HTTP, load balancers, and application protocols.
- [Compute, Memory & Storage Hierarchy](https://learn.significanthobbies.com/curriculum/concepts/compute-memory-storage-hierarchy) — CPU caches, NUMA, DRAM, GPU memory, NVMe, object storage, and the movement costs between them.
- [Runtime & Performance Engineering](https://learn.significanthobbies.com/curriculum/concepts/runtime-performance-engineering) — Profiling, allocation, JIT/AOT execution, garbage collection, scheduling, contention, and tail latency.
- [Security & Isolation Boundaries](https://learn.significanthobbies.com/curriculum/concepts/security-isolation-boundaries) — Threat models, least privilege, capabilities, process and VM isolation, side channels, and secure defaults.
- [Data Representation](https://learn.significanthobbies.com/curriculum/concepts/data-representation) — Binary and hexadecimal, two's complement, IEEE-754 floating point, Unicode, byte order, and serialized bytes.
- [Program Memory Model](https://learn.significanthobbies.com/curriculum/concepts/program-memory-model) — Pointers, stack frames, heap allocation, object lifetime, executable loading, and the transition from a program on disk to a running process.

## Infrastructure & Platforms

Cloud infrastructure, containers, CI/CD, orchestration, reliability, observability, sandboxes, and infrastructure automation.

- Public page: https://learn.significanthobbies.com/curriculum/tracks/infrastructure-platforms
- Concepts: 10
- Roadmaps: 1

- [Retries & DLQ](https://learn.significanthobbies.com/curriculum/concepts/retries-dlq) — Backoff + jitter, poison messages, dead-letter queues.
- [Background Jobs](https://learn.significanthobbies.com/curriculum/concepts/background-jobs) — Offloading slow work to workers: scheduling, concurrency, visibility.
- [Observability](https://learn.significanthobbies.com/curriculum/concepts/monitoring-analytics) — Metrics, logs, traces, context propagation, semantic conventions, sampling, collectors, and telemetry pipelines.
- [Cloud Infrastructure](https://learn.significanthobbies.com/curriculum/concepts/cloud-infrastructure) — Regions, zones, networks, compute, managed storage, identity, load balancing, and control planes.
- [Containers & Kubernetes](https://learn.significanthobbies.com/curriculum/concepts/containers-kubernetes) — Namespaces, cgroups, OCI images, container runtimes, Kubernetes scheduling, controllers, networking, and storage.
- [CI/CD & Developer Environments](https://learn.significanthobbies.com/curriculum/concepts/cicd-developer-environments) — Hermetic builds, reproducible environments, test gates, artifacts, previews, progressive delivery, and rollback.
- [Scheduling & Orchestration](https://learn.significanthobbies.com/curriculum/concepts/platform-scheduling-orchestration) — Placement, queues, priorities, quotas, fairness, preemption, autoscaling, and reconciliation loops.
- [Reliability & Fault Tolerance](https://learn.significanthobbies.com/curriculum/concepts/reliability-fault-tolerance) — SLOs, error budgets, redundancy, graceful degradation, overload control, and failure-domain design.
- [Sandboxes & Execution Environments](https://learn.significanthobbies.com/curriculum/concepts/sandbox-execution-environments) — Processes, containers, microVMs, V8 isolates, WebAssembly, capabilities, quotas, and untrusted-code execution.
- [Infrastructure Automation](https://learn.significanthobbies.com/curriculum/concepts/infrastructure-automation) — Declarative infrastructure, state, plans, drift detection, policy checks, secrets boundaries, and safe changes.

## Distributed Systems

Coordination, replication, partitioning, event systems, caching, durable workflows, consistency, and recovery.

- Public page: https://learn.significanthobbies.com/curriculum/tracks/distributed-systems
- Concepts: 11
- Roadmaps: 1

- [Caching](https://learn.significanthobbies.com/curriculum/concepts/caching) — Cache-aside, write-through, eviction policies.
- [Message Queues](https://learn.significanthobbies.com/curriculum/concepts/message-queues) — Kafka, SQS, exactly-once vs at-least-once.
- [Sharding](https://learn.significanthobbies.com/curriculum/concepts/sharding) — Range/hash/geo partitioning.
- [Replication](https://learn.significanthobbies.com/curriculum/concepts/replication) — Leader-follower, multi-leader, quorum.
- [CAP & Consistency Models](https://learn.significanthobbies.com/curriculum/concepts/cap-theorem) — Strong/eventual/causal, PACELC.
- [Consensus](https://learn.significanthobbies.com/curriculum/concepts/consensus) — Raft, Paxos, leader election.
- [Distributed Infra](https://learn.significanthobbies.com/curriculum/concepts/distributed-infra) — Service discovery, orchestration.
- [Real-time Systems](https://learn.significanthobbies.com/curriculum/concepts/messaging-realtime) — WebSockets, server-sent events, presence, synchronization, ordering, reconnects, optimistic UI, and conflict handling.
- [Event Streaming & Kafka](https://learn.significanthobbies.com/curriculum/concepts/event-streaming-kafka) — Partitioned logs, producers, consumer groups, offsets, ordering, delivery semantics, backpressure, and stream processing.
- [Distributed Workflows & Temporal](https://learn.significanthobbies.com/curriculum/concepts/distributed-workflows-temporal) — Durable execution, event histories, deterministic replay, activities, retries, timers, and long-running workflows.
- [Distributed Failure Recovery](https://learn.significanthobbies.com/curriculum/concepts/distributed-failure-recovery) — Partial failure, timeouts, retries, deduplication, fencing, repair, anti-entropy, and disaster recovery.

## Inference & Serving

Inference engines, batching, KV caches, attention kernels, decoding, routing, hardware utilization, and serving economics.

- Public page: https://learn.significanthobbies.com/curriculum/tracks/inference-serving
- Concepts: 12
- Roadmaps: 3

- [Model Routing](https://learn.significanthobbies.com/curriculum/concepts/model-routing) — Sending each request to the cheapest model that can handle it.
- [Browser ML Runtime](https://learn.significanthobbies.com/curriculum/concepts/ml-browser-runtime) — Web Workers, WASM, OPFS, TypedArrays.
- [WebGPU Compute](https://learn.significanthobbies.com/curriculum/concepts/ml-webgpu) — WGSL, compute kernels, matmul, CPU parity.
- [vLLM & Inference Engines](https://learn.significanthobbies.com/curriculum/concepts/inference-engines) — Request scheduling, model execution, memory management, distributed serving, APIs, and engine architecture.
- [Continuous Batching](https://learn.significanthobbies.com/curriculum/concepts/continuous-batching) — Iteration-level scheduling, dynamic admission, prefill/decode interleaving, chunked prefill, and fairness.
- [KV Caching & PagedAttention](https://learn.significanthobbies.com/curriculum/concepts/kv-cache-paged-attention) — Attention-state reuse, KV memory sizing, paging, fragmentation, prefix caching, eviction, and multi-tenant pressure.
- [FlashAttention & Attention Kernels](https://learn.significanthobbies.com/curriculum/concepts/flashattention-kernels) — IO-aware tiling, fused kernels, SRAM/HBM movement, numerical stability, and hardware-aware attention.
- [Speculative Decoding](https://learn.significanthobbies.com/curriculum/concepts/speculative-decoding) — Draft models, token verification, acceptance rates, tree speculation, latency, and quality preservation.
- [GPU Utilization](https://learn.significanthobbies.com/curriculum/concepts/gpu-utilization) — Compute occupancy, memory bandwidth, kernel launch overhead, tensor parallelism, profiling, and saturation.
- [Inference Cost & Latency Optimization](https://learn.significanthobbies.com/curriculum/concepts/inference-cost-latency) — Time to first token, inter-token latency, throughput, tail latency, utilization, quality, and cost per request.
- [Local & On-device Inference](https://learn.significanthobbies.com/curriculum/concepts/local-on-device-inference) — llama.cpp, WebGPU, mobile accelerators, model formats, privacy, offline operation, and constrained memory.
- [Inference Hardware](https://learn.significanthobbies.com/curriculum/concepts/inference-hardware) — GPUs, TPUs, NPUs, CPUs, memory bandwidth, interconnects, topology, precision support, and deployment fit.

## Agent Systems

Agent loops, tools, memory, MCP, coordination, durable execution, permissions, computer use, and long-running work.

- Public page: https://learn.significanthobbies.com/curriculum/tracks/agent-systems
- Concepts: 17
- Roadmaps: 2

- [Tool Calling](https://learn.significanthobbies.com/curriculum/concepts/tool-calling) — Letting an LLM invoke functions/APIs via structured calls.
- [Agent Loops](https://learn.significanthobbies.com/curriculum/concepts/agent-loops) — The plan → act → observe loop, with memory and stopping conditions.
- [Agent Memory & Context Management](https://learn.significanthobbies.com/curriculum/concepts/agent-memory-context) — Working context, summaries, retrieval, episodic state, durable memory, compaction, provenance, and forgetting.
- [MCP & Integrations](https://learn.significanthobbies.com/curriculum/concepts/mcp-integrations) — Model Context Protocol hosts, clients, servers, tools, resources, prompts, transports, capability negotiation, and trust.
- [Multi-agent Coordination](https://learn.significanthobbies.com/curriculum/concepts/multi-agent-coordination) — Delegation, specialization, shared state, handoffs, arbitration, budgets, and avoiding coordination overhead.
- [Durable Agent Execution](https://learn.significanthobbies.com/curriculum/concepts/durable-agent-execution) — Checkpointed loops, resumable tools, idempotency, leases, event histories, retries, and crash recovery.
- [Agent Permissions & Sandboxing](https://learn.significanthobbies.com/curriculum/concepts/agent-permissions-sandboxing) — Capability grants, read/write scopes, approval gates, secret isolation, network policy, quotas, and audit logs.
- [Browser & Computer-use Agents](https://learn.significanthobbies.com/curriculum/concepts/browser-computer-use-agents) — DOM and accessibility-tree control, screenshots, visual grounding, action planning, waits, recovery, and confirmation.
- [Agent Communication & Interfaces](https://learn.significanthobbies.com/curriculum/concepts/agent-communication-interfaces) — Typed messages, events, artifacts, streaming updates, human checkpoints, agent-to-agent protocols, and UI status.
- [Long-running & Scheduled Agents](https://learn.significanthobbies.com/curriculum/concepts/long-running-scheduled-agents) — Cron triggers, queues, leases, heartbeats, deadlines, cancellation, checkpoints, notifications, and cost budgets.
- [Repository Instruction Topology](https://learn.significanthobbies.com/curriculum/concepts/repository-instruction-topology) — Repository-wide and path-local instructions, precedence, ownership boundaries, and concise executable guidance for coding agents.
- [Agent Environment Contracts](https://learn.significanthobbies.com/curriculum/concepts/agent-environment-contracts) — Deterministic bootstrap, dependency and runtime discovery, readiness probes, isolated workspaces, and explicit validation commands.
- [Agent Work State & Handoffs](https://learn.significanthobbies.com/curriculum/concepts/agent-work-state-handoffs) — Versioned goals, plans, checkpoints, evidence, blockers, and next actions that let a new session resume without relying on hidden conversational memory.
- [Agent Scope Control](https://learn.significanthobbies.com/curriculum/concepts/agent-scope-control) — Bounded task decomposition, allowed edit roots, budgets, change-size limits, and escalation when evidence invalidates the plan.
- [Independent Agent Verification](https://learn.significanthobbies.com/curriculum/concepts/independent-agent-verification) — Maker-checker role separation, independent evidence gathering, adversarial review, and acceptance gates that do not trust the producer's self-report.
- [Agent Run Lifecycle](https://learn.significanthobbies.com/curriculum/concepts/agent-run-lifecycle) — Run initialization, leases and heartbeats, progress transitions, budgets, completion evidence, cancellation, escalation, and safe termination.
- [Harness Evaluation](https://learn.significanthobbies.com/curriculum/concepts/harness-evaluation) — Task suites, outcome rubrics, trajectory metrics, cost and latency budgets, ablations, and regression gates for the harness rather than the model alone.

## Evaluation & AI Reliability

LLM and agent evaluations, regression gates, failure detection, tracing, verification, human review, and quality economics.

- Public page: https://learn.significanthobbies.com/curriculum/tracks/ai-reliability
- Concepts: 14
- Roadmaps: 2

- [Prompt & Version Logging](https://learn.significanthobbies.com/curriculum/concepts/prompt-versioning) — Treating prompts as versioned artifacts with logged inputs/outputs.
- [LLM Evals](https://learn.significanthobbies.com/curriculum/concepts/llm-evals) — Measuring LLM output quality with datasets, graders, and LLM-as-judge.
- [Model Evaluation](https://learn.significanthobbies.com/curriculum/concepts/ml-evaluation) — Held-out loss, baselines, hallucination, leakage.
- [Coding-agent Benchmarks](https://learn.significanthobbies.com/curriculum/concepts/coding-agent-benchmarks) — Issue resolution tasks, repository setup, patch grading, test-based scoring, contamination, and benchmark validity.
- [Tool-use Evaluations](https://learn.significanthobbies.com/curriculum/concepts/tool-use-evaluations) — Tool selection, argument correctness, sequencing, recovery, side-effect safety, and end-state verification.
- [AI Regression Testing](https://learn.significanthobbies.com/curriculum/concepts/ai-regression-testing) — Frozen eval sets, golden cases, rubric versions, stochastic thresholds, canaries, and release gates.
- [Hallucination & Failure Detection](https://learn.significanthobbies.com/curriculum/concepts/hallucination-failure-detection) — Unsupported claims, citations, abstention, tool errors, constraint violations, uncertainty, and escalation.
- [Agent Observability](https://learn.significanthobbies.com/curriculum/concepts/agent-observability) — Runs, steps, prompts, model calls, tool calls, tokens, costs, errors, state changes, and outcome metrics.
- [Tracing & Replay](https://learn.significanthobbies.com/curriculum/concepts/tracing-replay) — Deterministic inputs, event logs, snapshots, prompt/model versions, tool fixtures, and counterfactual re-execution.
- [Evidence-backed Verification](https://learn.significanthobbies.com/curriculum/concepts/evidence-backed-verification) — Claims, source provenance, executable checks, screenshots, diffs, test outputs, and acceptance criteria.
- [Human Review Systems](https://learn.significanthobbies.com/curriculum/concepts/human-review-systems) — Review queues, risk routing, disagreement, calibration, escalation, auditability, and learning from corrections.
- [Quality, Cost & Latency Measurement](https://learn.significanthobbies.com/curriculum/concepts/quality-cost-latency-measurement) — Task success, calibrated quality, token and tool cost, latency distributions, reliability, and Pareto frontiers.
- [Independent Agent Verification](https://learn.significanthobbies.com/curriculum/concepts/independent-agent-verification) — Maker-checker role separation, independent evidence gathering, adversarial review, and acceptance gates that do not trust the producer's self-report.
- [Harness Evaluation](https://learn.significanthobbies.com/curriculum/concepts/harness-evaluation) — Task suites, outcome rubrics, trajectory metrics, cost and latency budgets, ablations, and regression gates for the harness rather than the model alone.

## Developer Tools & Code Intelligence

Code review, analysis, testing infrastructure, repository graphs, coding agents, supply-chain health, and remediation.

- Public page: https://learn.significanthobbies.com/curriculum/tracks/developer-tools
- Concepts: 13
- Roadmaps: 2

- [Code Review Systems](https://learn.significanthobbies.com/curriculum/concepts/code-review-systems) — Diff understanding, intent, correctness, maintainability, risk ranking, review workflows, and actionable findings.
- [Static & Dynamic Analysis](https://learn.significanthobbies.com/curriculum/concepts/static-dynamic-analysis) — ASTs, control/data flow, abstract interpretation, symbolic execution, sanitizers, profiling, and runtime instrumentation.
- [Testing Infrastructure](https://learn.significanthobbies.com/curriculum/concepts/testing-infrastructure) — Unit, integration, contract, E2E, property, fuzz, hermetic environments, fixtures, sharding, and flaky-test control.
- [Codebase Graphs](https://learn.significanthobbies.com/curriculum/concepts/codebase-graphs) — Symbols, references, calls, imports, ownership, data flow, build targets, and graph queries over repositories.
- [Dependency & Blast-radius Analysis](https://learn.significanthobbies.com/curriculum/concepts/dependency-blast-radius) — Direct and transitive dependencies, affected targets, ownership, runtime consumers, schema impact, and change risk.
- [IDE & CLI Tooling](https://learn.significanthobbies.com/curriculum/concepts/ide-cli-tooling) — Language servers, editor protocols, terminal UX, diagnostics, completions, commands, configuration, and automation.
- [Coding Agent Systems](https://learn.significanthobbies.com/curriculum/concepts/coding-agent-systems) — Repository context, planning, file edits, tools, tests, sandboxes, review loops, and patch delivery.
- [Repository Intelligence](https://learn.significanthobbies.com/curriculum/concepts/repository-intelligence) — Structure, symbols, history, ownership, conventions, architecture, semantic search, and change-aware retrieval.
- [Software Supply-chain Health](https://learn.significanthobbies.com/curriculum/concepts/software-supply-chain-health) — Dependency provenance, lockfiles, SBOMs, signing, build integrity, vulnerabilities, update policy, and release attestations.
- [Automated Debugging & Remediation](https://learn.significanthobbies.com/curriculum/concepts/automated-debugging-remediation) — Failure reproduction, hypothesis generation, telemetry, fault localization, minimal patches, validation, rollback, and learning.
- [Repository Instruction Topology](https://learn.significanthobbies.com/curriculum/concepts/repository-instruction-topology) — Repository-wide and path-local instructions, precedence, ownership boundaries, and concise executable guidance for coding agents.
- [Agent Environment Contracts](https://learn.significanthobbies.com/curriculum/concepts/agent-environment-contracts) — Deterministic bootstrap, dependency and runtime discovery, readiness probes, isolated workspaces, and explicit validation commands.
- [Agent Scope Control](https://learn.significanthobbies.com/curriculum/concepts/agent-scope-control) — Bounded task decomposition, allowed edit roots, budgets, change-size limits, and escalation when evidence invalidates the plan.

## Application Engineering

Backend, web, mobile, product analytics, UX, real-time applications, interactive systems, and distribution loops.

- Public page: https://learn.significanthobbies.com/curriculum/tracks/application-engineering
- Concepts: 4
- Roadmaps: 1

- [Game/Simulation Design](https://learn.significanthobbies.com/curriculum/concepts/game-design) — Turn engines, board state, rules.
- [Web & Mobile Engineering](https://learn.significanthobbies.com/curriculum/concepts/web-mobile-engineering) — Web and native lifecycles, rendering, navigation, state, networking, offline behavior, accessibility, and release constraints.
- [UX & Interface Design](https://learn.significanthobbies.com/curriculum/concepts/ux-interface-design) — User goals, information architecture, interaction states, feedback, accessibility, usability testing, and design systems.
- [2D/3D Interactive Systems](https://learn.significanthobbies.com/curriculum/concepts/interactive-2d-3d-systems) — Scene graphs, render loops, input, animation, physics, GPU pipelines, asset loading, and performance budgets.

## Multimodal & Spatial Computing

Vision, pose, voice, generation, on-device intelligence, robotics, spatial interfaces, and human-computer interaction.

- Public page: https://learn.significanthobbies.com/curriculum/tracks/multimodal-spatial
- Concepts: 8
- Roadmaps: 1

- [Multimodal Models](https://learn.significanthobbies.com/curriculum/concepts/multimodal-models) — Joint text, image, audio, and video representations, encoders, projectors, fusion, generation, and cross-modal evaluation.
- [Vision Models](https://learn.significanthobbies.com/curriculum/concepts/vision-models) — Classification, detection, segmentation, embeddings, vision transformers, data augmentation, and visual evaluation.
- [Pose & Motion Tracking](https://learn.significanthobbies.com/curriculum/concepts/pose-motion-tracking) — Landmarks, skeletons, optical flow, temporal smoothing, identity tracking, calibration, occlusion, and latency.
- [Voice & Audio Systems](https://learn.significanthobbies.com/curriculum/concepts/voice-audio-systems) — Capture, codecs, streaming, speech recognition, synthesis, turn detection, noise handling, latency, and conversational UX.
- [Image & Video Generation](https://learn.significanthobbies.com/curriculum/concepts/image-video-generation) — Diffusion and transformer generation, conditioning, latent spaces, control, consistency, safety, and media evaluation.
- [Robotics Systems](https://learn.significanthobbies.com/curriculum/concepts/robotics-systems) — Sensing, localization, mapping, planning, control, simulation, safety, real-time loops, and hardware interfaces.
- [Spatial Interfaces](https://learn.significanthobbies.com/curriculum/concepts/spatial-interfaces) — Coordinate systems, anchors, tracking, depth, occlusion, hand/eye input, world understanding, and spatial UI.
- [Human-Computer Interaction](https://learn.significanthobbies.com/curriculum/concepts/human-computer-interaction) — Human perception, cognition, motor control, interaction techniques, accessibility, evaluation, and responsible design.