For a long time I used Paw, which became RapidAPI a couple years ago. Nice little app that does it's job well.
Lately I've just been using a Phoenix LiveBook notebook, with the Req package loaded into it. I can make requests, do arbitrary transforms on the data, and generally stay right at home in a language I like and understand
If you don't know elixir, I'm sure jupyter or some other notebook system would do just as nice of a job