Internal tools are the software nobody demos and everybody depends on: the admin panel that refunds an order, the dashboard that shows which jobs are stuck, the form that lets support edit one field without opening a database client.
Retool made building those fast. It also prices them per builder and per viewer, and its own self-hosted option sits on the Enterprise tier. This post is about the three open-source builders you can run yourself instead, and about the property that actually decides whether that goes well.
Why people leave
Retool has a free tier for up to five users. Above that, Team is €9 per builder and €5 per internal user per month, Business is €46 per builder and €14 per internal user, and Enterprise is quoted per organisation. There are separate rates for external users on Business.
Two things push teams to look elsewhere. The first is that the viewer count grows: internal tools spread, and every person who needs to click one button is billed. The second is that self-hosting - the usual answer when data cannot leave your network - is available on Enterprise, which means the conversation starts with sales rather than with a container.
The three worth knowing
Appsmith is the closest in spirit to Retool: drag widgets onto a canvas, bind them to queries, ship an admin panel in an afternoon. It has 40.7k stars and is Apache-2.0, the most permissive licence of the three. Note the image name you deploy is appsmith-ce, the community edition, which tells you upfront that some features live in a paid edition.
ToolJet is the closest competitor by size at 39k stars, licensed AGPL-3.0. AGPL is a real consideration if you plan to modify it and expose it to users outside your organisation, and irrelevant if you are running it unmodified for your own team.
Budibase has 28.2k stars and the most complicated licensing answer of the three. Its own guidance says each package carries its own licence and that you can "consider Budibase to be GPLv3 licensed overall", and it ships a component, Structured Query Server, under a separate licence again. It also leans further towards building internal applications with their own data than towards putting a panel over a database you already have.
The shape matters more than the feature list
Every comparison of these tools argues about widgets. Having packaged all three, the difference that shows up later is structural, and you can read it off the container list.
Appsmith and Budibase each ship as a single container with everything inside. Appsmith runs as one image with one volume holding its stack; Budibase does the same with its own volume. The databases, cache and web server those products need still exist, they just live inside the container rather than beside it.
ToolJet ships the other way: an application container, a Postgres of its own, and a Redis, with the database in its own volume.
This is invisible on day one and decisive on day ninety. When your internal tools live in a single opaque volume, a backup is a copy of a directory that contains a database mid-write, and restoring it is a hope rather than a procedure. When the database is a Postgres you can see, backups are the same boring thing you already do for everything else, and upgrading the application does not mean upgrading its hidden datastore at the same time.
Neither shape is wrong. The bundled ones are genuinely easier to start. But if these tools are going to hold anything you would miss, the shape of the deployment is worth more attention than the widget library.
What it costs to run
All three are a single plan's worth of compute, not a per-seat line item. The bill stops growing when you add the fifth person who needs to look at one dashboard.
Our catalogue ships all three, each pinned to a specific release rather than latest, so a redeploy gives you the version you tested. On a flat plan starting at $5 a month they sit alongside whatever else you run, which is usually the point: internal tools are rarely the only thing a team self-hosts.
The part self-hosting does not replace
Retool's value is not only the canvas. It is the connectors that keep working when a third-party API changes, the access control that someone else maintains, and the fact that an internal tool breaking at 9am is somebody's job to fix.
Self-hosted, that is your job. The honest version of the trade is that you are exchanging a per-seat bill for an operational responsibility, and the exchange is a good one mostly when the seat count has grown past the point where the responsibility costs less than the invoice.
When to stay
Stay on Retool if you are under the five-user free tier, if the connectors you rely on are the reason the tool works at all, or if the people building the tools are not the people who would keep a database alive. Team pricing is genuinely reasonable for a small group of builders.
Move if the viewer count is what is growing, if the data behind these tools cannot leave your infrastructure and you do not want an Enterprise conversation to solve that, or if you already operate a Postgres and adding one more service is not a new category of work for you.
Frequently asked questions
Can I self-host Retool itself? Yes, but their pricing page lists self-hosting under Enterprise plans, which are custom-quoted. If self-hosting is a requirement rather than a preference, that is usually what sends teams to the open alternatives.
Which one is the most like Retool? Appsmith, both in how the builder feels and in how quickly someone who knows Retool becomes productive.
Which licence is the safest for a company? Appsmith under Apache-2.0 asks the least of you. ToolJet's AGPL-3.0 matters if you modify it and expose it externally. Budibase requires reading, because the answer is per-package.
Do they connect to my existing database? All three do. That is the core use case for Appsmith and ToolJet in particular: a panel over data that already exists somewhere.
What do I actually need to run one? Appsmith and Budibase are one container and one volume each. ToolJet is three containers, with its Postgres and Redis alongside. Any small instance runs any of them for a team-sized workload.