To be able to install the PWA from a self-hosted instance, the connection needs to be [established through HTTPS](https://developer.mozilla.org/en-US/docs/Web/Progressive_web_apps/Installable_PWAs).
See [this host your own section](https://github.com/schlagmichdoch/PairDrop/blob/master/docs/host-your-own.md#testing-pwa-related-features) for more information.
It uses a WebRTC peer to peer connection. WebRTC needs a Signaling Server that is only used to establish a connection. The server is not involved in the file transfer.
If your devices are paired and behind a NAT, the PairDrop TURN Server is used to route your files and messages. See the [Technical Documentation](technical-documentation.md#encryption-webrtc-stun-and-turn) to learn more about STUN, TURN and WebRTC.
If you host your own instance and want to support devices that do not support WebRTC, you can [start the PairDrop instance with an activated Websocket fallback](https://github.com/schlagmichdoch/PairDrop/blob/master/docs/host-your-own.md#websocket-fallback-for-vpn).
Files are sent directly between peers. PairDrop doesn't even use a database. If you are curious, have a look [at the Server](https://github.com/schlagmichdoch/pairdrop/blob/master/index.js).
If your devices are paired and behind a NAT, the PairDrop TURN Server is used to route your files and messages. See the [Technical Documentation](technical-documentation.md#encryption-webrtc-stun-and-turn) to learn more about STUN, TURN and WebRTC.
Yes. Your files are sent using WebRTC, which encrypts them on transit. To ensure the connection is secure and there is no MITM, compare the security number shown under the device name on both devices. The security number is different for every connection.
- [How to open a hotspot on Windows](https://support.microsoft.com/en-us/windows/use-your-windows-pc-as-a-mobile-hotspot-c89b0fad-72d5-41e8-f7ea-406ad9036b85#WindowsVersion=Windows_11)
- [How to open a hotspot on Mac](https://support.apple.com/guide/mac-help/share-internet-connection-mac-network-users-mchlp1540/mac)
- [Library to open a hotspot on Linux](https://github.com/lakinduakash/linux-wifi-hotspot)
You can also use mobile hotspots on phones to do that.
Then, all data should be sent directly between devices and your data plan should not be charged.
Snapdrop and PairDrop are a study in radical simplicity. The user interface is insanely simple. Features are chosen very carefully because complexity grows quadratically since every feature potentially interferes with each other feature. We focus very narrowly on a single use case: instant file transfer.
We are not trying to optimize for some edge-cases. We are optimizing the user flow of the average users. Don't be sad if we decline your feature request for the sake of simplicity.
