Messaging
571 open source Messaging apps
OTG Keyboard
APK
BluetoothConnect lets you use your Android device as A Bluetooth Keyboard, supporting OTG as well.How to usepair Android and other devices, like Windows or iPhone to get the device nameforget this Android on Windows; no need for iPhoneopen this app, choose Windows or iPhone's name to connectif it's Windows, it will pop pair-dialog up, pair it; no need for iPhoneOTG connect this Android with wired keyboard, choose aosp English keyboard as input method on Androidno need to repeat above steps for reopen this app, but if the PC's changed, it needs to repeat it again; no need for iPhoneMore details and hints can be found in the project's Readme.
GitHubIzzyOnDroid
OUI Lookup and Database
APK
With OUI Lookup you can figure out who manufactured a device simply by inserting its MAC address in the search bar. You can also search for a manufacturer and see its assigned OUIs. Features: Trusted source - The database is sourced from the IEEE to be as correct and updated as possible.Works Offline - OUI Lookup works completely offline, an internet connection is only needed to update the database.Bulk lookup - You can paste a comma/semicolon/whitespace/new line separated list of MAC Addresses to perform a multiple lookup.Auto-paste from the clipboard when there is one or more MAC addressesDark theme is supported
F-DroidGitHub
Octo
APK
Octo is an open-source agile tariff monitor for anyone to see half-hourly tariff rates from Octopus Energy.FeaturesSee half-hourly agile pricesSee kWh/£ usagePrice notificationsCalculate cheapest time to run an applianceHome screen widgets
IzzyOnDroid
OctoPrint for Android
APK
You don't have a Raspberry Pi, but you want to control your 3D printer remotely? Use your phone as an octoprint host! With the Octo4a app you can install Octoprint on your android phone in minutes, without any special Linux knowledge.Features:Quick and easy octoprint installation.Printer connection via USB OTG. Thanks to our custom USB driver you can use octoprint even on phones without root access.Built-in camera support. You can use the built-in camera in your phone to see the progress of your 3D prints, instead of buing a separate module. The app also supports octolapse.SSH support. You can easily log-in via ssh and customize your octoprint installation.
GitHubIzzyOnDroid
OctoTC
APK
OctoTouchController is a dedicated touch screen controller for Octoprint supporting older Android phones / tablets (Android 4.X; device specs: Android 4.x or above, 4inch screen with a minimum resolution of 680x340). Reclaim those old Phones / Tablets that are sitting around that DO NOT have access to the Google store anymore!This is not a replacement for Octoprint but a way to add a touch screen to your printer using old hardware.Add a dedicated touch screen to your 3D printer!Supported Octoprint Plugins include:Cura ThumbnailsPrusa ThumbnailsWLEDPSUControlws281z LEDNote: If you have a version older than 2.x installed on your device, you will need to uninstall that first before being able to install v2.x or higher. A direct update is not possible, and a change of signing keys has been made to prevent it.
GitHubIzzyOnDroid
Odin
APK
# Odin **Odin** is a decentralized peer-to-peer application via the **BitTorrent** network stack. For sharing data, a **pns://** URI is provided, which consists basically of a peer id, which enables others to find your node on the network. ## General The basic characteristics of the app are decentralized, respect of personal data, open source, free of charge, transparent, free of advertising and legally impeccable. ## Documentation **Odin** is a client server implementation and based on the BitTorrent network. The application itself requires the **IPv6** protocol to function properly. When you are behind a router you might be able to switch to the **IPv6** protocol and make the necessary settings, so that your service is globally reachable (Port Forwarding). ### Port Forwarding Port forwarding allows you to specify that all communications received on a certain port are forwarded directly to your device. You set port forwarding rules up on your router. The following list provides information which might be required for the port forwarding. - **Interface** IPv6 Note: Only IPv6 is supported, because a direct connection between two peers can only be established when they use the same IP interface - **Port** 5001 - **Protocol** TCP Note: The protocol is TCP. The direct connection between two peers will be established via a secure TCP connection, protected by a self-signed certificate. - **Application** Odin Note: Usually can be any name ### Concept The application connect to **BitTorrent** network and publish its addresses, so that it can be found by other peers via a unique identifier (pid). This peer identifier () is also used for marking the content via the**pns:///** URI. (Note: is a content identifier) ## Links [Privacy Policy](https://gitlab.com/lp2p/odin/-/blob/master/POLICY.md) [Apache License](https://gitlab.com/lp2p/odin/-/blob/master/LICENSE)
F-Droid
Ojo RTSP IP Camera viewer
APK
Ojo is a basic IP Camera surveillance wall. IP camera's RTSP streams are added via its url and shown in the classic tile configuration. The number of tiles is automatically chosen based on the number of configured cameras: a single camera goes full screen, adding more cameras the app switches to a grid view: 2x2, 3x3, 4x4 and so on. The maximum number of cameras is determined by the device's capabilities. The stream decoding and rendering is demanded to VLC's library: without their effort this app wouldn't be possible. This app was specifically developed for F-Droid, as I couldn't find any open source RTSP viewers in the main repository. The app can be opened deeplinking to url ojo://view To open the app with focus on a specific camera, you can use an intent (it.danieleverducci.ojo.OPEN_CAMERA) to specify which camera you want to view. The extra argument it.danieleverducci.ojo.CAMERA_NAME will open the app with the camera with the name you specified while adding the camera. The extra argument it.danieleverducci.ojo.CAMERA_NUMBER starting at 1 could be used as well, if you have multiple cameras with the same name. See below an example how to use the intent. The flag (-f 268468224) could be useful if you want to switch to another camera while the app is running: adb -s shell am start -a it.danieleverducci.ojo.OPEN_CAMERA -f 268468224 --es it.danieleverducci.ojo.CAMERA_NAME adb -s shell am start -a it.danieleverducci.ojo.OPEN_CAMERA -f 268468224 --es it.danieleverducci.ojo.CAMERA_NUMBER
F-DroidGitHub
Oksigenia SOS
APK
Oksigenia SOS is an offline-first personal safety app for outdoor sports and high-risk environments. No account, no cloud, no Google Services required — everything runs on your device. When something goes wrong, it sends an SMS alert with your GPS coordinates to your emergency contact. No internet connection needed. Smart Fall Detection (Smart Sentinel) The accelerometer monitors you continuously at high frequency. A sudden impact triggers an observation window. If sustained walking movement is detected during that window, the alarm is dismissed automatically — false positives from drops or normal jolts won't fire the SOS. If no rhythmic movement is detected, the SOS is sent. Activity profiles Pick the profile that matches what you're doing — Smart Sentinel adapts its sensitivity: - Trekking / Hiking: balanced default for walking outdoors. - Running (road): tuned for the sustained high-G cadence of road running, with an adaptive rhythm detector. - Trail running / MTB: higher impact threshold for terrain with constant vibration. - Mountaineering: longer observation window for slow recoveries on technical ground. - Paragliding / Kayak / Watersports: automatic fall detection is disabled (the sensor cannot reliably interpret flight or water motion); inactivity monitor and manual SOS remain active. - Professional / Rescue: extended observation window for advanced operational use. Inactivity Monitor (Dead Man's Switch) Set a check-in timer. If you don't confirm you're OK before it expires, the alert is sent automatically. Essential for solo adventures where a fall might leave you conscious but unable to call for help. Live Tracking Send your GPS position by SMS every 30, 60 or 120 minutes. Pause, resume or check in manually at any time — without stopping the monitoring session. Dying Gasp When the battery drops below 5%, a final SMS with your last GPS position is sent automatically before the phone shuts down. Privacy and Compatibility - No account or registration required - All data stays on your device — no cloud sync, no telemetry - No trackers, no analytics, no ads - Works on de-Googled phones (GrapheneOS, MicroG) - Open source under GPLv3 About the permissions Oksigenia SOS asks for sensitive permissions because its job is to call for help when you cannot. Each one maps to a single rescue function: - SMS: sends the alert. SMS is the only channel that works in the mountains without internet. - Location, including "Allow all the time" (background location): when you fall, your phone is in your pocket with the screen off and the app in the background. Without background access, Android can deny a fresh GPS fix at exactly that moment, and the SOS would leave without usable coordinates. Your position is read only when an alert or tracking update is being sent, and it travels exclusively inside the SMS to the contacts you configured — it is never uploaded anywhere. The app's only network use is a version check against a static file on oksigenia.com, which carries no personal data and no location. - Motion sensors / physical activity: fall and inactivity detection. - Battery exemption: so Android doesn't kill the monitoring service mid-route. A safety app that prioritised permission minimalism over getting your coordinates to a rescuer would be failing at its only job. The privacy guarantee here is structural, not cosmetic: everything stays on the device. Available in 11 languages: English, Spanish, French, German, Portuguese, Italian, Dutch, Swedish, Norwegian (Bokmål), Polish and Russian. IMPORTANT: Oksigenia SOS is a support tool and does not replace professional emergency services. Its operation depends on mobile coverage, GPS signal and battery level.
F-DroidGitHubIzzyOnDroid
Ollama
APKDesktop
Open-source framework for running large language models locally on your own hardware.
GitHubIzzyOnDroid
Olvid
APK
Olvid is the first private instant messaging application for everyone. Send messages, photos, files and make secure phone and video calls. What is a "private" messenger? It's a messenger: - That does not push new contacts on you. You are in control: you choose who you want to discuss with. Olvid offers several ways to invite other Olvid users, either face-to-face or remotely. - That does not require any personal data. Olvid won't ask for your phone number, for your email. Unlike your previous messenger, Olvid will never request access to your address book. - On which you will never receive unsolicited messages or messages from an unknown source. - Where all exchanges benefit from the same security and privacy as a real-world discussion behind closed doors. Olvid offers end-to-end encryption and end-to-end authentication by default, always, for everything you send or receive. Olvid guarantees you safe spaces, immune to external aggression, which isolate you from the digital noise and violence of other social networks. Create groups with your family, friends and key collaborators. No spam, no advertising. You finally regain full control over your communications. Olvid has been designed to be the best place to exchange on subjects that matter, with those who matter to you. Olvid - Technology At the heart of Olvid, a 'cryptographic engine' coming from several years of research allows to mathematically prove the integrity, the confidentiality and the anonymity of your communications.
F-DroidGitHub
Open Alert Viewer
APK
Display server and network alerts from servers running Prometheus, Nagios, Icinga or Zabbix. For Linux and Android. Prometheus v0.16.0+, Nagios Core 4.x and Icinga 2.12.0+ are supported with Basic Authentication; partial support, and default authentication for Zabbix 6.x or 7.x.
F-Droid
Open In WhatsApp
APK
Open WhatsApp Chat without saving number to contacts ## Features - You can create a link to open the WhatsApp chat for any number. - Use without saving phone number to contacts - Can also select from Contacts - No app Permissions - Just open the app, enter the number, click the button and the chat will open in WhatsApp - Disclaimer: This app is neither affiliated to nor endorsed by Meta Inc
F-DroidGitHub
OpenDTU
APK
This is a mobile app for the OpenDTU project by tbnobody – a software for ESP32 to talk to Hoymiles Inverters intended to replace the original Hoymiles DTU (Telemetry Gateway) with their cloud access.
GitHubIzzyOnDroid
OpenPods
APK
The Free and Open Source app for monitoring your AirPods on Android. Features: * Shows a notification with AirPods status when they are connected * Respects your privacy * Free and Open Source software * Supports Dark Theme Supported devices: * Apple AirPods 1st gen * Apple AirPods 2nd gen * Apple AirPods 3rd gen * Apple AirPods Pro * Apple AirPods Max * Beats X * Beats Flex * Beats Solo 3 * Beats Studio 3 * Powerbeats 3 * Powerbeats Pro
F-DroidGitHub
OpenWOL
APK
OpenWOL is a simple, private and efficient Wake-on-LAN app for Android. Send a Magic Packet to any device on your local network with a single tap. No account, no cloud, no tracking — everything stays on your device and your local network. FEATURES - Send Wake-on-LAN Magic Packets to wake up devices on your local network - Create automations to trigger a wake up command on a specific SSID (WiFi) connection - Notify (if enabled) when an automation is triggered - Privacy first: no tracking, no ads, zero data collection and fully open-source - No network scanning & no background pings - Simple and straight to the point app PERMISSIONS Location permissions (ACCESS_COARSE_LOCATION, ACCESS_FINE_LOCATION, ACCESS_BACKGROUND_LOCATION) are used exclusively to read the Wi-Fi network name (SSID) in order to trigger automations. Android requires these permissions to access the SSID. No location data is ever collected, stored, or shared. These permissions are only requested when the user enables the optional Automations feature. SETUP 1. Enable Wake-on-LAN in your device's BIOS (look for "Wake on Magic Packet" or "Power On By PCI-E"). 2. On Windows, enable "Wake on Magic Packet" in Device Manager under your network adapter's Advanced properties. 3. Add your device in OpenWOL and tap its card to send a Magic Packet. 4. Optionally, create an Automation to wake your device automatically when connecting to your home Wi-Fi. PRIVACY OpenWOL collects no data. There are no analytics, no ads, no trackers. Location permissions are used only to read the Wi-Fi SSID for automations, no location data is ever stored or shared. Automations are optional and the app works fully without them.
F-Droid
OpenWrt Manager
APK
This app allows you to view the status of your OpenWRT devices using LuCI commands. LuCI must be installed on OpenWRT device. You can connect to multiple devices in the app and select which info is shown. Currently mainly viewing data and status is available. Available actions: Reboot the device. (Devices Page) Disconnect a selected Wi-Fi client from the list (Long press). Restart network interface. It is recommended to enable HTTPS for LuCI on your device.
F-DroidGitHubIzzyOnDroid
Osram Remote
APK
An android app for controlling Osram RGB lights using infrared. Your phone needs to have an IR emitter use this app. Currently only supports built-in IR emitters.
F-DroidGitHub
Otic
APK
Otic lets you stream your Android device's microphone input to the local network using `ServerSocket` and Foreground Service. Otic isn't a receiver, so you must have a custom receiver to receive the audio from the Otic client. Check the README (https://github.com/sakethpathike/Otic/blob/master/README.md) for more details.
F-DroidGitHub
Otoscope
APK
Otoscope is a clean, ad-free replacement for the proprietary apps shipped with cheap Wi-Fi otoscope cameras. The stock companion apps — "AIR-Look" (Wudaopu / Xylla hardware) and "EarVision" (Shenzhen Jiding / JEGOAT hardware) — bundle a dozen ad and analytics SDKs (AdMob, AppLovin, IronSource, MBridge, Vungle, Pangle, Mintegral, etc.) and a sprinkling of in-app tracking. Otoscope reimplements just the connection and viewer functionality, with nothing else. Features: * Discover the camera over Bluetooth Low Energy. * Join the camera's Wi-Fi access point in a one-process scope, so the rest of your traffic isn't affected. * Live video stream, decoded in-app over the camera's UDP protocol — pure Kotlin, no FFmpeg, no native blobs. * Auto-rotation driven by the camera's on-board accelerometer / gyro. * Horizontal-mirror toggle for self-examination. * Circular mask matching the otoscope lens. Supported hardware families (the right protocol is selected automatically from the BLE advertisement): * Wudaopu / Xylla — Wi-Fi SSID `Enjoy-XXXXXX` or `JesHome-XXXX`, open AP. * Shenzhen Jiding / JEGOAT — Wi-Fi SSID `softish-XXXXXX`, WPA2. Otoscope is GPL-3.0-or-later and contains no third-party trackers, ad SDKs, or proprietary native libraries.
F-DroidGitHub
PAIesque
APK
PAIesque helps athletes and fitness enthusiasts monitor their training through a simple three-step logic: 1. Measure training impulse (TRIMP) — The faster and longer your heart beats, the higher your daily score. 2. Analyze patterns over time — Track how your TRIMP accumulates and distributes 3. Monitor your body's response — Compare how your body reacts to training load PAIesque is different from commercial fitness apps (e.g. Garmin, Whoop, Polar). Every metric comes from published, peer-reviewed research with transparent methods that can be calculated from heart rate data alone. The app only includes metrics we can verify and reproduce from first principles — no proprietary black boxes, no undisclosed algorithms. And, all your data stays on your device. 1. TRIMP: • Banister TRIMP — The original exponential model with sex-specific coefficients (a=0.64/0.86, b=1.92/1.67) [Banister, 1991; Morton et al., 1990] • iTRIMP — Individualized TRIMP with customizable b coefficient (1.5-4.0) [Stagno et al., 2007; Akubat et al., 2012] • LT-TRIMP — Lactate Threshold-based model with β coefficient (0.04-0.11) and smooth transition at LT [Cheng et al., 1992; Mader et al., 1976; Gaesser and Poole, 1986] • PAI-esque — PAI-inspired metric using EWMA (not the official commercial algorithm) [Nes et al., 2017; Kieffer et al., 2021] 2. Patterns over time: • Intensity zones — Time and TRIMP spent in low/moderate/high zones (polarized training model) [Seiler and Tønnessen, 2009; Stöggl and Sperlich, 2014] • EWMA — Exponentially Weighted Moving Average for rolling loads (more sensitive than simple averages) • ACWR — Acute:Chronic Workload Ratio for injury risk monitoring (0.8-1.3 = sweet spot) [Murray et al., 2017; Griffin et al., 2021; Gabbett, 2016] • Polarized Training Score — 0-100 measure of how closely your distribution matches your targets 3. Body's response: • Resting Heart Rate (RHR) — Calculated from your defined sleep window (adaptive percentile: 5th-15th) • Heart Rate Variability (HRV) — Daily RMSSD averages during sleep [Task Force, 1996; Plews et al., 2013; Buchheit, 2014] • EWMA trends — Exponentially weighted moving averages for both RHR and HRV (acute and chronic windows) • Combined interpretation — RHR ↓ + HRV ↑ = positive adaptation; RHR ↑ + HRV ↓ = possible fatigue Data Management: • CSV export/import • Complete backup/restore (db) • All data stays on your device — no accounts, no cloud uploads, no tracking Creative Use Cases: • Coach analyzing athletes — Import athlete exports, analyze charts, provide feedback • Research analysis — Export CSV files for custom analysis in R, Python, or spreadsheets • Switch between athletes — Use "Delete All Data" + CSV import to analyze multiple individuals Requirements: • Google Health Connect installed on your device • Heart rate (and HRV) data in Health Connect from your wearable device (Gadgetbridge, Garmin, Polar, Samsung, etc.) • Android 8.0 (API 26) or higher Note on PAI: Our PAI-esque implementation is NOT the official commercial PAI® algorithm (which is proprietary). It uses EWMA and scaled TRIMP values to provide a similar intensity-weighted weekly score. The 100 PAI target remains the evidence-based health outcome from the HUNT Study research.
F-Droid
PAssist
APK
PAssist supports you in providing on-call service in conjunction with an SMS-based alerting system.The application is automatically activated via defined on-call service events in your calendar and performs the following functions during the on-call duties:Triggering of an alarm on the receipt of an SMS from the operations center as well as acknowledgment via SMS after the confirmation of the alarm by the user.Monitoring of the phone signal level and notification in case of bad or off signal level.Automatically control of the ringtone volume based on your day and night profile.Logging of alert incidents with start and end time as well as all associated SMS messages.Monitoring and acknowledgment of periodic test alarms for testing the alarm chain from end to end.Other functions that are available regardless of the current on-call state:On-call event calenderHistory of all alert incidentsIn order to perform the functions of PAssist, PAssist needs to be able to receive and send SMS. As these SMS permissions are no more granted by Google, a compatible SMS adapter is required - S2MSP.
GitHubIzzyOnDroid
PWS Watcher
APK
PWS Watcher allows you to monitor the data generated by PWS. The application allows the monitoring of multiple weather stations simultaneously. It works with …realtime.txt generated by Cumulus MXclientraw.txt generated by Weather Displaydaily.csv generated by Ambient WeatherXML file generated by WeeWX
GitHubIzzyOnDroid
PadConnect
APK
PadConnect is a tool that allows you to connect your Android device to your PC(Windows Only) and use it as a gamepad. It supports wireless connection, and it is compatible with a wide range of games. With PadConnect, you can enjoy your favorite games on your PC(Windows Only) using your Android device as a controller.
F-DroidGitHub
Paintball Notificator
APK
Simple app to let you know when all teams are ready.
F-DroidGitHub