Open source

The Stow engine will be free and open source under the Apache 2.0 licence. The Mac app is the paid, polished layer on top.

Why open source

Stow asks for access to years of your email. You should be able to see exactly what it does with it. Publishing the engine lets anyone check that it only reads, that it keeps everything on your Mac, and how it encrypts your archive.

What the engine includes

• Sync: read-only IMAP download from Gmail and Microsoft accounts, signed in with OAuth.
• Encryption: the encrypted archive and its keys.
• Search: full-text search across messages and attachments.
• Rules: the visible, adjustable rules that spot bulk mail.
• MCP server: the optional local connector for AI assistants.
• The stowmail command-line tool.

Anyone can build the engine, use it from the command line, or build their own client on it.

The Mac app

The Stow app for Mac is a separate, paid product built on the engine: the window, the menu bar icon, guided setup, tidy-up and clean-up screens, signed and notarised builds, automatic updates and support. See pricing.

Licence

The engine will be released under the Apache License, Version 2.0, copyright T1G OÜ. Contributions come in under the same licence, with no separate contributor agreement.