Gong offers both Basic auth (API key) and OAuth as authentication. Nango implements both. To register an OAuth app, you need to request a developer account. At first, the OAuth app will be private (only for test) and you need an additional approval to make it public.
End users can generate API keys on the Gong API page. They must have the “technical administrator” user role to do this.
Gong uses BASIC auth for their API, but doesn’t call them username and password: Access Key is the username in Nango and Access Key Secret is the password in Nango.
Gong rate-limits are per second and a total of 10k requests a day.