Windmill

What Windmill is

Windmill is an open source platform for building and orchestrating internal software. Its home page puts it as one platform to build, share and orchestrate scripts, workflows, internal apps, data pipelines, AI agents and scheduled tasks, with the governance and observability needed at enterprise scale. It is written for developers first, but the pitch covers every team that now builds custom apps and workflows: engineering, data, sales, support and marketing. You can self-host it, and the site also offers Windmill Cloud.

The company states it is trusted by 4,000+ organizations, including 300+ Enterprise Edition customers at scale.

What you build and how

Scripts. The home page calls scripts "the starting point for most internal work". A single file of TypeScript, Python, Go, Bash or 20+ other languages becomes an API, a triggerable job and an auto-generated form, with no boilerplate in between. There are no custom or proprietary SDKs. The company's principle is "normal code in mainstream languages": you run it locally, generate it with LLMs and port it anywhere.

Flows. Windmill's comparison pages describe flows as state machines represented as DAGs that compose steps into workflows and ETLs. Each step can be forked from a script on the community Hub, saved as a separate script in your workspace, or written directly in the integrated code editor. The comparison with Retool lists approval steps, early stop and sleep among the flow features, and approval steps pause a flow until someone approves it. That makes human sign-off a normal part of an automation instead of a bolt-on.

Internal apps. Windmill has a low-code app editor and also supports full-code apps in React or Svelte that call Windmill backend runnables. The comparison with Retool calls its app builder "very similar" to Retool's drag-and-drop one, and says the script and flow editors are what take you further. The platform generates the UI for script and flow input fields automatically, so a script turns into a form without front-end work. A separate option, which the company describes as a custom platform and pricing for operators, lets people only trigger flows rather than edit them.

Editors and local work. You can build in the browser with the built-in script editor, flow editor and app builder, or locally. The CLI installs with npm install -g windmill-cli, and you deploy to a remote workspace with wmill sync push. The site mentions built-in AI skills for building locally with Claude Code or Codex. The developer tools also include git sync for version control, a VS Code extension, support for JetBrains IDEs and deployment from GitHub or GitLab.

Data, secrets and observability. The comparison pages list reusable variables, secrets and resources, plus built-in worker logs and metrics. The home page lists Rest and GraphQL support next to its language support. For the Pave case study the page says the deployment talks to half a dozen data stores.

Scale. The home page says Windmill can auto-scale on demand or isolate critical tasks with dedicated worker groups on Kubernetes and Docker. In the company's own benchmarks against Kestra, Windmill in normal mode is slightly faster, and in dedicated worker mode it is 3x faster. The company wrote that comparison itself, and its page says so.

Integrations and the Hub. Windmill has "dozens of integrations" that the community initiated and the Windmill team approved, and it provides a framework so that anyone can add one in a few clicks. A public community Hub holds scripts, flows and apps that users share. The most relevant ones are marked as Approved by the Windmill team and built into the product.

Open source and self-hosting. The comparison pages state that Windmill is fully open source and can be self-hosted with a few commands, in 2 minutes or 3 minutes depending on the page, through Docker Compose. The core principles on the home page say "No lock-in. Open source and self-hostable. Your code, your data, your infrastructure." The site does not name the license on the pages.

Plans, pricing and evidence

The company describes a "transparent pricing policy". Every feature the comparison pages mention is free unless it is marked EE for Enterprise Edition, and the page points to a Pricing page for the Enterprise Edition features and the subscription plans. The pricing page itself is not among the pages read for this entry, so no plan names or prices appear here. Windmill states that it is cheaper at scale and can be used for free at any scale thanks to its open source nature. The Kestra comparison notes that, as of November 18, 2024, Kestra does not disclose its Enterprise pricing.

The home page offers "Try Windmill cloud" and "Self-host in 3 mins", and it links video tutorials: Script Editor (11 min), Flow Editor (17 min), App Editor (6 min) and Local Development (3 min), with a 2-minute tour for people short on time.

Customer quotes on the home page show how teams use it:

• Photoroom self-hosted Windmill Enterprise Edition to run a large number of internal scripts and business-critical automations, and its co-founder and CTO says it made chatops and iterations over scripts incredibly easy.
• Pave self-hosted Enterprise Edition to run 100+ scripts and 15+ crons, and the quote says this keeps things secure and avoids infrastructure sprawl.
• Investing.com uses Windmill to orchestrate AI workflows, covering content processing pipelines, automated stock analysis report generation and ETL processes, and says Docker Compose made the setup quick.
• A further customer reports 9 apps, 20 flows and 63 scripts in daily operation.

These are the company's chosen testimonials, not an independent survey. The pages do not state a compliance certification, a hosting region or support plan terms.

Who it suits and who it does not

Windmill suits a team with engineers who would rather write Python, TypeScript or Bash than learn a drag-and-drop dialect, and who want the result to show up as an API, a form, a scheduled job or an internal app. It fits a platform or data team replacing scattered cron jobs and scripts, and an enterprise that wants to self-host and keep the code in its own infrastructure. The git sync and CLI make it workable inside an existing review process.

It is a different bet for a non-technical operator. The Retool page admits that Retool has a vast library of templates and a broad library of components, and Windmill answers with the Hub instead. The core unit is a script, so someone has to write or fork one. A solo founder who wants a point-and-click storefront or a no-code database will find the product aimed at someone else. Running it yourself also means you operate the servers, which is the trade for no lock-in, though Windmill Cloud is there for teams that would rather not.