Peer-to-peer (P2P) file transfer and chat, with end-to-end encryption 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.

Underpass can communicate between your own Apple devices or with another Underpass user. You can communicate securely over the internet or on a LAN, such as in an office, school, coffee shop, or home. Underpass even works on ad hoc peer-to-peer wifi networks. 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 communicate with a Mac, iPhone, iPad, or iPod touch using Underpass.

Underpass is made by indie developer Jeff Johnson. If you need support, please email me at or read the support site at

What’s New

Version 2.0.0

Underpass is now a Universal Binary ready for Apple silicon and macOS Big Sur.

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

App Privacy

The developer, Jeff Johnson, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Collected

The developer does not collect any data from this app.

Privacy practices may vary, for example, based on the features you use or your age. Learn More


  • Family Sharing

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

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