Postman - The Collaboration Platform for API Development
Charles Proxy - HTTP proxy / HTTP monitor / Reverse Proxy
Insomnia REST - The most intuitive cross-platform REST API Client ð´
soapUI - SoapUI Pro is one of the most prominent API testing platforms around, allowing developers to quickly prototype the functions of their apps and get them to market with little hassle.
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.
Postwoman - An online, open source API request builder