Server-side signatures allow Xink to apply email signatures to messages sent from non-Outlook email clients such as mobile mail apps, CRM systems, and third-party email tools.
The server-side method intercepts outgoing emails within the Microsoft 365 mail flow, applies the user’s signature configured in the Xink portal, and then returns the message to Microsoft 365 for delivery.
Since 2022, Microsoft Outlook devices can be updated using the Xink Outlook Add-in, which applies signatures directly in Outlook without rerouting emails.
Learn more about the Outlook add-in → How to update email signatures in Outlook (Outlook Add-in)
What is Server-Side?
When server-side signatures are enabled, outgoing emails are routed through the Xink ReRouter hosted in Microsoft Azure (in the same regions as Microsoft 365).
The ReRouter performs the following actions:
- Intercepts outgoing emails in the Microsoft 365 mail flow.
- Analyzes the email for existing signature patterns.
- Replaces the detected signature or text marker with the user’s Xink signature.
- Returns the processed message to Microsoft 365 for delivery.
Xink does not deliver the email to recipients. Microsoft 365 remains responsible for sending the message after the signature has been applied.
This ensures consistent branding across emails sent from any device, application, or email client.
When to Use Server-Side Signatures
Server-side signatures are typically used in the following situations:
- Emails are sent from non-Outlook clients such as Apple Mail (iOS), Android Mail, or CRM platforms.
- You want to prevent users from editing their signatures.
- Signatures do not need to be visible while composing the email.
- You want to replace default mobile signatures such as "Sent from my iPhone" or "Sent from Android".
All Xink mail servers are hosted in Microsoft Azure data centers across multiple regions including the United States, Canada, United Kingdom, European Union, and Australia.
Communication between Microsoft 365 and Xink servers is secured using TLS 1.2 encryption.
After processing the email, the message is returned to your Microsoft 365 tenant for final delivery.
Processing Delay
Because emails are routed through the Xink ReRouter, a small delay may occur.
Typical processing time is approximately 5 seconds.
Signatures are cached by the ReRouter for approximately 20 minutes. If a signature or user field value is updated, it may take a short period before the changes appear in outgoing emails.
Configure Server-Side Using the Web Console
The Xink web console acts as a secure interface between your administrator account and Microsoft 365 PowerShell. It creates a remote session and performs the required configuration automatically.
Start the Integration
- Open Preferences in the Xink portal.
- Select the Integration tab.
- Click Microsoft 365 (Server-Side).
- Select Start Integration.
Authenticate with Microsoft 365
After starting the integration:
- A window will display a device login code.
- Copy the code.
- Follow the Microsoft authentication link.
- Sign in using a Microsoft 365 administrator account.
Note: Exchange Administrator permissions (or higher) are required.
Important Authentication Note
During sign-in, you may see a message indicating that authentication has completed.
Do not close the window at this stage. The session is still finalizing the authentication process.
Create the Mail Flow Configuration
Once authentication completes, the Xink rerouting web console appears.
- Click Create.
- The system will automatically create the required:
- Transport rule
- Outbound connectors
Confirm the Configuration
If your domain appears in the list, the integration was successful.
Click Save.
By default, the transport rule is created but disabled.
You must enable it in the Exchange Admin Center.
Once enabled, it may take approximately 15–20 minutes for the configuration to propagate.
Ensure that the connectors are also enabled.
Server-Side Only Configuration
You can configure Xink to apply signatures entirely on the server.
This means all outbound emails will receive their signature during the mail flow process.
Learn more → Server-side only signature configuration
We recommend consulting Xink support before enabling this option to ensure it aligns with your environment and best practices.
Test the Server-Side Signature
Once the domain appears in the configuration list, server-side routing is active.
You can safely test the configuration without affecting users by using the marker:
{EMAILSIGNATURE}This marker allows you to confirm that the signature is correctly inserted.
To test:
- Disable all four default selections.
- Add the marker {EMAILSIGNATURE} in the test message.
- Send a test email.
Testing on Mobile Devices
Next Steps
Microsoft 365 FAQ → Microsoft 365 FAQ
Best practices → Server-Side Best Practices
