End-to-end encrypted file transfer and chat for complete privacy and security.

Underpass is different from every other encrypted communication app because it does not use a third-party service. It's just two devices and a password. Peer-to-peer. There's no signup. No account. No phone number, email, contacts, or any personal information requested, not even your real name.

You can communicate securely over the internet or on a LAN, such as in an office, school, coffee shop, or home. All of your data is encrypted before it's sent over the network, and it can't be decrypted except by the other device using Underpass. Industry-standard AES-128 encryption algorithm.

* File transfers of any file type
* Inline images, including animated gifs
* Unicode text and emoji chat

Underpass for iOS is also available in the iOS App Store. You can chat with a Mac, iPhone, iPad, or iPod touch using Underpass.

What’s New

Version 1.1.2

• Added a number of submenus and items under Edit in the main menu.
• Respect the System Preferences for Keyboard, Text while typing. This allows text substitutions, for example.
• Disable data detectors by default in the messages view. You can enable them manually.

Ratings and Reviews

4.6 out of 5
9 Ratings

9 Ratings

nglevin ,

Social you can trust

How can you say possibly no to a chat app with file sharing capabilities made by one dude in Wisconsin without VC buckazoids or subscriptions on The Cloud?

Best Mac app I've used in a long time. Thank you Jeff, for fighting for the users.

RastaSolo ,

Very cool app.

Love the new chat feature.

Jomewa ,

Not at all user friendly

I cannot recommend as this app is far too pedantic and quirky for a non-professional IT user


Jeff Johnson
2.6 MB

macOS 10.12 or later, 64-bit processor



Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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