App Recommendation: Local Send

by KG5WHQ
LocalSend in the Field: Fast, Offline File Sharing for Ham Radio, CERT, and RACES Responders

LocalSend is a free, open-source, cross-platform file- and message-sharing tool that solves this problem cleanly. It works entirely on a local network (or a phone hotspot with no internet), requires no accounts or cloud services, uses HTTPS encryption, and supports Windows, macOS, Linux, Android, and iOS. From a ham radio operator, CERT, or RACES perspective, it is one of the most practical “go-kit” software tools available today.

How It Fits Emergency Communications

• Completely offline: Transfers stay on the local Wi-Fi or hotspot network. Nothing leaves the LAN, and no internet connection is required.
• No accounts or servers: Zero configuration beyond installing the app and joining the same network. This is ideal when time is short and systems are stressed.
• Cross-platform: Teams rarely have identical devices. An iPhone can send a damage assessment photo to a Windows laptop; an Android phone can push a PDF ICS-213 to a Mac; a Linux machine can share a folder of maps with tablets.
• Encrypted: Transfers use HTTPS with certificates generated on each device. Optional PIN protection adds a simple confirmation layer when needed.
• Fast and unlimited by design: It uses the full speed of the local network with no artificial bandwidth caps, making it suitable for larger files such as high-resolution photos or folders of documents.
• Open source and free: No ads, no tracking, Apache 2.0 license. Source is available on GitHub for those who want to inspect it.

These traits align directly with the needs of emergency response: simplicity under stress, independence from external infrastructure, and interoperability across whatever hardware volunteers bring.

Getting Started on Every Platform
Download only from official sources: localsend.org or the project’s GitHub releases. Prefer app stores or package managers when possible, as the app does not auto-update on every platform.

• Android: Google Play Store, F-Droid, or direct APK. Works well with Quick Settings tiles in recent versions for rapid launch.
• iOS / iPadOS: App Store. Requires a relatively recent iOS version (check current requirements).
• Windows: Official installer (EXE), portable ZIP, Winget, Scoop, or Chocolatey. Portable mode is especially useful for USB go-kits—settings travel with the app.
• macOS: App Store or DMG/Homebrew. Note firewall prompts; the app includes a shortcut to open firewall settings if discovery fails.
• Linux: Flathub, Snap, AppImage, DEB, AUR, Nix, etc. Excellent for field laptops running Linux-based radio software.

Install LocalSend on every device that might be used in an activation before the event. Test it during training or drills so the interface is familiar.Basic

Workflow in an Incident

1. Create or join a local network. This can be a regular Wi-Fi router (even with no internet uplink), a travel router, or a phone/tablet hotspot. One device can create the hotspot; others join it. No data plan usage is required.
2. Open LocalSend on the sending and receiving devices. Devices on the same network usually appear automatically under “Nearby devices.”
3. On the sender, choose Send → select files, a folder, media, or text/clipboard content → tap the target device.
4. On the receiver, accept the transfer (or configure auto-accept for trusted/favorite devices). Files default to the Downloads folder; change this in Settings for a dedicated incident folder.
5. Confirm receipt and move on.

You can also send short text messages or paste clipboard content—handy for quick coordinates, frequencies, or status notes.

Getting the Most Out of It in Emergency Operations
Pre-event preparation

• Install on all personal and team devices and test transfers between every platform combination you might encounter.
• Create a standard naming convention for devices (e.g., “EOC-Laptop-Win,” “Team3-Android,” callsign-based names) so operators can identify targets quickly under stress.
• Configure a consistent save location (e.g., a folder named “Incident-YYYYMMDD”) on each device.
• Enable optional PIN if your team wants an extra verification step.
• Favorite frequently used devices for faster selection and automatic acceptance if desired.
• Carry a portable Windows or Linux version on a USB stick as a backup.
• Practice creating a phone hotspot and connecting multiple devices to it.

During response

• Use a dedicated travel router or one phone as a controlled hotspot for the team so discovery is reliable and isolated from public networks.
• Keep LocalSend open (or easily accessible via Quick Settings on Android) while moving around the site.
• Prefer folders over individual files when sharing sets of ICS forms, maps, or photo batches.
• For very large transfers, ensure devices stay awake and connected; recent versions improved background transfer behavior on Android.
• Combine with radio operations: photograph a whiteboard status board or handwritten log, send it via LocalSend to the laptop operator who will digitize or forward via Winlink/packet, then delete sensitive local copies as needed per your data-handling procedures.
• Text/clipboard sharing is excellent for short, time-sensitive items that do not need a full document.

Platform-specific tips

• iOS: LocalSend works reliably once both devices are on the same network. Background restrictions can sometimes require the app to stay in the foreground during long transfers—test this.
• Android: Background transfers and the Quick Settings tile make it smoother for phone-to-anything workflows.
• Windows / Mac / Linux: Firewall rules sometimes block discovery (port 53317 is commonly involved). Allow LocalSend through the firewall on first run. Portable Windows builds are ideal for shared EOC machines.
• Mixed environments: Discovery relies on the local network (multicast). Guest networks, some hotel/public Wi-Fi, or aggressive isolation features can block it. A private hotspot or travel router avoids most of these issues.
• Web option: There is a web version (web.localsend.org) that can work in browsers on the same network, useful if a device cannot install the native app.

Reliability practices for the field

• Test discovery and transfer immediately after setting up the network.
• If devices do not appear, confirm they are on the same SSID/subnet, disable VPNs, check firewalls, and try manual IP entry if available in troubleshooting options.
• Battery and heat matter: keep devices powered or have power banks ready during sustained operations.
• Have a fallback (USB cable, SD card, or verbal relay) ready, but LocalSend dramatically reduces the need for them.
• Document your team’s LocalSend procedures in the go-kit checklist and communications plan.

Limitations to Keep in Mind
LocalSend requires a shared local network path—it is not a long-range or internet-based tool. It will not replace packet radio, Winlink, or voice nets for beyond-line-of-sight needs. Multicast discovery can fail on restrictive networks, which is why controlled hotspots or travel routers are recommended in the field. Always verify file integrity for critical documents (recent versions include checksum support).

Closing Thoughts
In emergency communications we train to work with what is available and to keep information flowing when infrastructure fails. LocalSend gives mixed-device teams a simple, private, high-speed way to move files and short messages without relying on the cloud or cellular data. Install it now, practice it in drills, add it to your go-kit software list, and it will be ready when the power is out and the only network you have is the one you create yourselves.

Download it from the official site, test it across your team’s phones and laptops, and incorporate it into the next training exercise. When seconds count and the internet does not, having a reliable local transfer tool can make a meaningful difference.