Internal tools & data apps · Windmill Labs

Windmill

Open-source developer platform that turns scripts into APIs, workflows and internal UIs, an alternative to Retool plus Airflow.

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Windmill is a developer-first platform for turning scripts (Python, TypeScript, Go, Bash, SQL and more) into webhooks, scheduled workflows and internal UIs — positioned as an open-source alternative to both Retool for building UIs and Airflow-style orchestrators for running them. Its Community Edition, built without the enterprise feature flag, is AGPL-3.0 licensed and free to self-host with unlimited executions; the various language client libraries are separately Apache-2.0 licensed. A managed cloud and self-hosted Enterprise tier add SSO, audit logs, SAML/SCIM and priced compute (per developer seat plus per-worker charges). It earns its place with data teams by letting engineers script data pulls, transformations and write-backs and expose them as an app or scheduled job, without hand-building a full internal tool from scratch.

At a glance

Vendor Windmill Labs
Pricing model Free tier + paid plans
Free tier Yes
Deployment Cloud, Self-hosted
Open source Yes (AGPL-3.0 (Community Edition, without enterprise features))
Best for Engineering teams wanting a code-first, self-hostable alternative to Retool plus a workflow/orchestration engine.

Pricing

Free, unlimited-execution open-source self-hosted edition; Enterprise adds per-developer seats, per-worker compute and SSO, from a monthly minimum.

Plan Price Notes
Free / Open-source $0/month unlimited executions, self-hosted, up to 50 users, max 10 SSO users
Enterprise from $120/month $20/developer/month, $10/operator/month, $50/worker/month (2 CU minimum); uncapped SSO, SAML & SCIM

Prices read from the vendor's own page on September 21, 2026. Vendors change prices; check the source before you budget.

Features

  • Turns Python/TypeScript/Go/Bash/SQL scripts into APIs and workflows
  • Visual workflow/flow editor alongside code-first scripts
  • Auto-generated UIs and internal apps from scripts
  • Free, unlimited-execution open-source self-hosting
  • Distributed worker architecture for scaling execution
  • Scheduling, webhooks and event triggers
  • Audit logs and SAML/SCIM (Enterprise)

Integrations

Profile last reviewed September 21, 2026

Alternatives

Retool Drag-and-drop app builder for internal tools that read and write to databases and APIs, not an analytics product itself. Appsmith Open-source, self-hostable app builder for internal tools and admin panels, free to run at any scale. Budibase Open-source low-code builder for internal apps and automations, self-hostable free with paid cloud tiers for teams. ToolJet AGPL-licensed open-source low-code builder for internal tools, dashboards and, increasingly, AI agent workflows.

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Terms to know

Data pipeline The automated sequence of steps that moves data from source systems to a destination, transforming it along the way. Feature flag A configuration switch that turns a piece of functionality on or off, or for specific users, without deploying new code.

Related guides

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