GET /me. Call it whenever you install or rotate a key.
The path sits under the test base path
/api/trading/test/v1 or the production base path /api/trading/v1. Both return the same object; the test path takes a test key and the production path a live key (see Test and production).
The account object
Read your account
200 OK
production_trading_available is the same on the test and production paths, so you can check it with either key before you send a real order. See Production access requirements.
Errors
The account call shares the refusals of every call. The ones you will meet most:
The full list is in Errors.