Workato

Workato is a strong match for the Retool concept. It offers a comprehensive integration and automation platform that enables users to connect various applications and data sources, automate workflows, and build AI-powered solutions. While it doesn't explicitly mention a 'drag-and-drop UI builder' for internal tools in the same way Retool does, it focuses heavily on workflow automation, API management, and AI integration, which are core aspects of building internal applications. The platform emphasizes low-code/no-code capabilities for building integrations and automations, and it supports extensive connectivity, security features, and flexible deployment options. The 'Low Code Apps' section suggests a UI building capability, but it's not as prominently featured as a general-purpose UI builder for internal tools.