# CairnOS — Off-Grid LoRa Mesh Messaging > Off-Grid LoRa Mesh Messaging (iPhone/iPad app by Christopher Van Hoose.) - Source: https://appshunter.io/ios/app/cairnos/id6819076554 (this page in markdown: same URL + `.md`) - Developer: [Christopher Van Hoose](https://appshunter.io/developer/1510007987) - Category: Utilities, Navigation - Price: Free - Rating: 5.00/5 from 1 App Store ratings - Age rating: 4+ - Requires: iOS 18.0 · 54 MB - Languages: American English, Dutch, French (France), German (Germany), Italian, Korean, Polish, European Portuguese, Russian, Chinese (Simplified, China) and 2 more - Released: 2026-10-21 - Data updated: 2026-10-29 ## What is CairnOS? Cairn is a companion app for MeshCore LoRa mesh radios. Pair your radio over Bluetooth or WiFi and send messages through a community-built network of radios and repeaters, with no cell service, no internet and no account. MESSAGING - Direct messages, channels and room servers in one inbox, with filters - Public, private and hashtag channels; share or join a channel by QR code - Delivery status, with retry for failed sends - Emoji reactions, @mentions, forwarding, search and text selection - Path details for each message: every hop on a list and a map - On-device translation of incoming messages - Chats kept on a Cairn touch radio come over to the app when you pair - Block contacts or channel senders, filter keywords and mute conversations - Optional link previews, with a warning for known malware links DASHBOARD - Battery, network, radio, GPS, contacts and chats at a glance - Sunrise and sunset for your position and the radio's temperature sensor - Radio presets by region, or set frequency, bandwidth, spreading factor, coding rate and TX power yourself NODES & REPEATERS - Saved and heard nodes, with search, sort, filters and a card or list layout - A page for every node, with a map, readings and quick actions - Log in to your repeaters and room servers to see status, telemetry, neighbors and an SNR map, then change settings, access lists and regions or use the remote CLI - Send commands to your own companion radios over the mesh (MeshCore 1.18 firmware) - Telemetry history charts kept on your phone - Contact groups, QR sharing and a manual path editor SPECTRUM - Live noise floor and packet traffic on your frequency - Signal margin, airtime share and packets per minute - With a Cairn radio: the radio's own Channel view, with its trace, density heat map and 24-hour noise floor MAPS & GPS - Mesh map with standard, satellite and topographic layers - Live traffic layer: the links packets crossed lately, and each new packet as it arrives - Download map regions for offline use - Radio and phone GPS side by side, with a compass and a navigation HUD that points the way to any node TOOLS - Network Health, Scan for Nodes, Trace Path, Line of Sight with terrain and Fresnel zone, RX Log and a CLI terminal - Sign and verify messages with your radio's identity IN THE CAR & AROUND iOS - CarPlay: a dashboard of your radio, mesh, messages and location, a GPS page, and messages you hear and answer with Siri - Siri and Shortcuts: check radio status, send a message or send an advert - Live Activity and Dynamic Island with connection, battery and unread count - Multiple windows on iPad MAKE IT YOURS - Choose a color, gradient or photo background with glass cards over it - Give any node a photo or a color: its type's color, one of twelve shades or any color you pick - Backup and restore, plus CSV and GPX export PRIVACY Your messages travel radio to radio. Cairn has no accounts, no analytics and no developer server. Nothing is sent to the developer. REQUIREMENTS Requires a LoRa radio running MeshCore companion firmware, connected over Bluetooth or WiFi. Maps, link previews and Line of Sight elevation use the internet when it is available. Requires iOS 18 or later. Cairn is free and open source software under the GNU GPL v3, built on the work of the open-source MeshCore app community. Source code is linked from our support page. ## Is CairnOS safe? Not enough ratings yet to assess CairnOS. ## Is CairnOS legit? CairnOS appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for CairnOS is 65 out of 100 points across 7 verification signals from App Store and developer data. ## Version history (last 3 releases) ### 1.2 — 2026-10-28 Version 1.2 is about speed: connecting and syncing take less time, and big node lists stay quick. NEW - Remove Heard Nodes: Settings › Nodes › Remove Nodes clears the whole Heard list in one step. It says how many first and asks you to confirm. Saved nodes stay, and a node comes back if your radio hears it again. IMPROVED - Faster connect with a full node list: Cairn fetches only what changed, and downloads the whole list only when the radio's count and the app's differ. That also catches nodes removed on the radio while the app was away. - Faster Bluetooth on Cairn firmware for ESP32 radios. - Stock firmware: quicker connects, with no Cairn-only requests each time and no 5-second wait on older firmware. - Removing many nodes on the radio updates the app in one go instead of row by row. - The Traffic map pins only your saved and heard nodes, not every node heard in the last 7 days. Packets through relays you don't have still animate, and those relays are listed as off the map. Show Quiet Nodes and the Map tab's traffic layer follow the same rule. FIXED - A deleted node leaves the Traffic map, Line of Sight and Trace Path at once, including Trace Path's node picker. FIRMWARE Everything in 1.2 works with stock MeshCore and with current Cairn firmware. ### 1.1 — 2026-10-26 NEW - Settings, redesigned: the gear on the Dashboard opens one Settings page with your radio at the top, and Search Settings finds any setting by name. Each tab's sliders and the Dashboard's cards open the matching page over the tab you're on. - Scan for Nodes, rebuilt for busy meshes: each scan starts a fresh list of the nodes your radio hears directly, with badges like Hears you and Check Link for repeaters. A countdown shows when you can scan again. CarPlay shows the same list. - Wardrive keeps running in the background until you stop it or the radio disconnects, and each node's line starts where it was heard. - Favorites: a foldable group at the top of Nodes and Comm. - Receive switches: Settings › Radio › Receive has Front-End LNA and Boosted RX Gain on radios that have them. - Background help: Background App Refresh checks in on a WiFi radio, and "Cairn May Not Be Receiving" asks you to open the app after 45 quiet minutes. Turning Bluetooth off posts "Bluetooth Is Off". - RX Log counts packets the radio heard that never reached the app. - Dashboard: the Nodes card counts nodes heard in the last 10 minutes, and Trace Path has its own tile. IMPROVED - Relays are named only when your radio actually heard them. - Traffic map: your own messages show as pulses, and each packet draws its line as it crosses the map. - Tap the Cairn logo at the top left for Device Info. - On Heltec boards with an amplifier, TX power shows the power at the antenna. - Deleting a node forgets it everywhere, and Remove Nodes acts at once. - The Live Activity uses less battery. It reads "Live" or "Quiet · 12 min". - With the phone as position source, the radio's pin follows you. FIXED - Messages keep arriving in the background, and a late receipt turns Failed into Delivered. - Picking a preset writes it to the radio, and onboarding no longer sticks on "Pick a preset". - Adding a region works, and repeaters with many regions load. - Dashboard cards no longer freeze on a busy mesh. - Stock firmware: fewer missed messages and missed Delivered ticks. - Restoring a backup re-reads your channels on the next connect. FIRMWARE Receive switches need MeshCore 1.18 or later. Scans need 1.10 or later, and noise and loss counts 1.11 or later. ### 1.0 — 2026-10-21 No release notes. ## More apps by Christopher Van Hoose - [GenR8](https://appshunter.io/ios/app/genr8/id6751822886) - [ResEditor](https://appshunter.io/ios/app/reseditor/id6752496598) - [Switcher Pro](https://appshunter.io/ios/app/switcher-pro/id6754262874) All apps by Christopher Van Hoose: https://appshunter.io/developer/1510007987 ## Related topics [lora](https://appshunter.io/ios/topics/lora) --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-29.*