You can test this API by making requests against a test graph instance. Use this:
Test Graph Instance
Test Account: testaccount
Test Graph Instance: testinstance
TestAPI Key: z8uAZQmeFwAjhgjciY.20b.LX8Oorwm9q.sDyndWMEp39vj4Ze
Please be mindful that test instances are reset frequently and have additional protections that prevent them from being overused.