How the Mailto Button Works
When you add a Button and set the Link Type to Send Email, Knak creates a clickable button.
When someone clicks the button:
Their default email client opens
A draft email appears
The draft includes the email address, subject line, and message body you configured
This makes it easy for users to contact you with pre-filled information.
Configure a Mailto Button
Step 1: Add a Button
Drag a Button element into your layout.
Click the button to open the settings panel.
Step 2: Set the Link Type
In the sidebar, locate Link Type.
Select Send Email.
Step 3: Configure Email Details
After selecting Send Email, configure the following fields:
Mail To – Enter the recipient’s email address.
Subject – Enter the email subject line.
Body – Enter the message content that should appear in the draft.
Step 4: Test the Mailto button link
Once your mailto link is set up, test it to make sure it works as expected. You can do this by opening your email in the Knak preview and clicking the button, or by sending yourself a test email and clicking the button there.
When clicked, the button should open a new draft email in your default email client with the recipient, subject line, and body content pre-filled.
Tips for Configuring Your Send Email Button
Message Length Limits (Outlook for Windows)
Microsoft Outlook for Windows has a character limit for clickable links.
We recommend keeping the combined Subject and Body under 1,250 characters. If you exceed this limit, Outlook may not open the draft email window.
Link Tracking
It is not recommended to enable tracking on Mailto buttons. Tracking can interfere with how email clients process the link. This may prevent the draft from opening.
You can disable Platform Link Tracking in the sidebar by clicking the tracking icon.
If this option is not available in your instance, contact your Customer Success Manager (CSM) or Knak Support.
For more technical details, review this external resource:
Stop Trying to Track Mailto Links If You Want Them to Work
Yahoo Mail Behavior
Yahoo Mail removes line breaks from pre-filled draft emails.
This affects:
Yahoo Mail in a web browser
Yahoo Mail app for iOS
The Yahoo Mail app for Android supports line breaks. Write your message so it remains clear even without line breaks.
Best Practices
Keep your subject line short and clear.
Keep your message simple and readable without formatting.
Avoid special characters when possible.
Test the button in multiple email clients before publishing.
Need more help? Contact support via live chat using the chat bubble in the bottom right corner or email support@knak.com.