Describe what you want to build and get a clear architecture back, components, data flow, risks, and an MVP cut, not code. Uses your own API key, kept in your browser and sent only to your provider.
🔒 Your key is stored only in this browser (localStorage) and sent directly to your provider, never to KB Cafe. You pay your provider for the call.
Before you write a line, the useful question is what are the pieces and how do they connect? This tool takes a plain description and returns an architecture, the frontend, backend, storage, any retrieval layer, auth, the data flow, the risks, and a minimal first version, so you can see the shape of the system. It deliberately doesn’t write code; the value is the map, not the bricks.
This is the one tool here that calls a real model, so it needs a key. KB Cafe stays true to its rule by keeping it yours: the key lives in your browser and the request goes straight to OpenAI or Anthropic, never through our servers. We never see your key, your prompt, or the output, and you only pay your provider’s normal rate.
Because the call is browser-to-provider, the prompt that powers this is visible in the page, that’s the honest trade for a no-backend, no-cost-to-you design. Get a key from your provider’s dashboard; a small, cheap model is plenty for an architecture sketch.
No. The key is in your browser’s localStorage and the request goes directly to your provider’s API. Nothing routes through KB Cafe, there’s no backend here at all.
The hard part of building isn’t typing, it’s deciding the components and how data flows. A good architecture sketch makes the code obvious and catches problems early.
Whatever your provider charges for the tokens, usually a fraction of a cent on a small model. Estimate it with the Cost Calculator.
Design the agent flow in the Pattern Builder, map the concepts with the Stack Explainer, or browse AI Explained.