Here a document link : https://www.cisco.com/c/en/us/td/docs/security/firepower/620/api/REST/Firepower_Management_Center_REST_API_Quick_Start_Guide_620.html    In case you want to validate JSON data you can use https://jsonformatter.org or https://co...

I found HMAC Generator tool helpful to test and generate HMAC data based on key and algorithms. 

Good to know this. regarding JSON, I was facing some issue. so I used JSON Formatter to resolve that.