How do I create solution categories using API?

You can use the following curl command : 

curl -u user@yourcompany.com:test -H "Content-Type: application/json" -X POST -d '{ "solution_category": { "name":"API", "description":"API related documents" }}' https://domain.freshservice.com/solution/categories.json

For more information, please click: 

https://api.freshservice.com/#create_solution_category