This Student Built a Media Server That Never Touches Your Data Plan

AirNode is a free Windows app that turns your PC into a private file explorer and media server that any phone on the same Wi-Fi or hotspot can open in a browser, with no internet connection, no cloud account and no cellular data burned. Benson Musonda, a student at Mulungushi University in Zambia, built it because moving a film or a folder of lecture recordings from laptop to phone should not cost a data bundle, and the hardest problem turned out to be something most hobby projects skip entirely: making local HTTPS trustworthy on a phone.

• AirNode serves your PC's files to any browser on the local network at airnode.local:8000, found by scanning a QR code.
• It streams video, music and photos with seekable playback, transcodes with ffmpeg, and can cast to a Chromecast.
• Benson built a local certificate authority into the app so phones connect over HTTPS without scary browser warnings.
• It ships as a single Windows executable and an installer, with seven releases since August 2026.

What does AirNode actually do?

"Airnode turns your PC into a fast, secure local file explorer and media streaming server reachable from phones and devices on any connected local network with no internet connection required," Benson told us. In practice you run AirNode.exe, pick a PIN on the first-run setup page, join your phone to the same Wi-Fi or to your phone's own hotspot, and scan the QR code AirNode shows on the PC. The phone opens a web app that browses the PC's folders, previews images, video, audio, PDFs and text, downloads single files or a batch as a ZIP, and uploads back to the PC in resumable chunks.

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It goes well past a file browser. There are separate hubs for Cinema and TV, Music, Photos and Recent or Starred files, video transcoding to H.264 and AAC through ffmpeg for phones that cannot play a format natively, auto-generated thumbnails, ID3 and EXIF metadata with cover art, watch-progress tracking in SQLite, and casting to a Chromecast on the same network. Seeking inside a long video works because the server answers HTTP 206 range requests, the same mechanism commercial streaming sites use.

Why build a media server when cloud apps exist?

"I built Airnode to stream media and share large files between my PC and mobile devices without using cellular data or third party cloud apps," Benson said. That is the whole motivation, and it is a sharper one than it sounds. Cloud sync apps route a file from the laptop up to a data centre and back down to a phone sitting half a metre away, which costs time, storage quota and, on a metered connection, real money. A hotspot between two devices in the same room has plenty of bandwidth and no meter at all, as long as something on the PC is willing to serve the files. AirNode is that something, and its FAQ states the privacy position plainly: files stream directly between devices on the local network, and the only outbound request is an optional update check against GitHub.

What was the hardest part of building it?

"The hardest part was balancing security and UX around local HTTPS," Benson said, "that is generating and enrolling local CA certificates so mobile browsers don't trigger alarming warnings across changing WiFi networks, while ensuring the app remains simple and secure for non-technical users."

This is the problem most local-server projects quietly dodge by serving plain HTTP. Browsers only trust HTTPS certificates that chain back to a known authority, and no public authority will issue a certificate for a laptop's address on a hotspot. So AirNode generates its own "AirNode Local Root CA" the first time it runs, then issues a server certificate signed by that root, listing the PC's current LAN IP addresses as subject alternative names. When the laptop joins a different network and picks up a new IP, the server certificate is checked and reissued so the addresses still match. A detail from the source shows how much testing went into it: server certificates are kept at 825 days or less, because Apple's iOS refuses anything longer from a custom root.

Benson also made a deliberate call not to install the root certificate silently. The code comments explain that an automatic attempt at startup was suppressing the confirmation dialog on most machines, so installation is now a visible action under Settings, written into the current user's trusted store through .NET's X509Store API so it needs no administrator rights. On top of the PIN, stored only as a salted SHA-256 hash, there is an optional trusted-networks mode that fingerprints a network by its Wi-Fi name or gateway MAC address and refuses to serve on networks you have not approved, which matters when the same laptop moves between a home hotspot and a campus network.

How is it built and shipped?

The stack is Python and FastAPI on the server, with a front end built from HTMX and Alpine.js so there is no build step, and every asset, including the Lucide icons and the Inter font, is bundled locally so the interface works fully offline. SQLite holds watch progress, recent files and metadata caches. The repository, created in June 2026, has around 64 commits, and the project is packaged with PyInstaller into a single-file executable plus an Inno Setup installer that installs to the user folder without admin rights.

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The finishing touches are the kind usually found in paid software: a system tray icon with quick actions, single-instance detection so a second launch opens the running copy instead of starting a rival server, automatic fallback to the next free port if 8000 is taken, autostart through Windows Task Scheduler, and an in-app update checker. The FAQ is also candid about the rough edge every unsigned indie app hits: Windows SmartScreen will warn on first launch until the publisher builds reputation or signs the build.

1. Jun 2026Repository created FastAPI server, first file browser
2. 3 Aug 2026v2.0.0 released standalone exe and installer
3. 16 Aug 2026v2.1.0 three point releases the same night
4. 15 Sep 2026v2.1.1 latest build on GitHub Releases

Our take

Plenty of student projects serve files over a LAN. What makes AirNode worth featuring is that Benson treated the unglamorous part as the product: certificates that survive a network change, an iOS validity limit most developers only learn about when a user complains, a PIN that is hashed rather than logged, and a refusal to silently modify the system trust store. It is built for a real constraint, expensive mobile data, that a lot of software written in places where data is cheap never considers. If you have a Windows laptop and a phone that keeps running out of bundle, it is a genuinely useful tool, not just a portfolio piece.

AirNode was built by Benson Musonda, a student at Mulungushi University in Zambia. Try it or read the code: GitHub · downloads · Benson on GitHub.

Reporting based on a direct interview with Benson Musonda and the public AirNode repository. GenZTech has not independently audited AirNode's security. The hero image is illustrative, not a screenshot of AirNode.