Is Windmill a drop-in replacement for Retool?

For the internal-apps use case, yes, with caveats. Windmill has a visual app builder with a component library similar to Retool's, plus a full-code option in React or Svelte that Retool does not offer. Porting involves rebuilding apps component by component, since Retool's canvas definition is proprietary and not directly importable. Teams that lean heavily on Retool's richer widget catalog (mobile-specific components, some specialty inputs) should audit component parity before committing to a migration.

Can I migrate Retool apps to Windmill automatically?

No. Retool apps are stored in Retool's proprietary canvas format and there is no official export to an open format. Migrations are manual rebuilds, where each query becomes a Windmill script and each component maps to the closest Windmill equivalent. Because Windmill scripts run as standalone primitives with their own API endpoints, many of the queries you rebuild can be reused outside the app (as webhooks, scheduled jobs, or flow steps), which was not possible inside Retool.

Is Retool open source?

No. Retool is a proprietary, closed-source product. Self-hosting is available only on the Enterprise plan. Windmill, by contrast, ships an AGPLv3 open-source core that is free to self-host without a sales conversation, with Enterprise features in a separate proprietary codebase.

Does Windmill support JavaScript and SQL queries the way Retool does?

Yes, and more. Windmill scripts can be written in TypeScript, JavaScript, Python, Go, Bash, SQL, PHP, Rust, C#, and any Docker container. Retool supports JavaScript inside apps and a mix of JavaScript and Python inside Workflows, which covers the common cases but is narrower than Windmill's language range. For SQL specifically, both platforms let you write raw queries against connected databases.

Is Retool better for non-technical users who want to build apps?

Retool is more polished for that audience on the app-building side: a deeper component library, more mature drag-and-drop interactions, and a UX that assumes no CLI or Git. Windmill has a visual app builder too, but authoring queries still involves writing code. If your primary users are business analysts assembling CRUD UIs over a single database, Retool is often faster to stand up. If the team is developer-led or needs to ship code-driven automations alongside apps, Windmill fits better.

How does pricing compare?

Retool charges per user: builders at around €46/month on the Business plan (end users at €14/month), with SSO, Git sync and self-hosting only on Enterprise (custom pricing). Windmill is free and unlimited to self-host for up to 10 SSO users and 3 workspaces, with published per-seat and per-worker Enterprise pricing starting at $120/month. For larger teams the cost difference can be substantial, especially if most users are builders.

Can I self-host Retool the way I can self-host Windmill?

Not on the free or Team plans. Retool self-hosting requires an Enterprise contract. Windmill's open-source core is free to self-host at any scale: clone the repo, run docker compose, done. If self-hosting without a sales conversation is a hard requirement (for compliance, budget, or preference), this is often the single most decisive difference.

Windmill

Windmill cloud

OSS

Windmill vs Retool

Eight questions teams ask during a bake-off, with an honest answer on each one for where Windmill or Retool is the better pick.

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The 8 questions

01What you can buildWhich solution fits for your specific use case
02TargetWho the platform is built for
03Build experienceHow you build on each platform
04IntegrationsHow the platform integrates with your existing stack
05Migration & lock-inHow hard to get in, how hard to get out
06Enterprise requirementsAudit logs, observability, security, performance
07Licensing & pricingOpen source, pricing, self-hosting
08VerdictThe verdict

Windmill in one sentence

An open-source workflow engine and developer platform to build and orchestrate all your internal software: scripts, workflows, data pipelines, AI agents and internal apps. Made for engineers who want full code flexibility and local dev experience, both to build internal software and to manage the underlying infrastructure.

Retool in one sentence

A proprietary low-code platform for internal apps: drag-and-drop canvas, large component library, JavaScript queries on top of your databases and APIs, and AI-assisted app generation. Workflows and AI Agents are adjacent products on the same canvas.

01 · What you can build

Which internal software can you build and orchestrate?

Windmill centralizes scripts, workflows, data pipelines, full-code apps, AI agents and operator UIs on a single runtime, with shared resources, auth and observability. Retool is app-builder first, with Workflows and Agents layered on the same visual canvas. Strong for internal apps. Narrower for scripts-as-APIs, heavy data pipelines and code-first automations.

Primitive	Windmill	Retool
Low-code internal apps Drag-and-drop dashboards and admin tools with a built-in component library
Full-code internal apps Custom dashboards and admin tools built in React or Svelte
Workflows Chain steps into flows with branching, retries and approval steps
Scripts Standalone functions exposed as APIs, webhooks or cron jobs with their own UI
Data pipelines ETL, syncs and scheduled data jobs with parallel branches		Partial
AI agents with tool calling Build agents that call tools, branch on outputs and run as workflows
AI sandboxes & volumes Isolated environments with persistent volumes for running agents
Scheduled tasks Cron jobs with retries, error handling and alerting

02 · Target

Who is each platform built for?

Windmill is built for developer-led teams where engineers own the platform end-to-end. Retool is built for developers and low-code engineers who want a polished visual canvas for internal tools, with JavaScript and SQL for the glue logic.

Windmill

Retool

Primary audience

Windmill

Developer-led teams. Engineers own the platform end-to-end: code, Git, local dev, workspace forks, code review, CI/CD, AI coding tools, infrastructure as code.

Retool

Developers and low-code engineers building internal tools. The canvas-first UX is designed for people who think visually and write short JavaScript or SQL for glue logic. Common audience: full-stack devs, data engineers, ops engineers, technical PMs.

How non-developers participate

Windmill

Non-developers consume through auto-generated UIs, custom apps and an operator role. They can build simple apps with AI assistance, but authoring scripts and flows still involves writing code.

Retool

The drag-and-drop app canvas is approachable for non-developers who can read a bit of JavaScript. Deeper flows and Workflows still require real code, so a purely no-code user hits a ceiling fast.

03 · Build experience

How do you build on each platform?

Windmill is code-first: scripts are real files in any of 20+ languages, runnable locally, and the whole workspace lives in Git. Retool is canvas-first: apps and workflows are built visually in a web IDE against live data, with JavaScript and SQL for glue code. Great for getting started fast, harder to treat like application code.

Windmill

Full IaC: scripts, flows, apps, resources, variables, secrets, schedules, folders, groups and permissions are all files in Git, deployed via the CLI and Git sync. Internal tooling runs like application code: PRs, reviews, rollbacks, CI/CD. Git sync is free for up to 2 users; beyond that is Enterprise only.

Retool

Retool Source Control syncs apps, workflows, resources and themes to GitHub, GitLab, Bitbucket, AWS CodeCommit or Azure Repos via pull requests. It is listed as Enterprise only on the pricing page. Lower tiers rely on App Release Versions inside Retool itself.

04 · Integrations

How does the platform integrate with your existing stack?

Windmill treats any public package (npm, PyPI, Go or Maven) or your own as a first-class import, so the effective integration catalog is the package ecosystems themselves. Retool ships 100+ polished connectors for the most common databases and SaaS tools. Easier out of the box for mainstream stacks. Tighter ceiling for the long tail.

Type `import stripe` in the script editor and run. Windmill detects the import, resolves the version and pins it in a per-script lockfile automatically. No venv, no pip install, no restart: the platform manages dependencies for you.

Windmill

Retool

Connecting out

Windmill

Any npm, PyPI, Go or Maven package is a first-class import with automatic per-script dependency resolution and lockfiles, and no plugin layer in between: you call the vendor's real SDK with full type inference and auto-completion in the editor. 50+ pre-built resource types cover common databases (Postgres, Snowflake, BigQuery), SaaS (Slack, Stripe, GitHub, Notion, OpenAI) and infrastructure (S3, Redis, Kafka): paste an API key into a typed form and the resource is shared across scripts, flows and apps, encrypted at rest. A community Hub has reusable scripts and flows for common tasks.

Retool

80+ pre-built connectors for databases (Postgres, MySQL, Snowflake, BigQuery), SaaS (Salesforce, Stripe, HubSpot, Slack, Zendesk, Jira) and AI providers (OpenAI, Anthropic, Google Gemini). For anything not in the catalog, you fall back to a generic REST or GraphQL resource or a JavaScript code block.

Receiving events

Windmill

Native triggers for HTTP, cron, Kafka, NATS, Postgres CDC, SQS, MQTT, SMTP and WebSocket. Each trigger is a typed primitive in the UI: configure topic, subject or path, attach it to a script or flow, and Windmill handles the connection, replay and consumer-group state. Every script also gets an HTTP endpoint and a webhook URL for free, so most receive paths need zero glue code.

Retool

Three trigger types on Workflows: Scheduled (cron), Webhook, and Query (BETA, polls a database or SaaS query for new rows). Event-driven triggers beyond that (Kafka consumers, CDC, queue consumers) require polling workarounds or an external event bridge.

Extending

Windmill

A new integration is just a script with a new import. No plugin release cycle to wait on. Custom UI components can be added as React components.

Retool

Custom components exist but are limited compared to writing a standalone React app. Custom auth, custom connectors and advanced integrations often require dropping to a generic REST resource with hand-rolled JavaScript transformers.

05 · Migration & lock-in

How hard to get in, and how hard to get out?

Windmill keeps switching cost low. Step code is standard TS, Python, Go, Bash or SQL that runs anywhere, including after you leave Windmill. Retool has higher lock-in: apps are stored in a proprietary canvas format, and Git export is an Enterprise feature that still produces Retool-specific files.

Windmill

Retool

Getting in

Windmill

Paste a function body into the script editor, Windmill infers args, generates a UI, handles dependencies. Drag-and-drop apps, triggers, schedules and variables migrate one by one. No learning curve around a proprietary canvas format.

Retool

Fast if you already think in terms of drag-and-drop apps wired to queries. Common CRUD UIs over a database can be live in under an hour. Migrating existing code-based internal tools usually means redrawing the UI component by component, since there is no import from React, HTML or other app formats.

Getting out

Windmill

Step logic is already standard code (TS, Python, Go, Bash, SQL) that runs anywhere. The CLI exports the full workspace as plain files. What you lose leaving Windmill is the runtime, not the step code.

Retool

Retool apps are stored in a proprietary canvas format. With Source Control enabled (Enterprise only), apps and workflows sync to Git as JSON, but the format is Retool-specific and not portable to another platform without a rewrite. JavaScript and SQL inside queries are portable; the visual layout and component bindings are not.

06 · Enterprise requirements

Windmill

~10ms cold starts. Dedicated-worker mode Enterprise only keeps runtimes and dependencies pre-warmed. Published benchmarks against other orchestrators.

Retool

Performance is dominated by query and rendering time in apps, and by block startup in Workflows. No published performance benchmarks. Workflow runs are capped at 5,000/month on Team and Business. Higher volumes require Enterprise.

07 · Licensing & pricing

Open source, pricing, and self-hosting?

Windmill is open source (AGPLv3 core), free to self-host at any scale, with public per-seat and per-worker Enterprise pricing. Retool is proprietary and closed-source, priced per user. Self-hosting and most governance features require an Enterprise contract.

Windmill

Retool

Open-source license

Windmill

AGPLv3 core, free and unlimited self-hosted. Enterprise features (SSO, dedicated workers, audit logs, external secret backends) ship in a separate proprietary codebase. Managed cloud available.

Retool

Proprietary and closed-source. There is no open-source edition. Self-hosting is Enterprise only. Free, Team and Business plans are cloud-only.

Enterprise pricing

Windmill

Public per-seat and per-worker pricing on the pricing page, starting at $120/month. Enterprise adds SSO, audit logs, dedicated workers, advanced worker groups.

Retool

Per-user pricing: builders at €9/Team, €46/Business, custom on Enterprise. End users at €5/Team, €14/Business. External-user tier available on Business+. Enterprise pricing not public. A sales conversation is required for custom SSO, Git sync, self-hosting and independent workspaces.

08 · Verdict

The verdict

Windmill and Retool answer the internal-app question with two different stances. Retool is a proprietary SaaS with a polished visual canvas, where apps, queries and component bindings live in Retool's database; authoring is browser-against-live-data, with a CLI in Labs for scaffolding. Windmill is an open-source AGPLv3 platform where apps are real React or Svelte source trees in your repo, scripts and flows are files in Git, and the whole workspace runs on infrastructure you control.

Retool can be a good fit if your internal-tool need is a drag-and-drop dashboard on top of a database or SaaS API, your team is comfortable authoring inside the canvas, and a proprietary runtime is acceptable. The component library is broader and more mature than Windmill's, the visual editor is more refined for non-developer authors, and AI-assisted app generation lands quickly on mainstream patterns.

Windmill matches the same low-code surface and adds a full-code React or Svelte option that Retool does not offer, with a real local-dev loop: edit apps and the backend scripts and flows that power them in your IDE, with native language tooling and AI coding tools working against real source files, then deploy via the CLI or whole-workspace Git sync. The runtime scope is wider too: the same platform that runs your apps also powers workflow orchestration, data pipelines, scripts as standalone APIs and AI agents, with shared auth, secrets and observability across all of them. The core is AGPLv3 and free to self-host without an Enterprise contract, and Enterprise pricing is published upfront on the pricing page.

The switching cost is also asymmetric. Retool apps live in a proprietary canvas format with no official export, so leaving Retool means rebuilding each app component-by-component, with queries and event handlers rewritten against another runtime. Windmill apps and scripts are plain source files in Git, so the per-app rewrite cost is much smaller, and the Git history travels with you. If you're deciding between the two, the fastest way to judge is to spend an afternoon in each.

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