You can use a custom OAuth app to authenticate with a service account or a user account. See Using OAuth Authentication for more information.

Desktop Authentication with a Custom OAuth App

Get the OAuth Access Token

After setting the following, you are ready to connect:

• OAuthClientId: Set this to the client Id assigned when you registered your app. You can find it by visiting trello.com/app-key under API Key
• OAuthClientSecret: Set this to the client secret assigned when you registered your app. You can find it by visiting trello.com/app-key scrolling to the bottom
• CallbackURL: Set this to a localhost callback such as http://localhost:33333. If left empty, the Trello Adapter will default to http://localhost:33333.
• InitiateOAuth: Set this to GETANDREFRESH. You can use InitiateOAuth to avoid repeating the OAuth exchange and manually setting the OAuthAccessToken.

When you connect the adapter opens the OAuth endpoint in your default browser. Log in and grant permissions to the application. The adapter then completes the OAuth process:

1. Extracts the access token from the callback URL and authenticates requests.
2. Saves OAuth values in OAuthSettingsLocation to be persisted across connections.