Windmill Has a Free API: The Open-Source Retool Alternative That Turns Scripts Into Internal Tools, Workflows, and APIs

Your team needs an internal dashboard to manage users. A Retool license is $10/user/month. You could build it from scratch — but that's 2 weeks of React. Windmill lets you write a Python or TypeScript script and it automatically generates the UI, handles scheduling, logging, permissions, and error handling. What Windmill Actually Does Windmill is an open-source platform for building internal tools, workflows, and APIs from scripts. Write a function in Python, TypeScript, Go, Bash, SQL, or GraphQL — Windmill auto-generates a form UI from the function's parameters, handles execution, scheduling, retries, and audit logging. Think of it as Retool + Temporal + Cron combined into one platform. Scripts become internal tools with auto-generated UIs. Chain scripts into workflows. Expose them as webhooks/APIs. Schedule them as cron jobs. All with version control, RBAC, and approval flows. Self-hosted (free, open-source AGPLv3) or Windmill Cloud (free tier: 1,000 executions/month). The self-hoste