What to use to test API against JSON?

Question

API

There is an internal service under development with an API that uses JSON for requests/responses. What testing tool would you recommend?
Minimum requirements:
* Naturally, the request body editor;
* POST requests;
* support for cookies;
* not nailed utf-8 (there are requests in win-1251 encoding);
* the instrument cannot be online, because service does not stick out;
* Windows platform.

Answer 1

Unirest

Answer 2

You can try SOAP UI