Login with email magic links

Magic links can be sent to users by email in order to authenticate existing users.

Check out our sample app

How it works

Here's an example of a magic link integration. Transmit APIs are shown in pink along with the relevant integration step.

Before you start

Before you start your integration, you'll need a Transmit application. See create an application

Step 1: Sign up users

Before you can login users into your app, they will need to be created in your Transmit tenant and associated with your app. New users can be created using a POST /users request, which must include the user's email address. If the user already exists in your Transmit tenant but isn't yet associated with your app, this request will just add the user to your app (but won't update any other details).

Step 2: Create redirect URI

Create the client-side redirect endpoint that will receive a code when the user clicks the magic link in their email. The redirect URI should accept code as a query parameter. For example, if https://domain.com/verify is your redirect URI, then Transmit will redirect to https://domain.com/verify?code=123abc when the user clicks the link. Your endpoint should pass the code it receives to your backend, where it will be used to obtain user tokens, as described in Step 5.

Step 3: Add redirect URI to app

Add the redirect URI (e.g., https://domain.com/verify) as an allowed redirect URI for your Transmit application. This will also be the redirect_uri that you'll need to pass in the send request. From the Admin Portal under Applications, click on your application to edit its settings and add this URI under Redirect URIs.

Step 4: Send magic links

Use a send request like the one below to send a magic link to the specified email address. The redirect_uri should correspond to the redirect endpoint you created in step 2 and added as a redirect URI in step 3. To customize the email, see Next steps. If the request succeeds, a 200 response is returned.

import fetch from 'node-fetch';

async function run() {
  const resp = await fetch(
    `https://api.transmitsecurity.io/cis/v1/auth/link/email/send`,
    {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        Authorization: 'Bearer [ACCESS_TOKEN]' // Client access token
      },
      body: JSON.stringify({
        email: '[EMAIL]', // User's email address
        redirect_uri: '[REDIRECT_URI]' // URI that receives a code when the link is clicked
      })
    }
  );

  const data = await resp.json();
  console.log(data);
}

run();

Step 5: Authenticate magic links

When the magic link is clicked, your redirect URI receives a code which your client will then pass to your backend so it can be used to obtain user tokens. Create your backend endpoint that will receive this code and then send a magic link auth request like the one below. If successful, a 200 response will be returned with the user tokens, which should be validated as described here.

import fetch from 'node-fetch';

async function run() {
  const resp = await fetch(
    `https://api.transmitsecurity.io/cis/v1/auth/link/email/authenticate`,
    {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        Authorization: 'Bearer [ACCESS_TOKEN]' // Client access token
      },
      body: JSON.stringify({
        code: '[CODE]' // Code returned to your client-side redirect endpoint
      })
    }
  );

  const data = await resp.json();
  console.log(data);
}

run();

Here's an example of a successful response:

{
  "access_token": "string",
  "id_token": "string",
  "refresh_token": "string",
  "token_type": "string",
  "expires_in": 3600,
  "session_id": "string"
}

Next steps

Once you've completed a basic integration, here are some customizations you can consider:

• Email customization
• Link settings
• Custom email provider
• Security considerations

Email customization

The default email template for Login can be customized either from the Admin Portal or via API (but not both). From the Admin Portal (Authentication > Email magic links), you can customize the color of the button and email address that appear in the message. The email message will use the application's logo and name (see screenshots below for default texts). The subject, text and appearance can also be customized using the email_content object in the send request.

Here is a screenshot of the email templates with their customizable field names:

Link settings

From the Admin Portal (Authentication > Email magic links), you can customize settings for the selected app:

• Expiry time in minutes for the link sent in the email
• Email sender name ("from" name)

If needed, this expiration time can be overwritten for a specific request using the expiration_time parameter.

Custom email provider

In the Admin Portal (from Settings > Email Provider), you can configure to use your custom email provider (e.g., SMTP or SendGrid) instead of the Transmit default.

Security considerations

To secure your magic link implementation, here are some recommendations.