Plasmic

Plasmic is a strong match for the Retool concept. It explicitly states its purpose as a visual development platform for building internal tools and web applications, emphasizing its low-code/no-code capabilities while allowing for code customization. It offers extensive integrations with various data sources and APIs, a drag-and-drop UI builder with pre-built components, flexible deployment options, and robust security features including access control and SSO. The platform also supports version control, audit logs, and responsive design, aligning well with both must-have and other features of the Retool concept.