Appsmith

Appsmith builds internal apps the same way Retool does: a widget library of tables, forms, and charts bound to queries against Postgres, MongoDB, REST APIs, and a long list of other connectors, with JavaScript available inline wherever the visual layer isn’t enough. Because it’s open source, teams can self-host it on their own infrastructure for free and only pay for the managed cloud version if they’d rather not run it themselves.

The free self-hosted tier has no seat cap, which is the main draw over Retool for a team with many internal users, while Appsmith’s paid cloud plans price by user like the rest of the category. App definitions export as JSON you can move between Appsmith instances, though there’s still no path to a standalone codebase outside the platform. The ceiling shows up in polish, the widget library and editor feel rougher than Retool’s, and enterprise features like fine-grained audit logs came later. It suits budget-conscious engineering teams who want the internal-tool pattern without a growing per-seat bill.