Charles vs Newman: What are the differences?
What is Charles? HTTP proxy / HTTP monitor / Reverse Proxy. Charles is a web proxy (HTTP Proxy / HTTP Monitor) that runs on your own computer. Your web browser (or any other Internet application) is then configured to access the Internet through Charles, and Charles is then able to record and display for you all of the data that is sent and received.
What is Newman? CLI collection runner for Postman. Newman is a command-line collection runner for Postman. It allows you to effortlessly run and test a Postman collection directly from the command-line. It is built with extensibility in mind so that you can easily integrate it with your continuous integration servers and build systems.
Charles and Newman can be primarily classified as "API" tools.
Newman is an open source tool with 3.67K GitHub stars and 524 GitHub forks. Here's a link to Newman's open source repository on GitHub.