AlterSend

About

AlterSend is an open-source app for sending files, text, and folders end-to-end encrypted, either directly to your own devices or to anyone with a link. Files move device-to-device rather than being uploaded to cloud storage, so they only exist on the two devices involved, and there are no accounts or size limits for direct transfers. Once you pair your devices with a QR code or short code, they recognize each other automatically; recipients without the app can download via a browser link.

If a direct connection isn't possible, an encrypted relay forwards the data without being able to read it. Relay-routed transfers are capped at 20 GB between apps and 10 GB for browser links, while direct transfers are unlimited and you can run your own relay. Interrupted transfers resume where they left off. AlterSend is Apache-2.0 licensed and available for macOS, with other platforms listed on the site.