Lowdefy

Lowdefy is a full-stack web framework that enables developers to build web applications, internal tools, admin panels, and BI dashboards using YAML or JSON configuration files. It leverages Next.js for performance and deployment flexibility, integrates with Auth.js for comprehensive authentication and access control, and supports extensibility through npm and pnpm workspace plugins for custom code and components.

Lowdefy is a strong match for Retool's concept. It explicitly states its purpose is to build web applications, internal tools, admin panels, BI dashboards, and CRUD apps using YAML or JSON configuration files. It offers extensive integrations with various databases and APIs ('Connections' section), allows for custom code through plugins ('Plugin extensibility' and 'Extensibility with npm and pnpm workspace plugins'), and provides robust access control and security features via Auth.js integration, including role-based access control (RBAC). Lowdefy also highlights flexible deployment options due to being built on Next.js and supports mobile responsiveness. While it doesn't have a drag-and-drop UI builder in the same visual sense as Retool, it uses a 'config webstack' with 'blocks' which serve a similar component-based UI building purpose, albeit through configuration files. The 'Partner & Customer Portals' feature is also supported through its ability to build secure, white-labeled apps with fine-grained permissions.