The signaling server introduces devices and exchanges WebRTC connection information. File contents are never uploaded to that server. Transfers use encrypted WebRTC data channels. If a TURN relay is configured, it forwards encrypted traffic; this is a relay, not file storage.
The service and its hosting providers can see connection metadata, including IP addresses, browser/device information, pairing and room identifiers, and connection times. STUN and TURN providers also see connection metadata. This app has no analytics or account requirement. Hosting-provider logging and retention must be confirmed by the operator before production launch.
Automatic discovery groups devices by the public IP seen by the server, rather than scanning your Wi-Fi. Shared office networks or carrier NAT may show strangers. VPNs, IPv6 and iCloud Private Relay may hide your other device. Use pairing codes or a temporary room when discovery fails. Confirm the recipient name and compare the connection code on both screens. Receiver acceptance is always required. Rooms and discovery are not identity verification.
Files of 64 MB and larger are written into temporary browser storage while receiving. Reception needs a modern browser with Origin Private File System writable-file support and enough storage quota. A 1.87 GB file needs at least that much browser storage plus space for the saved copy. Private browsing, older Safari versions and low storage can prevent reception. Use a current desktop Chrome or Edge browser for your first large-file test.
Keep both pages open and both devices awake. Backgrounding a browser, locking a phone or changing networks can interrupt transfers. Interrupted transfers restart from the beginning. Received files remain in local browser storage until this page closes; cleanup on close is best effort, and a crash can leave temporary files behind. Save received files before closing the page. Multiple-file ZIP downloads can require extra space and memory; send very large files individually.
Close all active transfer tabs before clearing. This removes only EngineerHow temporary files stored on this device and origin; downloaded files are unaffected.
EngineerHow Share is a modified version of PairDrop by schlagmichdoch, based on Snapdrop by Robin Linus. Distributed under GPLv3 with third-party notices retained. Modified source · License. No affiliation with the upstream project is implied.