Mostro

Mostro is a non-custodial peer-to-peer Bitcoin exchange built on Lightning and nostr. Orders travel as nostr events and settlement happens over Lightning, without KYC and without a central order-book operator holding user funds. Mostro grew out of lnp2pBot, the Telegram-based peer-to-peer exchange used widely across Latin America, and keeps the same trading model while replacing the closed transport with an open protocol.

The system is built around multiple independent Mostro nodes that anyone can run. Each node operates its own Lightning node, publishes its order book to nostr relays, and coordinates trades between buyers and sellers. Clients talk to any node through standard nostr events, so users can choose which operator to trade through. Order events follow NIP-69, an interoperable peer-to-peer order standard that Mostro contributed upstream, and the full message format lives in the open protocol specification.

Trades use NIP-59 gift-wrapped messages so relays cannot see who is talking to whom, clients rotate their trade keys on every order to break linkability across trades, and the node's database encrypts private keys and sensitive columns at rest.

Reference implementations include the Mostro node, a Flutter mobile app, a Ratatui terminal UI (Mostrix), a CLI, and a browser-based admin/signing tool (mostro-webtool). The protocol supports dispute resolution with third-party solvers, and Mostro Score computes public reliability metrics for each node operator so users can pick someone they trust.

Why fund it?

For users in authoritarian regimes, a resilient way to buy and sell Bitcoin peer-to-peer is critical infrastructure. Telegram bots worked but depended on a single platform that could be blocked or coerced; Mostro moves the same workflow onto nostr, where no single operator can shut it down.

Running trading on an open protocol also lets anyone build clients, from mobile apps to terminal UIs to interfaces tailored to a specific local community.

OpenSats supported Mostro in the second wave of nostr grants in 2024 and renewed the grant in 2025. The project is also supported by the Human Rights Foundation, and the newly formed Mostro Foundation handles donations and distributes funds to contributors.

What's next?

The mobile app reached public beta in early 2026 and now ships for Android through Zapstore and direct APK downloads, with desktop builds for Linux, macOS, and Windows attached to every release. Multi-node support landed in v1.1.1, so users can already switch between independent Mostro operators from inside the app. The Mostro daemon also runs a transparent "development fund" where a small configurable trade fee flows to contributors, audited through public nostr events.

Ongoing work focuses on shipping the iOS client, maturing the Mostro Score dashboard, hardening dispute resolution, and packaging Mostro for Start9 so anyone can run a node on their own hardware.