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What is Underpass?
Underpass is a chat and file transfer app that features end-to-end encryption for complete privacy and security.
Communicate with another person or between your own devices.

Why Underpass?
Read the story of why I wrote Underpass and why you should use it.

What are the system requirements?
Underpass for iPhone, iPad, and iPod requires iOS 10.
Underpass for Mac requires Mac OS X 10.11 El Capitan or macOS 10.12 Sierra.

How do I get support?
For documentation and contact information, see Underpass Support.

Underpass Features:



Who is the developer?
Underpass was created by Jeff Johnson, an independent developer with over a decade of software engineering experience on Apple platforms. Jeff was a longtime engineer at Rogue Amoeba Software, working on apps such as Airfoil. Before that he was the lead engineer of Knox (originally developed by MK&C, later sold to AgileBits). Jeff was also previously the lead engineer for the open source RSS reader Vienna.