Case Study P2P Sats

Every public Bitcoin offer, in one live order book.

P2P Sats pulls offers from five peer-to-peer Bitcoin marketplaces into a single live price view over nostr. Nine currencies, three languages, no account, and an alert that reaches you the moment a deal matches. We built it end to end and run it in the open.

Client
P2P Sats
Sector
Bitcoin · P2P markets
Engagement
Solo end-to-end build
Stage
Live · open source
Platform
Web app · in-browser
The P2P Sats live order book showing mid price, best bid and ask, spread and a depth chart across five Bitcoin marketplaces
One live book: best bid and ask, spread, depth, and crossed pairs across five P2P markets.
By the numbers
5P2P markets unified
9Fiat currencies
3Languages
0Accounts to create

The best Bitcoin price is hiding across five separate marketplaces.

Trading Bitcoin person to person keeps your details off a big exchange. The catch is that the offers sit in five different places, and each marketplace shows only its own book.

To find a good price on mostro, lnp2pbot, RoboSats, Peach or HodlHodl, you open all five and compare by eye. Most people give up halfway, so real deals go unseen and the spread you actually trade at is worse than the spread on offer.

The offers also move. A seller edits a price, a marketplace re-publishes it, a duplicate appears under a new id. Any view that wants to be trustworthy has to keep up with all of that in real time.

One live book, merged in your browser, no account in the way.

The five marketplaces publish their offers to nostr relays using NIP-69, a shared format for peer-to-peer orders. We read those relays directly, parse each offer, drop the duplicates, and merge everything into a single price view with a depth chart, all client-side.

What that meant in practice

  • One live order book across five P2P markets, deduplicated as offers change
  • A depth chart, plus a crossed-pair detector that flags arbitrage between two markets
  • Nine fiat currencies and three languages, with no account to create
  • An always-on watcher that emails you, or sends a nostr DM, when an offer matches
The P2P Sats alert builder: choose a side, currency and premium, then pick email or nostr DM delivery
Alerts

Tell it the deal you want, then close the tab.

Set a side, a currency and a premium, and choose email or a nostr DM. The watcher runs on a server long after you leave the page, so when an offer crosses your threshold you hear about it without refreshing anything.

Always-on watcher · email or nostr
See it work

Walkthrough: the live book, the depth chart, crossed-pair detection, and setting an alert

Inside the product
P2P Sats — the full order book with bids and asks, premiums, amount ranges and payment methods, plus a crossed-pairs banner
An alert email from P2P Sats describing a matched offer: side, currency, premium, fiat range and payment methods
The hardest part

Five markets describe the same offer in different shapes, edit it, and re-publish seconds later. We reconcile that mess into one trustworthy book in the browser, then read across markets for the case where a buyer on one will pay more than a seller on another will take.

Ego Eimi Engineering note · the build

Live, pulling real offers, and open for anyone to read.

P2P Sats went live on May 13 and has had a few weeks in the world, with around 212 visitors so far.

The traction is early, so the product carries the case. Open the site and you see real offers from five markets right now, priced in your currency, with no sign-up between you and the book. The code is public under an MIT license, with Nelson as the sole contributor, so anyone can audit how the prices are sourced.

Vue TypeScript Nostr NIP-69 Node WebSockets
Our role
Design, architecture, front and back end
Team
Solo build
Model
Open source · MIT
Status
Live, evolving
Project partner Nelson P.
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