HttpMaster - HttpMaster is a professional software tool for testing and debugging HTTP applications, primarily aimed at REST API applications and web services.
GitHub - Originally founded as a project to simplify sharing code, GitHub has grown into an application used by over a million people to store over two million code repositories, making GitHub the largest code host in the world.
MockServer - Easy mocking of any system you integrate with via HTTP or HTTPS.
GitLab - Create, review and deploy code together with GitLab open source git repo management software | GitLab
Request inspector - Debug web hooks, http clients
BitBucket - Bitbucket is a free code hosting site for Mercurial and Git. Manage your development with a hosted wiki, issue tracker and source code.