Grant domain-wide delegation and scopes

Authorize your Tantra service account in the Google Admin console with the exact OAuth scopes needed to send email and calendar invites.

intermediate5 min readUpdated Sat Jul 25 2026 00:00:00 GMT+0000 (Coordinated Universal Time)

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Overview

Domain-wide delegation is the permission that lets your Tantra service account act on behalf of the mailboxes in your Google Workspace domain. You grant it once, in your own Google Admin console, by authorizing the service account's client ID with a specific list of OAuth scopes. This article gives you the exact scopes to paste.

Before you start

  • You must be a Google Workspace super administrator.
  • You need the service account's client ID (a long numeric string). See Create a Google service account.
  • Decide which engines you will use. Cold email needs the Gmail scopes. Calendar campaigns need the Calendar scope. Grant both if you plan to use both.

The scopes to grant

Copy these values exactly. Each is a full URL and must be entered as shown.

For cold email (the Gmail API):

https://www.googleapis.com/auth/gmail.send
https://www.googleapis.com/auth/gmail.modify

For calendar campaigns (the Calendar API):

https://www.googleapis.com/auth/calendar

If you plan to use both engines, grant all three in one delegation entry, separated by commas.

Field reference

ScopeRequired forWhat it does
https://www.googleapis.com/auth/gmail.sendCold emailLets Tantra send email as the mailbox
https://www.googleapis.com/auth/gmail.modifyCold emailLets Tantra read message bodies to detect genuine replies and separate them from auto-responders
https://www.googleapis.com/auth/calendarCalendar campaignsLets Tantra create calendar events and add attendees so Google sends the invitation

The gmail.modify scope is used to tell a real reply from an out-of-office bounce. If your policy narrows Gmail access to metadata only, Tantra still works, but it cannot read message bodies, so some reply details are left blank. You do not need to grant anything broader than the three scopes above.

Step-by-step

  1. Sign in to the Google Admin console at admin.google.com as a super administrator.
  2. Go to Security, then Access and data control, then API controls.
  3. Under Domain-wide delegation, click Manage domain-wide delegation.
  4. Click Add new.
  5. In Client ID, paste your service account's client ID.
  6. In OAuth scopes, paste the scopes you need from the list above, separated by commas.
  7. Click Authorize. The new entry appears in the delegation list.

What happens next

Delegation can take a few minutes to propagate across Google's systems. After you authorize, upload the service account to Tantra if you have not already, then verify your senders. If verification fails immediately, wait a few minutes and try again.

Common mistakes

  • Pasting the service account email into the Client ID field. Use the numeric client ID, not the email.
  • Granting a broader Gmail scope such as full mailbox access. Tantra only needs gmail.send and gmail.modify.
  • Forgetting the Calendar scope when you plan to run calendar campaigns. Gmail scopes alone do not enable calendar sending.

Troubleshooting

SymptomCauseFix
Senders stay disconnected after verifyingDelegation not propagated yet, or wrong client IDWait a few minutes, confirm the client ID matches the service account, then re-verify
Sender is calendar-only, not Gmail capableGmail scopes were not included in the delegationAdd gmail.send and gmail.modify and re-verify

FAQ

Do I have to grant all three scopes?

No. Grant only the scopes for the engines you use. Cold email needs the two Gmail scopes. Calendar campaigns need the Calendar scope.

Why does Tantra need gmail.modify and not just gmail.send?

Sending needs gmail.send. Detecting real replies, and telling them apart from auto-responders, needs to read message bodies, which requires gmail.modify.

Is it safe to grant domain-wide delegation?

You grant it in your own console and can revoke it any time. The scopes above are limited to sending and reply detection. Tantra cannot use permissions you did not grant.

How long until delegation takes effect?

Usually a few minutes. If verification fails right after you authorize, wait and retry.

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