Right-click any file in Windows Explorer, click "Send to ? Mail recipient", and the email appears ready to send in Gmail - no configuration needed, no subscription fees, completely open source.
Windows has a built-in email feature called MAPI (Messaging Application Programming Interface) that lets any program send emails through your default email client. This powers:
• "Send to ? Mail recipient" in Windows Explorer
• "Email" buttons in PDF readers, Office apps, and thousands of Windows programs
• Print-to-PDF-and-email workflows
• Document sharing from any application
Gmail and Google Workspace have never supported MAPI. If Gmail is your email provider, these features simply don't work.
go-mapi is the free and open-source
WHAT MAKES GO-MAPI DIFFERENT
? Free & Open Source - No subscription fees, no paid tiers, no feature locks
? Privacy-First - Data stays on your computer until you send; no third-party servers
? Simple Setup - Install extension + run one PowerShell command; works immediately
? Enterprise-Ready - Deployable via Group Policy and Chrome Enterprise Policy
? Active Development - Open source on GitHub with regular updates
KEY FEATURES
• Windows Integration: Makes Gmail your default MAPI email client
• Right-Click Sending: "Send to ? Mail recipient" from Windows Explorer
• Application Support: Works with any Windows app that uses MAPI
• Attachment Support: Send files of any size (up to Gmail's limits)
• Draft or Send: Save emails as Gmail drafts to edit later, or send immediately
• UTF-8 Support: Handles international characters correctly
• Notifications: Desktop alerts when new emails are ready
• Chrome & Edge: Works in both browsers
HOW IT WORKS
go-mapi uses a three-part architecture designed for security and simplicity:
- MAPI Interceptor (DLL) - Captures email requests from Windows applications
- Native Messaging Host (Local Service) - Watches for new emails and sends them to the browser
- Browser Extension (This Extension) - Displays emails and uses Gmail API to send
All data stays on your local machine until you explicitly send the email. No third-party servers, no data collection.