Why Transfer Files Without Internet?
Traditional cloud storage services (Google Drive, WeTransfer, Dropbox) force your data through a slow, two-step round trip: uploading across your home broadband uplink (often capped at 10–20 Mbps) to a remote corporate server, then downloading it again onto the receiving device.
Textunnel operates on a pure Local Area Network (LAN) peer-to-peer pipeline:
- Zero Broadband Bottlenecks: Transmits data directly through your local Wi-Fi router at hardware speeds (300 Mbps to 1,200 Mbps). A 5GB 4K video transfers in under 45 seconds.
- Zero Cellular Data Costs: Send hundreds of gigabytes over a mobile hotspot without consuming a single megabyte of your phone data plan.
- Absolute Air-Gapped Privacy: Data packets never exit your local network switch. Ideal for proprietary code, confidential client agreements, and sensitive healthcare records.
How to Transfer Files Offline in 3 Simple Steps
Connect to Same Wi-Fi
Ensure Device A and Device B are connected to the same Wi-Fi router or a shared mobile phone hotspot.
Open Textunnel & Pair
Open textunnel.com on both browsers. Scan the on-screen pairing QR code or enter the 6-character room ID.
Stream at Gigabit Speed
Drag and drop your files or folders. They stream directly across your local network at wire speed with automatic disk saving.
Technical Architecture: Local WebRTC & Host ICE Candidates
How does browser-based transfer function when the public internet is inaccessible?
Local Host Candidate Discovery
During peer connection establishment, WebRTC gathers host ICE candidates directly from your network interface (e.g. 192.168.x.x or 10.x.x.x), allowing direct UDP sockets to bind locally without STUN/TURN relays.
Stream Backpressure Engine
Streams 64KB ArrayBuffer binary chunks via RTCDataChannel.bufferedAmountmonitoring, maintaining negligible memory consumption (<50MB RAM) regardless of whether transferring 500MB or 50GB.
Offline File Transfer Options Compared
| Method | Internet Required | Transfer Speed | Hardware Cables / USB | Cross-Platform |
|---|---|---|---|---|
| Textunnel (Local P2P) | No (100% Offline LAN) | 30–100 MB/s (up to 110+ MB/s) | None (Wireless) | iOS, Android, Mac, Windows |
| Cloud Drives (Drive, Dropbox) | Mandatory | Slow (1-5 MB/s upload) | None | Yes |
| Bluetooth File Transfer | No | Extremely Slow (~200 KB/s) | None | Incompatible iOS ↔ PC |
| USB Flash Drive / OTG Cable | No | Fast | Requires physical adapters | Format conflicts (NTFS vs APFS) |
Frequently Asked Questions (FAQ)
Can I transfer files between devices without an internet connection?
Yes. Once the Textunnel web application is loaded into your browser (or cached via PWA), files stream directly between devices across your local Wi-Fi router or mobile phone hotspot without consuming any cellular data or needing public internet access.
How does offline local file transfer work without internet?
Devices on the same local area network (LAN) or mobile hotspot communicate directly via WebRTC DataChannels using local IP ICE candidates. Data packets travel directly from device to device at full router speed (30–100 MB/s, up to 110+ MB/s on Wi-Fi 6) without uploading to the cloud.
Can I use a phone hotspot with no cellular reception or data plan?
Yes. Turn on your smartphone's Personal Hotspot and connect your laptop or second device to it. Even if your phone has 0 bars of cellular service or mobile data turned off, a local Wi-Fi subnet is formed, allowing Textunnel to transmit files at high speeds.
Do I need to install an app on iOS or Windows to transfer offline?
No. Textunnel functions directly in standard web browsers including Safari, Chrome, Edge, and Firefox. There are no app store downloads, driver installations, or administrative permissions required.
Is there a limit on file size when transferring offline?
No. Textunnel utilizes chunked stream flow control with backpressure, allowing you to transfer 10GB, 50GB, or even larger 4K video libraries without running out of browser memory.
How fast is offline LAN file transfer compared to cloud drives?
Cloud services (Google Drive, Dropbox) are limited by your slow internet upload bandwidth (usually 10-20 Mbps). Offline Textunnel transfers utilize your local router's full physical bandwidth (300 Mbps to 1,000+ Mbps), achieving speeds of 30MB/s to 100 MB/s (up to 110+ MB/s on Wi-Fi 6).
Does offline file transfer work on airplanes or in remote outdoor areas?
Yes. As long as both devices share a local connection (such as connecting to an airplane's local Wi-Fi without buying the internet pass, or connecting to a portable travel router/hotspot), offline transfers work seamlessly.
Are my offline transfers encrypted and private?
Yes. All WebRTC traffic is automatically encrypted end-to-end with DTLS 1.2/1.3 and AES-GCM. Because data never leaves your physical local network, it is completely immune to cloud data breaches or surveillance.
Can I transfer entire folders offline without manually zipping them?
Yes. Textunnel supports client-side folder drag-and-drop. The browser packages and streams directories on-the-fly directly to the receiving device.
What happens if a device goes to sleep during an offline transfer?
Textunnel integrates the Screen Wake Lock API to automatically prevent your phone or laptop screen from locking during active transfers, ensuring long file streams complete without interruption.