Microsoft Graph API transport for Nodemailer

This module is a transport plugin for Nodemailer that use Microsoft Graph API to send e-mails from a tenant.

Usage

Creation of an application on Microsoft Entra

1. Go to Microsoft Entra admin center
2. Click on App registrations then New registration
3. Give a name, leave other parameters as default (single tenant, no redirect URL)
4. Register the new app
5. Keep the Application (Client) ID and Directory (Tenant) ID

Create a secret

1. Go to Manage -> Certificates and secrets
2. New client secret, give it a name
3. Keep the client secret value

Add graph permissions

1. Go to Manage -> API permissions
2. Add a permission
3. Select Microsoft Graph then Application permissions
4. Search for Mail.Send, select it and click on Add permissions
5. Click on Grant admin consent for "your tenant"

Install this transport

Install via npm

npm install nodemailer-msgraph-transport

Require the module and intialize it with the Microsoft application credentials

const nodemailer = require('nodemailer')
const MsGraphTransport = required('nodemailer-msgraph-transport')

const msGraphConfig = {
  clientId: 'MS_GRAPH_CLIENT_ID',
  tenantId: 'MS_GRAPH_TENANT_ID',
  clientSecret: 'MS_GRAPH_TENANT_SECRET_VALUE',
  userPrincipalName: 'id | userPrincipalName'
  saveToSentItems: true
}

const msGraphTransport = new MsgraphTransport(msGraphConfig)

const transporter = nodemailer.createTransport(msGraphTransport)

userPrincipalName and saveToSentItems can be overridden for each mail in the message object passed to sendMail()

When sending a batch of e-mails, you can request a token before hand to avoid unnecessary requests to Microsoft graph api authentication server. The token will be automatically cached.

await msGraphTransport.getAccessToken()

transporter.sendMail(mailData)
transporter.sendMail(mailData)
...

Limitations

Attachements are currently not supported.

References

• SendMail graph function: https://learn.microsoft.com/en-us/graph/api/user-sendmail
• graph message: https://learn.microsoft.com/en-us/graph/api/resources/message

Licence

Licensed under the MIT Licence.