Step into real engineering systems. Assemble, modify, and break them locally — guided, but you build it.
Playgrounds →
This platform drops you into production-like codebases and architectures. You work locally, make decisions, and see the consequences — no cloud sandboxes, no magic abstractions.
Start building →This is not a tutorial platform. It's a place to practice engineering decisions inside real systems.
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Build real systems locally. Follow guidance at first. Take ownership over time.
You start with full guidance and reference solutions. As you progress, hints fade and responsibility shifts to you.
No cloud dependencies. No expired access. The code stays on your machine.
No simulations. No cloud sandboxes. Build and run everything on your laptop.
You assemble components, explore trade-offs, and debug failure modes — with guidance, reference solutions, and responsibility.
You start with guided assembly and full reference solutions to understand the system deeply.
Later, guidance steps back — and responsibility moves to you.
Use VS Code, Vim, or any editor you prefer.
Working in your real development environment builds the same workflows and habits you'll use in practice.
The reference project syncs to your local folder automatically.
Compare your code with the reference implementation, inspect differences, and learn by reconstructing it yourself.
See exactly what changes at each step.
Every modification is shown as a clear diff, with explanations for why it matters.
Navigate systems, inspect code, and track your progress
without leaving your local workflow.
Every playground leads to a finished application you can run, inspect, and extend locally.
Not fragments, not demos — complete systems with structure, state, and behavior.
Ready-to-use prompts for AI coding assistants.
Recreate each step using Claude, Cursor, or your preferred tool — if you want shortcuts.
Your AI agent can communicate with you in your native language.
Any language is supported.
It works with your own AI agent, asks questions, highlights weak assumptions, and challenges your decisions without replacing your reasoning.
Connect your AI agent from the browser and turn it into a coding mentor for every step.
While you learn, full project sources are built locally in parallel on your machine.
Enter playground →
Both modes are supported
Build with your own hands when you want full mechanical understanding, or delegate implementation to AI while you stay focused on architecture and outcomes.
Own every technical decision and build deep execution confidence by writing and validating each layer yourself.
Move faster by orchestrating prompts, tools, and constraints while AI handles implementation under your technical control.
Engineering notes, new playgrounds, and platform evolution.
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