Appsmith vs ToolJet vs Budibase: open-source internal tools for a Next.js SaaS (2026)

Quick answer (August 2026)

If you want an open-source internal tools builder to sit next to a Next.js SaaS in 2026, the shortlist is Appsmith, ToolJet, and Budibase. They are all self-hostable low-code platforms, the credible open-source answer to Retool, and the honest split is by license and by weight. Appsmith (Apache-2.0, 40.6k stars) is the most permissively licensed and the fastest way to wire a grid over your Postgres. ToolJet (AGPL-3.0, 38.3k stars) leans hardest into workflows and AI agents, but its copyleft license is the strictest of the three. Budibase (GPL-3.0 core plus a Business Source License on paid features, 28.2k stars) is the most opinionated app builder with a built-in database, though some of what looks open is source-available, not OSI-open. All star counts and licenses were read from each project's GitHub on August 3, 2026.

One thing to settle before you read further: these three are not the same kind of tool as Refine, React-Admin, or AdminJS. Those are React libraries you import into your own app. Appsmith, ToolJet, and Budibase are separate applications you run alongside your SaaS. That distinction decides almost everything else.

Why these three, and not a component library

A Next.js SaaS already owns its customer-facing UI. The internal tools question is different: your ops team needs to refund a charge, flip a feature flag, or moderate a record, and you do not want to hand-build a screen for every one of those. That is the job Retool made popular, and the job all three of these tools do without a per-seat bill you cannot self-host away from.

Because they are standalone platforms, you do not embed them the way you embed a library. You run them at something like admin.yourdomain.com, point them at the same Postgres your Next.js app uses (or at your API), and let your team log in there. The upside is that your production app stays lean and your back office ships in an afternoon. The tradeoff is a second service to host, upgrade, and secure. If you would rather keep everything inside one Next.js deploy, a component library is the better shape, and our React-Admin review covers that path.

At a glance (August 2026)

Appsmith: the permissive default

Appsmith describes itself as a "platform to build admin panels, internal tools, and dashboards" that "integrates with 25+ databases and any API," and at 40.6k GitHub stars it is the most-starred of the three (Appsmith on GitHub, read August 3, 2026). You drag widgets onto a canvas, bind them to SQL queries or REST calls, and write small bits of JavaScript where you need logic.

The reason we reach for it first in most Next.js back offices is the Apache-2.0 license. It is the most permissive of the three, which means the fewest questions from anyone reviewing what you can legally do with a self-hosted, possibly modified copy. Where Appsmith loses: its canvas is a grid-and-widget model, so highly custom layouts fight the tool, and complex multi-step automation is not its strength. It builds screens, not pipelines.

ToolJet: workflows and agents

ToolJet now positions itself as "the open-source foundation of ToolJet AI," an "enterprise app generation platform for building internal tools, dashboard, business applications, workflows and AI agents" (ToolJet on GitHub, read August 3, 2026). At 38.3k stars it is neck and neck with Appsmith on mindshare, and its distinguishing feature is a proper visual workflow builder plus first-class AI agent tooling, which the other two treat as secondary.

The catch is the license. ToolJet is AGPL-3.0, the strictest copyleft of the three. For most teams that self-host it internally and never distribute a modified copy, AGPL is fine. But if you plan to fork it, change it, and expose that modified version over a network to users outside your company, AGPL's network clause obliges you to share your changes. That is a real constraint worth naming before you commit, and it is why ToolJet also sells a commercial license. Where it loses: the extra power means more surface to learn, and a heavier deploy than a plain grid.

Budibase: batteries included

Budibase is the most opinionated of the three. It ships with its own internal database, so you can stand up an app with data even before you connect an external Postgres, and it describes itself around "AI agents, automations and apps that run your operations" (Budibase on GitHub, read August 3, 2026). At 28.2k stars it is the smallest community here but still a large, active project.

The license needs care. Budibase's core is GPL-3.0, its client and component libraries carry MPL, and its paid features sit under a Business Source License. BSL is source-available, not OSI-open, and it typically restricts commercial or competing use for a few years before converting to an open license. In plain terms: the free self-hosted Budibase is real and generous, but "Budibase is open source" is not true of the whole product the way it is for Appsmith's Apache core. Where it loses: connecting to a large existing schema is less frictionless than in Appsmith, because Budibase wants to be the center of gravity, not a thin layer over your data.

The license fork nobody tables

Most roundups stop at features. For an internal tool you self-host next to a commercial SaaS, the license is the part that actually bites, so here is the honest ladder, most permissive first:

• Appsmith, Apache-2.0: do almost anything, including host a modified copy, with minimal obligation.
• Budibase, GPL-3.0 core plus BSL on paid features: the core is copyleft, and a slice of the product is source-available rather than open. Read which features you actually need before assuming they are free.
• ToolJet, AGPL-3.0: the strongest copyleft. Safe for internal self-hosting, but the network clause matters the moment you distribute a modified, network-exposed version.

None of this makes ToolJet or Budibase a bad choice. It makes them a deliberate one.

How to pick

Reach for Appsmith when you want the least licensing friction and a fast table-and-form over data you already have. Reach for ToolJet when the internal tool is really a workflow, with approvals, scheduled jobs, or an agent in the loop, and you are comfortable self-hosting under AGPL. Reach for Budibase when you want the most finished single-app experience and are happy for the tool to own some of your data. If you would rather not run a separate service at all, skip the category and embed a component library inside your Next.js app instead, which is where our open-source Next.js SaaS starter scorecard can point you.

Your move: pick the license you can live with first, then the weight, because on features these three are closer than any comparison table makes them look.