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Windmill

Turn scripts into workflows, UIs, and APIs at scale

freemiumopen sourceupdated Aug 16, 2026

Windmill is an open-source workflow engine and developer platform built in Rust that turns scripts in Python, TypeScript, Go, Bash, SQL, and other languages into auto-generated UIs, API endpoints, workflows, data pipelines, AI agents, and scheduled jobs. The project publishes performance benchmarks against Airflow/Prefect/Temporal, supports Docker/Kubernetes self-hosting, and offers paid enterprise features.

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A detailed review by the aicoolies team — click to read

Windmill is an open-source platform that combines a workflow engine, an internal app builder, and a script execution runtime into a single self-hostable product. The backend is written in Rust with stateless API servers and workers pulling jobs from a PostgreSQL queue, which gives it low orchestration overhead. Project-published benchmarks compare it favorably with Airflow, Prefect, and Temporal on lightweight and sequential workflow tasks. Scripts can be written in Python, TypeScript, Go, PHP, Bash, C#, SQL, Rust, or run inside arbitrary Docker containers.

The platform works at three levels: individual scripts get automatic parameter parsing and UI generation so any function becomes a shareable tool; flows compose scripts into multi-step workflows with branching, retries, error handling, and approval steps via a visual editor or YAML; and the app builder creates data-centric dashboards and internal tools using drag-and-drop components or full React/Svelte code. Local development is supported through a CLI and VS Code extension that sync with Git repos, and workspace forks enable parallel teamwork with built-in diffs and audit trails before merging to production. Sandboxing uses nsjail for filesystem and PID namespace isolation to prevent jobs from accessing worker memory.

Self-hosting uses Docker or Kubernetes backed by PostgreSQL, with scaling from small deployments to larger worker groups. The public pricing page keeps free/open-source self-hosting separate from Enterprise, which starts at $120/month and adds SSO/SAML, Git sync, audit logs, dependency caching, security controls, and dedicated support. The raw license file is nuanced: source is variously Apache-2.0 or AGPLv3, while certain Community Edition and enterprise features include proprietary or non-public terms that commercial teams should review.

Pricing

Free/open-source self-host path. Enterprise from $120/mo; worker/compute pricing depends on deployment.

Platforms

Rust backend, Docker/Kubernetes, PostgreSQL, VS Code extension, CLI

Categories

Tags

Use Cases

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Open-source background jobs and AI workflows for TypeScript

Trigger.dev is an open-source platform for building and deploying background jobs, AI agents, and long-running workflows in TypeScript. It eliminates serverless timeouts with durable task execution, automatic retries, queue-based concurrency control, and elastic scaling. Used by 30,000+ developers at companies like MagicSchool and Icon.com, it processes hundreds of millions of agent runs monthly. Backed by a $16M Series A led by Dalton Caldwell's Standard Capital fund.

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Run LLMs as a single portable executable file

Llamafile by Mozilla packages a complete LLM — model weights, inference engine, and OpenAI-compatible API server — into a single executable file that runs on Mac, Windows, Linux, FreeBSD, and OpenBSD with no installation. Built on llama.cpp and Cosmopolitan Libc for cross-platform portability, it delivers GPU-accelerated inference when available and falls back to optimized CPU execution. Supports GGUF models with a built-in web chat UI and REST API for integration.

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Comparisons

n8n vs Windmill — Visual Workflow Automation vs Code-First Developer Platform

n8n and Windmill are both open-source workflow automation platforms, but they serve different audiences. n8n provides a visual node-based workflow builder with 400+ integrations optimized for business automation and operations teams. Windmill is a code-first platform built for developers that executes scripts in Python, TypeScript, Go, and Bash with a visual flow editor, approval steps, and infrastructure-grade scheduling.

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FAQ

What is Windmill?

Windmill is an open-source workflow engine and developer platform built in Rust that turns scripts in Python, TypeScript, Go, Bash, SQL, and other languages into auto-generated UIs, API endpoints, workflows, data pipelines, AI agents, and scheduled jobs. The project publishes performance benchmarks against Airflow/Prefect/Temporal, supports Docker/Kubernetes self-hosting, and offers paid enterprise features.

Is Windmill free?

Windmill offers a free tier alongside paid plans. Free/open-source self-host path. Enterprise from $120/mo; worker/compute pricing depends on deployment.

Is Windmill open source?

Yes — Windmill is open source.

What are the best Windmill alternatives?

The top editor-verified Windmill alternatives are Trigger.dev, Llamafile, AnythingLLM.

How does Windmill score in our review?

Our hands-on review scores Windmill 84/100 overall, based on speed, privacy, and developer-experience testing.