Thunderbird:Microsoft Graph API

Microsoft Graph API Support in Thunderbird

Warning: Graph support in Thunderbird is new. Some remaining bugs may exist, if you encounter any please open a bug.

Graph API is the the Microsoft 365 protocol for accessing user, email, calendar and other data. Thunderbird's Graph implementation is currently limited to email only. Please also note that Graph is available only on Microsoft 365. On-premises Exchange accounts should continue to use Thunderbird's IMAP or Exchange Web Services support.

Many organizations on Microsoft 365 use custom domains, so even if your have an address affiliated with your organization, if they are using Microsoft 365, then the Graph protocol should be supported. Microsoft will be turning off support in Microsoft 365 for EWS in late 2026, so to continue to use Thunderbird with Microsoft 365 accounts for which IMAP is unavailable, users will need to use the Graph protocol.

Account Setup

Graph accounts can be set up using Thunderbird's AccountHub. To start setup, select Add New... > Email Account from the main menu and enter the email address associated with your Microsoft 365-hosted organization.

Automatic Configuration

In most cases, for organizational email addresses that use Microsoft 365 hosting, the ability to use Graph API should be automatically detected from the email address. In that case, after pressing Continue in AccountHub you should be presented with alternatives for accessing your account. Choose the "Microsoft Graph API" option from the list in AccountHub, press Continue again, and the account should be set up.

Manual

If automatic configuration does not work, you can perform a manual configuration. In the AccountHub manual configuration screen. Select "Graph" for the protocol and in the "Exchange endpoint URL" field, enter https://graph.microsoft.com/ . Choose "OAuth2" for the authentication method and your email address for the username.

Custom Application/Tenant ID (uncommon)

Most users should not need this.

Thunderbird has its own application ID that is designed to work for most users. However, if your organization requires custom application or tenant IDs, then you should configure the account using the manual configuration process, and once the information is complete, press the "Advanced Configuration" link. Once in the account settings screen for the new account, choose "Server Settings" and press the "Advanced" button. Check the Override Office365 Settings box, enter your organization-provided application and tenant IDs and the following information:

• Redirect URI: https://localhost
• Endpoint Host: login.microsoftonline.com
• OAuth Scopes: https://graph.microsoft.com/User.Read https://graph.microsoft.com/MailboxFolder.ReadWrite https://graph.microsoft.com/Mail.ReadWrite https://graph.microsoft.com/Mail.Send offline_access

Supported Email Features

The Graph implementation should support all of the same operations as EWS. Thunderbird Exchange supported features. Calendar is not yet supported.

How to stay informed

Open Bug Reports

Bugs related to Exchange and Graph support are in the MailNews Core :: Exchange component in Bugzilla. Confirmed issues are currently triaged in the Exchange maintenance metabug.

Reporting Bugs

To report an issue, please file an issue in the MailNews Core :: Networking:Exchange component in Bugzilla and note the use of the Graph protocol.

Items to Test

Graph support is new, so we would appreciate testing from community members with access to Microsoft 365 accounts. Here is a non-exhaustive list of functionality we expect to work:

Account Setup and Configuration

• Configure an EWS account in Thunderbird
• Authenticate using username and password
• Use the Account Hub to register EWS accounts
• Optionally disable Account Hub in settings for legacy account setup

Email Synchronization

• Synchronize inbox and subfolders
• Automatically sync new emails

Folder Management

• Create, rename, and delete folders
• Synchronize folders and subfolders
• Move and copy emails between folders

Email Handling

• Send, receive, reply to, and forward emails
• Attach files and inline images
• Mark emails with tags
• Delete emails and confirm proper synchronization

Additional Features

• Search emails (test both subject and body)
• Use "Save as Search", Quick Filter, and sort options
• Check folder properties (e.g. retention settings)
• Confirm message sync behaviors

Filter Creation and Management

• Create filters based on sender, body, recipient, subject, size, date, etc
• Define actions such as move or copy
• Apply filters automatically on incoming mail
• Run filters manually on selected folders
• Edit, disable, delete filters and view filter logs