Appsmith vs Windmill
Both are alternatives to Retool. Here's how they stack up — verified facts, no spin.
Also searched as Windmill vs Appsmith — same comparison, one verdict.
Appsmith and Windmill are closely matched on ownership (90 vs 88) — this one comes down to pricing and to which trade-offs below you can live with.
Appsmith
TOP PICKThe closest open equivalent — drag, drop, connect, self-host.
Appsmith is the most direct open replacement for Retool: a drag-and-drop builder with widgets, JavaScript anywhere, and connectors for the major databases and APIs. It self-hosts with Docker or Kubernetes and the core is Apache-2.0, which is the most permissive licence of the serious options here. Around 40.6k stars. If your reason for reading this page is per-builder pricing, this is the first thing to try, and the conceptual jump from Retool is small enough that an existing Retool user is productive quickly.
Windmill
For teams whose internal tools are mostly scripts and workflows.
Windmill takes the opposite approach to a drag-and-drop canvas: you write scripts in Python, TypeScript, Go or Bash and Windmill generates the UI from their inputs, alongside a workflow engine for chaining them. For an engineering team whose internal tooling is fundamentally automation with a form on top — reruns, backfills, ops jobs — that is a much better fit than a widget canvas. AGPL-3.0 core with a commercial enterprise edition. Roughly 17.5k stars, and unusually fast because the execution engine is Rust.
Side by side
10 points of comparison, every one read from a verified field. Green marks the side that wins a row outright. A dash means we do not hold that fact — never that it is zero.
| Appsmith | Windmill | |
|---|---|---|
| Sovereignty ScoreOur transparent 0–100 composite for data ownership and exit cost. | 90 | 88 |
| Open source | Yes | Yes |
| Self-hostable | Yes | Yes |
| Local-first data | Yes | Yes |
| License | Apache-2.0 (core; some enterprise features are commercial) | AGPL-3.0 (core; enterprise edition is commercial) |
| Pricing | Free and open source to self-host. Paid cloud and enterprise tiers. | Free and open source to self-host. Paid cloud and enterprise editions. |
| RAM to run it wellThe figure that actually matters, not the vendor's minimum. | 8 GB with 2 vCPU. That is Appsmith's own baseline for standard deployments, which it describes as an entry point for pilots and low traffic rather than a production guarantee | — |
| Realistic running costWhat the box costs each month if you run it yourself. | $24–48/mo on an 8 GB VPS. MongoDB, Redis and PostgreSQL run inside the one container, so nothing else is required | — |
| Setup timeHonest first-install estimate, not the marketing quickstart. | 20 minutes to a working instance; an hour with a domain, HTTPS and a scheduled backup | — |
| Ongoing maintenanceThe part nobody budgets for. | The vendor recommends updating every two weeks on a pinned tag, with nightly appsmithctl backups stored off the box. Backups are encrypted with a password you must not lose; Appsmith says a forgotten password makes the backup impossible to restore. | — |
Appsmith is Macrostack's recommended Retool alternative, so it's our pick here.
Weighing both against staying on Retool? Is Retool free? What it actually costs →
Appsmith
Strengths
- +Closest feature match to Retool of anything open
- +Apache-2.0 core — the most permissive licence among serious options
- +Self-hosts on Docker or Kubernetes with no per-builder fee
- +Large widget library and broad database connector support
Trade-offs
- −Some governance and SSO features sit behind the paid tier
- −Fewer third-party integrations than Retool out of the box
- −You now operate a service, including upgrades and backups
- −Polish trails Retool in places, particularly complex state
Windmill
Strengths
- +Script-first: the UI is generated from code you already write
- +Serious workflow engine, not an afterthought
- +Rust execution engine — genuinely fast
- +Fits engineering teams better than a drag-and-drop canvas
Trade-offs
- −Wrong shape if you want non-engineers building tools
- −AGPL-3.0 strong copyleft
- −Smaller community than Appsmith or ToolJet
- −UI generation is less flexible than hand-placed widgets
Which one fits you
The trade-offs above, turned into a decision. Find the line that describes your team.
Choose Appsmith
if a lower exit cost matters more to you than any single feature, and closest feature match to Retool of anything open.
Choose Windmill
if script-first: the UI is generated from code you already write.
Neither, yet
if both carry a real cost you should weigh first — some governance and SSO features sit behind the paid tier, and wrong shape if you want non-engineers building tools. If either of those is a dealbreaker for your team, the shortlist is wrong rather than the choice.
What it takes to run these yourself
Real requirements and honest running costs, not the vendor quickstart.
Appsmith vs Windmill — common questions
Is Appsmith a better fit than Windmill for internal tools & admin panels?
It depends on what you are optimising for, and the honest split is this: Appsmith scores 90 to Windmill's 88 on data ownership and exit cost, so it is the safer choice if you care about being able to leave. Windmill earns its place on a different axis — script-first: the UI is generated from code you already write. Neither is a wrong answer for every team; the table above is the actual comparison.
What happens if we want to switch later?
Appsmith keeps its data local or in open formats, so leaving is an export rather than a negotiation. Windmill is still self-hostable, so the files stay on your server either way — but it is not local-first by design, so check what its export produces before you rely on it.
Can I self-host Appsmith or Windmill?
Both can be self-hosted. The difference is what it costs you in time rather than whether it is possible — see the setup and maintenance rows above.
Are Appsmith and Windmill both alternatives to Retool?
Yes — both appear in our Retool comparison, which is why they are worth putting side by side. People usually arrive here already having decided to move off Retool and now choosing between the two replacements, which is a narrower and much easier question.
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Facts verified 2026-08-07. Licenses and pricing change — spotted something out of date? That's a correction we want.