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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 or iOS 11.
Underpass for Mac requires Mac OS X 10.11 El Capitan, macOS 10.12 Sierra, or macOS 10.13 High 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.