HyperTest is a no-code test automation tool that regresses all your APIs by auto-generating integration tests using your network traffic, also giving a way to reproduce these failures inside actual user-journeys.

Automate API workflows. Chain HTTP requests. Validate. Zero code.

Charles is a HTTP proxy that enables you to see traffic between your machine and the backend

Simulate APIs, integrations, and environments at enterprise scale.

Mock and modify HTTP request for exploratory testing.

Burp or Burp Suite is a set of tools used for penetration testing of web applications. It is developed by a company named Portswigger who make freely available a Web Security Academy which has a range of lessons on penetration testing.