Charles Proxy - HTTP proxy / HTTP monitor / Reverse Proxy
BitBucket - Bitbucket is a free code hosting site for Mercurial and Git. Manage your development with a hosted wiki, issue tracker and source code.
Wireshark - Wireshark is a network protocol analyzer for Unix and Windows. It lets you capture and interactively browse the traffic running on a computer network.
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.
Postman - The Collaboration Platform for API Development
GitLab - Create, review and deploy code together with GitLab open source git repo management software | GitLab