Understand systems.
Don't just use them.

AI mentor for experienced engineers. Build Redis, Git, and SQLite from scratch while an AI reviews every line, adapts to your level, and teaches you what tutorials never will.

Start the Redis Challenge →
anneal session
$ anneal start --challenge redis
Starting: Build your own Redis
Stage 3/12: Implement RESP protocol parser

> Parsing bulk strings...
Anneal: Your parser handles \r\n correctly, but consider edge cases where the bulk string length is -1 (null bulk string). Redis clients send these frequently. Want me to generate a test case?

$ anneal hint --context
Anneal: Look at how the official Redis source handles this in networking.c line 1087. The pattern is simpler than you'd expect.

Stage 3 complete. Difficulty adapting...
Next: Stage 4 - Implement SET with expiry
the gap

Every AI tool helps you write code faster.
None help you understand it deeper.

Copilot autocompletes your functions. Cursor refactors your files. But when you need to debug a distributed system at 2am, speed doesn't matter. Understanding does. Anneal builds that understanding by making you construct real systems from nothing.

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AI mentor, not AI autocomplete

Reviews your architecture decisions in real-time. Points you to relevant source code in real projects. Explains the "why" behind systems design, not just the "how."

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Infinite challenges

Not limited to a fixed library. AI generates new "build from scratch" challenges calibrated to your skill level. Redis today, a load balancer tomorrow, a compiler next week.

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Adaptive difficulty

Struggling with memory management? More hints, smaller steps. Crushing network protocols? Fewer guardrails, harder edge cases. The AI matches your pace.

Built for engineers who build.

If you've ever wanted to understand how the tools you depend on actually work under the hood, Anneal is where you do it.

Build your own Redis any language
Build your own Git any language
Build your own SQLite any language
Build your own Docker any language
Build your own BitTorrent any language
Build your own HTTP server any language
Build your own DNS resolver any language
Build your own load balancer any language

Forged through building.

The best engineers don't just use systems. They understand how to build them. Anneal is where that understanding is forged, one challenge at a time, with an AI that never gets tired of teaching.

Start Building →