There are many tools available in the market for API monitoring and testing. What to choose totally depends on what you want to achieve through those tools. Some tools provide great support for performance monitoring, and other tools are better suited for quality testing and recognizing erroneous data.
Some popular tools are as follows:
- Karate DSL
- REST Assured
You can read more about the benefits of, and support for, these tools on their respective sites and choose the tools best suited to the project's needs.