For iOS and Mac

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:

• Peer-to-Peer — There's no signup or account. Underpass does not connect to a third-party service. Your Mac or iOS device makes a direct network connection to another Mac or iOS device.
• Privacy — Underpass does not request your phone number, email, contacts, or any other personal information. You don't even need to use your real name.
• Chat over the internet or on a local area network (LAN).
• Encrypted file transfers!
• Inline images, including animated gifs.
• Full Unicode and emoji support.
• Industry-standard AES-128 encryption.

Screenshots:

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.