post https://www.formstack.com/api/v2/oauth2/token
Once a user has authorized the client application and they are redirected, the client application can use the token endpoint to get an access token. Access tokens are then used to access protected resources.
Retrieve an authorization token for the specified authorization code
POST /api/v2/oauth2/token HTTP/1.1
Host: www.formstack.com
client_id=1234&redirect_uri=http%3A%2F%2Fwww.example.com&client_secret=abcdefg&code=123456&grant_type=authorization_code
curl -X POST -i -d "client_id=1234&redirect_uri=http%3A%2F%2Fwww.example.com&client_secret=abcdefg&code=123456&grant_type=authorization_code" https://www.formstack.com/api/v2/oauth2/token
To request an OAuth2 token to use with the Formstack API explorer, visit here.