FOSS apps: free and open source

Free and open-source software: the source code is public under an open licence.

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PsstPsst

Decentralized, end-to-end encrypted messaging
- Communication
- FOSS
- Free
- Nostr
- Android only
Zapstore GitHub
Pubky Ring

Pubky Ring is the key manager for your identity in the Pubky ecosystem.
- System & tools
- FOSS
- Free
- Android only
Zapstore Google Play Aurora Store GitHub
Punch Up

A boxing-themed Android app that visualizes real-time Bitcoin markets: Satoshi (hero) vs Lizard (villain), driven by live price and…
- Finance
- FOSS
- Free
- Android only
Zapstore Google Play Aurora Store
Pure Signal

Bitcoin-only news
- Finance
- FOSS
- Free
- Android only
Zapstore GitHub
purrmint

Mobile Cashu Mint - Run your own Cashu mint directly on your Android phone!
- Finance
- FOSS
- Free
- Android only
Zapstore GitHub
PurrWallet

PurrWallet is a powerful cashu ecash wallet built with Rust + Flutter, powered by CDK!
- Finance
- FOSS
- Free
- Android only
Zapstore GitHub
Pushstr

Private Nostr-based messaging across browser and mobile
- Communication
- FOSS
- Free
- Nostr
- Android only
Zapstore
Radius

Post a small job nearby, or earn the cash doing one. Over Bluetooth, no server.
- Communication
- FOSS
- Free
- Nostr
- Android only
Zapstore
Readstr

Speed reading app
- Education
- FOSS
- Free
- Android only
Zapstore GitHub
RedWallet (XBT Beta)

A self-custody Bitcoin (XBT) wallet with Taproot, cold PSBT signing and fee bumps — tester beta.
- Finance
- FOSS
- Free
- Android only
Zapstore
Relay Tools

Browse, search and manage nostr relays.
- Communication
- FOSS
- Free
- Nostr
- Android only
Zapstore
Ridestr

Rideshare, without the middleman.
- Finance
- FOSS
- Free
- Nostr
- Android only
Zapstore GitHub
Roadstr

Roadstr is an open-source, decentralised navigation app for Android, built on the Nostr protocol.
- Navigation
- FOSS
- Free
- Nostr
- Android only
Zapstore GitHub
Roblosats

A simple and private bitcoin exchange, on the BLAKE2b chain
- Android only
Zapstore GitHub
Robosats

A simple and private bitcoin exchange
- Android only
Zapstore IzzyOnDroid GitHub
RUNSTR

Fitness competitions with rewards
- Android only
Zapstore GitHub
RUNSTR

A running app built on the Nostr protocol. Track runs, view a global feed, and listen to Wavlake music.
- Health & fitness
- FOSS
- Free
- Nostr
- Android only
Zapstore GitHub
Sachwert-Tresor

Local, encrypted vault for your Bitcoin, gold and silver — fully offline.
- Finance
- FOSS
- Free
- Android only
Zapstore GitHub
SaintStream

Automatically share what you're listening to on Nostr.
- Multimedia
- FOSS
- Free
- Nostr
- Android only
Zapstore
Samiz

BLE mesh for nostr notes when the internet is down.
- Communication
- FOSS
- Free
- Nostr
- Android only
Zapstore GitHub
Sandboxed

Mobile mission control for self-hosted AI coding agents
- System & tools
- FOSS
- Free
- Android only
Zapstore GitHub
Sats Tracker

Expense tracker app for people living the Bitcoin Standard.
- Finance
- FOSS
- Free
- Android only
Zapstore GitHub
SatScream

Live Bitcoin price with customizable pump/dump alerts
- Finance
- FOSS
- Free
- Nostr
- Android only
Zapstore GitHub
SatsPrice

Bitcoin price calculator app
- Finance
- FOSS
- Free
- Android only
Zapstore GitHub
Scriptwerk

Bitcoin-Miniscript-Studio für Android — Core-RPC und eigenes Fulcrum über TLS
- Finance
- FOSS
- Free
- Android only
Zapstore GitHub
Self-sown Vendor

A global, permissionless marketplace for food freedom.
- Finance
- FOSS
- Free
- Nostr
- Android only
Zapstore
S
Sextant

Native MongoDB client for Android
- System & tools
- FOSS
- Free
- Android only
Zapstore GitHub
Shake To Call / Answer

Shake your phone to call a predefined number or answer calls
- Communication
- FOSS
- Free
- Android only
Zapstore Google Play Aurora Store GitHub
Shakespeare

Build custom apps with AI, right from your browser.
- Internet
- FOSS
- Free
- Nostr
- Android only
Zapstore
SHOCKWALLET

ShockWallet is a self-custody Lightning wallet that uses Nostr to securely connect, share, and manage remote nodes—enabling powerful…
- Finance
- FOSS
- Free
- Nostr
- Android only
Zapstore Google Play Aurora Store GitHub
Signer Guide

Bitcoin staking for STX: lock in your own wallet, earn sats every week.
- Finance
- FOSS
- Free
- Android only
Zapstore GitHub
Signet

NIP-46 remote signer for Nostr
- Security & privacy
- FOSS
- Free
- Nostr
- Android only
Zapstore
SilentSuite

End-to-end encrypted sync for calendar, contacts, and tasks
- Productivity
- FOSS
- Free
- Android only
Zapstore Google Play Aurora Store GitHub
Simulador SeedSigner

Simulador educativo de SeedSigner: firmware real en el navegador. NO es un monedero
- Finance
- FOSS
- Free
- Android only
Zapstore
Sister Charge

Track battery stats and sync to Nostr.
- Security & privacy
- FOSS
- Free
- Nostr
- Android only
Zapstore
SkateSpots

The decentralized skate map & community, built on Nostr
- Communication
- FOSS
- Free
- Nostr
- Android only
Zapstore
S
SMS2Webhook

Forwards incoming SMS to a webhook endpoint you control, with retries, deduplication and optional API key authentication.
- Communication
- FOSS
- Free
- Android only
Zapstore GitHub
Snort

Nostr social client
- Communication
- FOSS
- Free
- Nostr
- Android only
Zapstore Google Play Aurora Store GitHub
S
Solar Dial

Private, offline apparent-solar-time clock and true-azimuth instrument.
- Android only
Zapstore GitHub
Sonar

Private messenger — Bluetooth nearby, Nostr everywhere, Lightning in-chat
- Finance
- FOSS
- Free
- Nostr
- Android only
Zapstore
SpecieSnapp

Know what it is. Instantly. Identify plants, animals, fungi & insects
- Finance
- FOSS
- Free
- Android only
Zapstore
StableKraft

Music & podcast aggregator with Nostr and Lightning
- Multimedia
- FOSS
- Free
- Nostr
- Android only
Zapstore GitHub
Staircase

Private, end-to-end encrypted group chat over Nostr
- Communication
- FOSS
- Free
- Nostr
- Android only
Zapstore
Stash

Nostr social bookmarking and highlights for Android
- Education
- FOSS
- Free
- Nostr
- Android only
Zapstore
Submarine

Your passwords, encrypted and synced. No account needed.
- Security & privacy
- FOSS
- Free
- Nostr
- Android only
Zapstore GitHub
Sun Day

Real‑time UV data, personalized Vitamin D calculations, and a day‑night UI to boost Vitamin D while reducing sun risk.
- System & tools
- FOSS
- Free
- Android only
Zapstore GitHub
SunApp

Sun times and solar alarms for anywhere on Earth, computed entirely offline
- Android only
Zapstore GitHub
Surveil

Magic: The Gathering cards on Nostr
- System & tools
- FOSS
- Free
- Nostr
- Android only
Zapstore