Appsmith

Appsmith is the leading open-source alternative to Retool, with 34,000+ GitHub stars and a self-hosted deployment path that eliminates per-user licensing costs entirely. Covers the same internal tool use cases as Retool: admin panels, CRUD interfaces, dashboards, and ops workflows — with 45+ data source connectors (PostgreSQL, MySQL, MongoDB, S3, REST, GraphQL, Firestore, and more). JavaScript-first logic layer gives developers full control beyond drag-and-drop. Cloud plans start at $15/user/mo (Business). SOC 2 compliant on Business and Enterprise tiers. Best for engineering teams with data sovereignty requirements, teams on tight budgets who can manage their own infrastructure, and organizations where Retool's $50/user/mo Business plan is prohibitive.