Windmill is an open source developer platform for running scripts and orchestrating workflows that turns code written in Python, TypeScript, Go, PHP, Bash, or SQL into internal tools, scheduled jobs, and production pipelines with auto-generated UIs.
The Problem
Retool addresses the UI problem for internal tools but requires a no-code approach that limits what developers can express. Airflow addresses the pipeline orchestration problem but carries significant operational overhead and is not designed for fast ad-hoc scripting. Teams end up maintaining two separate systems for workflows and tools, or compromising on what each tool can actually do.
How Windmill Solves It
Windmill combines a script runtime, a workflow DAG engine, and an app builder in one platform. Write a Python or TypeScript script and Windmill generates a web UI from its function signature automatically. Chain those scripts into workflows with branching, error handling, and parallelism using a visual canvas. The same platform handles scheduled cron jobs, webhook-triggered pipelines, and manually triggered internal tools. AGPL licensed; self-host on a single VPS or scale to Kubernetes.
Key Features
- Multi-language script runtime for Python, TypeScript, Go, PHP, Bash, and SQL with dependency management
- Visual workflow builder for DAGs with sub-20ms step overhead and full branching support
- Auto-generated web UIs for any script based on function parameter types
- App builder with drag-and-drop widgets that bind to scripts and workflows as data sources
- Git-native workspace sync for version control and deployment automation
- Scales from a single VPS to 1,000-worker Kubernetes clusters with dedicated worker groups
Who It's For
Windmill is best for developer teams who need a single platform to replace Retool for internal tools, Airflow for orchestration, and ad-hoc script scheduling. It fits platform engineering teams who want code-first control over their automation infrastructure without operating multiple systems.
Compared to Retool
Unlike Retool, Windmill lets developers write full code in Python, TypeScript, or Go rather than configuring a visual builder. The same platform handles scheduled pipelines and workflow orchestration that Retool cannot express, with no per-seat pricing on the self-hosted edition.
