Mirall

What it is

Mirall is a secure file transfer application designed for very large files. It enables direct device-to-device transfer of data—from hundreds of gigabytes to terabytes—without involving cloud storage or requiring user accounts. Files remain encrypted end-to-end and are served from their original locations rather than being uploaded to servers.

The application works through shared spaces where users can invite team members or collaborators. Once invited, participants can browse and download files directly from the devices that shared them. Mirall operates offline-first and can work through most home and office networks without requiring port configuration. For restricted networks, users can enable relay connections that forward encrypted traffic.

All connections are end-to-end encrypted by default, with no key management required. Mirall stores no files on servers, charges no per-gigabyte fees, and imposes no size limits on transfers. The application is available for macOS, Windows, and Linux.

Questions from the bench

Where are my files stored?

Files are stored only on your device where they already are. When sharing a file, it remains on your disk while other members download it directly from you. No server stores your files, and once someone downloads a file, they have their own local copy on their device.

Do both of us need to be online at the same time?

Yes, files move directly between devices, so the person sharing a file must be online and running Mirall while you download it. However, you do not need to watch the transfer; if either person goes offline, the transfer pauses and resumes where it left off when you are both back online.

Will Mirall work on my network?

Mirall almost always works without setup by finding its own way through home and office routers without requiring port forwarding. However, some strict corporate firewalls, mobile routers, and VPNs may block the traffic needed. Mirall will notify you of what's in the way and suggest what to try. For blocked networks, Mirall can route connections through a relay that forwards encrypted traffic it cannot read.

What happens when I'm offline?

Files you have already downloaded stay on your device and work offline. Other members can still see what you have shared, but they cannot download it from you until you return online. Downloaded files do not make you a second source; the original sharer serves the files.

Is it really encrypted?

Yes, every connection between devices is end-to-end encrypted with no keys to manage. On your device, Mirall encrypts its own records of which spaces you are in, who is in them, and what you share, and keeps your identity key in the system keychain.