Frequently Asked Questions

Everything you need to know about peer-to-peer file sharing with FlashPeer.

FlashPeer uses WebRTC DataChannels to establish a direct, peer-to-peer encrypted connection between two browsers. When you click Send, your files are sliced into binary chunks and sent directly to the receiver device without ever touching or storing on a remote server.

There are no artificial file size limits imposed by FlashPeer. You can share high-definition videos, large archives, disk images, or entire folder trees directly between devices without arbitrary caps.

Yes, it is possible. Because WebRTC transfers assemble file data inside the browser, if a file is extremely huge and your browser or device runs out of available RAM, the browser tab can run out of memory and crash (e.g., an "Aw, Snap!" or Out of Memory error).

Recommended browsers that don't usually crash*:
For large multi-gigabyte transfers, we recommend using Chromium-based desktop browsers:

  • Google Chrome (Desktop)
  • Microsoft Edge (Desktop)
  • Brave Browser (Desktop)
  • Opera (Desktop)

These desktop browsers support the Native File System Access API. This allows FlashPeer to stream incoming file chunks directly to your physical hard drive chunk-by-chunk instead of keeping the entire file in RAM, meaning they don't usually crash*.

*Important Note: Even browsers like Google Chrome and Microsoft Edge which can handle big files can still crash sometimes if your hard drive runs out of free space, if system memory is exhausted by heavy background apps, or on mobile devices where operating systems enforce strict per-tab memory limits.

To maximize your WebRTC direct transfer throughput:

  • Use 5 GHz Wi-Fi or Mobile Hotspot: Connect both devices to the 5 GHz band of your home/office router or turn on your phone's personal Wi-Fi Hotspot. 5 GHz Wi-Fi provides significantly lower latency and dramatically higher bandwidth than congested 2.4 GHz channels.
  • Disable Client/AP Isolation on Routers: Some guest Wi-Fi networks prevent devices on the same router from talking directly to each other. On standard home networks, devices negotiate direct local peer-to-peer routes.
  • Keep Tabs in Foreground: Browsers throttle background tabs aggressively to conserve battery. FlashPeer automatically requests a Screen Wake Lock to prevent your display from sleeping, but keep the tab visible until 100% completion.
  • Chromium Browsers for Multi-Gigabyte Files: On desktop and mobile, Chrome, Edge, and Brave support native disk streaming to bypass memory limits.

Device 1 opens FlashPeer in Send Files mode, which displays a 5-digit room code and a Share Link. Device 2 opens FlashPeer in Receive Files mode and enters the 5-digit code (or simply clicks the link). The two devices negotiate a connection in under 2 seconds.

Yes. All WebRTC transfers are end-to-end encrypted using DTLS (Datagram Transport Layer Security). The cryptographic keys are negotiated directly between the two browser clients, meaning neither FlashPeer nor your internet service provider can read your files.

FlashPeer is a Progressive Web App (PWA) installable across all modern devices:

• Chrome / Edge / Brave (Android, PC, Mac): Click the install icon in your browser's address bar or menu (⋮ / ⋯) and select Install FlashPeer.

• Safari (iPhone & iPad): Tap the Share button (square with arrow) at the bottom of Safari, scroll down, and tap Add to Home Screen.

• Firefox: On mobile, tap the menu (⋮) and choose Install or Add to Home Screen.

Because FlashPeer streams directly peer-to-peer in real time, closing the tab, locking the phone screen, or switching Wi-Fi networks will disrupt the connection. Keep both browser tabs active until the transfer reaches 100%.

Yes! Click the Add folders button or drag and drop an entire folder hierarchy. FlashPeer preserves directory paths and file hierarchy for the recipient.