Is there a way to invite attendees outside the organization? - google-calendar-api

Question

I have read the google calendar API docs but I couldn't find a way of inviting guest outside the account's organization, is this possible?
This is my code with the NodeJS client:
const auth = new google.auth.GoogleAuth({
keyFile: 'src/google-api/calendar-auth.json',
scopes: ['https://www.googleapis.com/auth/calendar'],
});
const calendar = google.calendar({ version: 'v3', auth });
calendar.events.insert({
calendarId: 'email-of-organization',
sendUpdates: 'all',
requestBody: {
start: {
dateTime: startDate.toISOString(),
timeZone: 'utc',
},
end: {
dateTime: endDate.toISOString(),
timeZone: 'utc',
},
summary: 'a summary',
description: 'a description',
attendees: [{ email: 'email#outside.org' }], // this email is outside my organization
},
});
The error:
Service accounts cannot invite attendees without Domain-Wide Delegation of Authority
Even if I setup Domain-Wide Delegation, the error persists.

Answer 1

Basically you authorizing your service account to access data on behalf of users in your domain when you delegate domain-wide authority to your service account. See Delegating domain-wide authority to the service account
Once you finished delegating domain-wide authority, your application now has the authority to make API calls as users in your domain (to "impersonate" users). When you prepare to make authorized API calls, you specify the user to impersonate.
It is possible to invite guests outside your domain (using your user account or a service account). You have the option to warn the users when inviting guests outside your domain. See Allow external invitations in Google Calendar events
I tried creating an event using my user account and add a guest from outside the domain with events.insert. It was successfully created. Therefore, if you let your service account to impersonate a user in your domain it should be able to create events and invite guests outside your domain as well