Changelog

What's new.

Recent ships. Newest first. 25 entries since the launch.

Apr 30, 2026
contentfeature
Path 7 (AI Agents) + News + Resources + Tools + Compare + SEO
Major content + SEO expansion: 7th learning path AI Agents (10 lessons on ReAct, tool use, planning, MCP, memory, multi-agent, safety, evaluation). New sections: /news (curated AI industry news with NewsArticle JSON-LD), /resources (~30 curated papers/books/blogs/talks), /tools (40+ AI tools categorized — APIs, vector DBs, agent frameworks, eval, serving), /compare/models (frontier models side-by-side: pricing, context, capabilities, when-to-use). SEO: llms.txt at the root for AI/LLM crawlers, LearningResource JSON-LD on every lesson, breadcrumb schemas across new pages, sitemap covering all of it. Footer reorganized into 5 columns (Learn / Careers / Discover / Company / Legal). Cmd+K palette indexes 250+ targets now.
Apr 30, 2026
featurefix
Lesson outline sidebar + 3 production bugs fixed via tests
On xl+ screens the lesson runner now shows a jumpable beat outline in the right margin (icon per kind, completion check, IntersectionObserver-driven active highlight). Vitest suite grew to 58 tests with a data-integrity check (every path → real lessons, every career → real paths, every glossary cross-link resolves). Caught and fixed three production bugs: getProgress() was returning the mutable DEFAULT_PROGRESS constant (state leakage); gradeCard could grow interval past Date's representable range on long easy streaks (capped at 365d); pushRecent couldn't recover from a corrupt JSON blob.
Apr 30, 2026
content
/skills index + 2 more blog articles
New /skills page maps every skill across the catalog to which careers want it (with weight bars in each role's accent gradient) and which paths cover it. Two new launch articles: "Eval discipline" and "When NOT to build a RAG". Five blog posts total now.
Apr 30, 2026
contentfeature
Blog with 3 launch articles + RSS feed
/blog index, prerendered detail pages with BlogPosting JSON-LD, three substantive articles ('From prompt to production', 'Why "Duolingo for AI" doesn't work', 'Six AI careers in 2026'), and an RSS 2.0 feed at /blog/feed.xml auto-discovered via the layout's <link rel="alternate">. Hero gets a 4-up stats strip (62 lessons · 6 paths · 10 careers · 50 glossary terms).
Apr 30, 2026
securityperf
Security headers, route-level loading, recent + OG polish
Strict CSP, HSTS, X-Frame-Options, Permissions-Policy, X-Content-Type-Options, Referrer-Policy on every response. Route-level loading.tsx for /app/* so the dashboard skeleton paints before any chunk loads. Per-career dynamic OG images. "Recently viewed" lessons widget on the dashboard.
Apr 30, 2026
feature
Real Python in 5 more lessons
Pyodide-powered python-run beats added to aef-02 (vectors), aef-03 (matrices → real linear-layer forward pass), aef-04 (softmax with temperature), aef-05 (gradient descent on a 2D paraboloid), and rag-02 (batched cosine similarity). Each one sits next to the JS demo so you see the same idea in both languages.
Apr 30, 2026
feature
SVG streak ring on the dashboard
Replaces the plain streak tile. The ring closes around your day's progress, recolors based on state (emerald = done today, amber = open, gray = no streak), and shows current count + a Flame in the center.
Apr 30, 2026
featurefix
Keyboard polish — Enter advances, focus restores after modals
Pressing Enter in the lesson runner now advances when no input is focused (skips when typing in textareas, prompt challenges, or Mira). All three modals (Mira, Notes, Cmd+K) now restore focus to whatever was focused before the modal opened — a real WCAG 2.4.3 compliance fix.
Apr 29, 2026
featureperf
Production hardening — error boundary, toast system, structured error logging
Branded app/error.tsx for any uncaught render error (logs to PostHog and console). Tiny pub/sub toast store with success / error / info / warning helpers. Lesson completion now fires a celebration toast in addition to the XP animation. Replaced inline alert() calls.
Apr 29, 2026
featureperf
Service worker + offline reading
Real offline support — lessons you've opened on a device read without a connection. Cache-first on build assets, network-first with cache fallback for HTML, untouched on /api and /auth. /offline page + an offline indicator pill at the bottom when navigator.onLine flips.
Apr 29, 2026
feature
Cmd+K command palette
137 jump-to-anywhere targets across pages, paths, careers, lessons, and glossary terms. Lazy-loaded index keeps marketing-page bundles at 111 kB. Keyboard nav (↑↓ Enter Esc); mouse hover updates active row.
Apr 29, 2026
feature
Per-lesson notes + notes index
Floating "Notes" button in every lesson runner — auto-saves to localStorage, debounced. New /app/notes page lists every lesson you've annotated.
Apr 28, 2026
content
10 careers with a filterable explorer
Catalog grew from 6 → 10. Added AI Product Manager, Data Engineer (AI-focused), Computer Vision Engineer, AI Solutions Architect. /careers is now searchable by role or skill, filterable by demand, sortable by salary or A-Z.
Apr 28, 2026
fix
Mobile responsive pass
Skill tree falls back to a vertical list on phones (React Flow doesn't fit). Hero, sections, lesson runner, Mira button all tightened. Bottom-bar padding fixed so the last beat isn't cropped on iOS.
Apr 28, 2026
feature
Free during launch
Subscription pricing UI removed everywhere. Mira tutor: unlimited and free. Stripe code kept in the repo for re-enable.
Apr 28, 2026
content
AI Engineering Foundations path — 10 lessons
Final path authored. Python for ML, vectors, matrices, probability, gradient descent, train/val/test, loss functions, regularization, hand-written neural net, training-debug capstone. All six paths are now fully written. 62 lessons total.
Apr 28, 2026
content
Deployment & MLOps path — 10 lessons
Inference servers (vLLM/TGI/Triton), GPU choice, containers, autoscaling cold-start asymmetry, cost optimization, monitoring, shadow/canary/A-B, CI/CD, capstone.
Apr 28, 2026
content
Fine-tuning path — 10 lessons
When NOT to fine-tune (decision tree), LoRA/QLoRA, dataset design, real Python script, hyperparameters that matter, evaluation, RLHF/DPO, catastrophic forgetting, hosting, capstone.
Apr 28, 2026
feature
Cross-device progress sync
Local-first: localStorage stays the source of truth. When authenticated, debounced upserts to Supabase (profiles, user_stats, lesson_progress, review_cards). Pulls remote → local on sign-in.
Apr 28, 2026
feature
Spaced-repetition review queue
SM-2-lite scheduler. Auto-enqueues check beats from completed lessons. /app/review session of up to 10 due cards. Easy / Hard / Wrong grading.
Apr 28, 2026
feature
Certificates of completion
Pure-SVG certificate generator. Editable display name, downloadable, LinkedIn share. Locked until path is fully complete.
Apr 28, 2026
feature
Mira AI tutor
Claude Sonnet 4.6 with prompt caching on the lesson context (~80% cost cut on cached prefix). Streaming SSE. Floating chat panel inside every lesson.
Apr 28, 2026
content
RAG & Vector Databases path — 10 lessons
Cosine similarity, chunking strategies, vector DBs, end-to-end mini-RAG, hybrid search + rerankers, failure modes, eval (P@k / R@k), production cost/latency/freshness, support-ticket capstone.
Apr 28, 2026
content
LLMs & Transformers path — 10 lessons
Tokens, embeddings, attention (with custom SVG diagrams), transformer block internals, positional encoding, sampling, model cards, KV cache, reasoning models, model-picking capstone.
Apr 28, 2026
launch
Initial launch — six learning paths, 12 lessons in Prompt Engineering
Premium landing page with interactive prompt demo, six paths in catalog, full Prompt Engineering content (12 lessons), career explorer, CertQuests handoff, dashboard with XP/streak/continue.

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What's new.

Path 7 (AI Agents) + News + Resources + Tools + Compare + SEO

Lesson outline sidebar + 3 production bugs fixed via tests

/skills index + 2 more blog articles

Blog with 3 launch articles + RSS feed

Security headers, route-level loading, recent + OG polish

Real Python in 5 more lessons

SVG streak ring on the dashboard

Keyboard polish — Enter advances, focus restores after modals

Production hardening — error boundary, toast system, structured error logging

Service worker + offline reading

Cmd+K command palette

Per-lesson notes + notes index

10 careers with a filterable explorer

Mobile responsive pass

Free during launch

AI Engineering Foundations path — 10 lessons

Deployment & MLOps path — 10 lessons

Fine-tuning path — 10 lessons

Cross-device progress sync

Spaced-repetition review queue

Certificates of completion

Mira AI tutor

RAG & Vector Databases path — 10 lessons

LLMs & Transformers path — 10 lessons

Initial launch — six learning paths, 12 lessons in Prompt Engineering