The AI developer agent that builds production-ready apps from a plain-language description — planning, coding, debugging and asking for review as it goes. An open alternative to Lovable and Bolt.
Pythagora (born as the famous GPT Pilot research project) approaches AI app building like a real engineering team: it interviews you about requirements, plans the architecture, writes code task by task, debugs its own output and pauses for your review at sensible checkpoints.
That step-by-step, human-in-the-loop process is the difference from one-shot generators — it can build genuinely larger apps because it maintains context and verifies work as it goes, running locally against your own OpenAI or Anthropic keys.
Open-sourced with a VS Code extension and a commercial platform on top, Pythagora is the transparent alternative to closed prompt-to-app builders like Lovable and Bolt.
The core (GPT Pilot) is open source and free to run with your own API keys; Pythagora also offers a paid hosted platform with a more polished experience.
Lovable and Bolt are closed, hosted one-shot builders; Pythagora is open source, runs locally with your keys, and builds step-by-step with reviews — better suited to larger, real apps.
Full-stack web apps — typically Node/React style stacks — including database, API and frontend, with tests along the way.
You can get far without coding, but development knowledge helps a lot when guiding reviews and finishing production details.
Your own OpenAI or Anthropic keys — you control the model and the spend.