WSO2 API Manager - WSO2 API Manager is a 100% open source enterprise-class solution that supports API publishing, lifecycle management, application development, access control, rate limiting and analytics in one cleanly integrated system.
swagger.io - Swagger is an open source RESTapi Documentation Tool.
Fusio - Open source API management platform
Optic - Automate routine programming
apiman - Open source API management
ng-docx - Ng-docx is a library that automatically generates a documentation page to easily and beautifully view your markdowns.