Developer for ZohoCRM Leads - Auth API 2.0 (Token issue)

Developer for ZohoCRM Leads - Auth API 2.0 (Token issue)

Good day,

Trying to figure out a way to always have access to post data to modules.leads.

I managed to work this out using postman, but only using a self client code.

Would like to use a serverless function to push the data and it requires an auth token that has not expired.
Is this possible to get this token using only the client id, client secret?