Noxtr Specification Sheet

What is Noxtr?

Noxtr is a web-based Nostr client integrated into the ExtFW PHP framework. It runs as a module within a self-hosted website, combining Nostr protocol access with server-side features like user accounts, Lightning address hosting, and NIP-05 identity verification.

It is designed as a single-page application with no external JavaScript frameworks — vanilla JS with a lightweight DOM helper (wquery).

Key Characteristics

NIP Support

Nostr Implementation Possibilities (NIPs) supported by Noxtr:

Event Kinds

Feature Overview

Client Comparison

An impartial comparison of Noxtr against established Nostr clients. Each client has different strengths — this table aims to be factual, not promotional.

General

Core NIP Support

Features

Known Limitations (not for long)

Areas where Noxtr is behind other clients:

• NIP-17 (Modern DMs) — Still uses NIP-04. Most modern clients have moved to NIP-17/NIP-44 for DMs, which provides better metadata protection.
• NIP-96 (File Upload) — No support for decentralized file storage. Image uploads go to the host server only.
• NIP-47 (Wallet Connect) — No NWC integration. Zaps rely on internal balance or BTCPay.
• NIP-72/29 (Communities/Groups) — No moderated communities or relay-based group support.
• Multiple accounts — No instant account switcher. Changing accounts requires logout and re-login, but is possible.
• Outbox model — No per-user relay routing. All subscriptions go to the configured relay pool.
• No native app — Web only, but works on mobile via browser and supports “Add to Home Screen” for an app-like experience. No push notifications.

Distinctive Strengths

• Self-hosted identity — NIP-05 and Lightning addresses served from your own domain, auto-configured.
• Zero-dependency frontend — No npm, no build tools, no framework. Deploy by copying files.
• Internal zap transfers — Registered users can zap each other without Lightning network fees.
• NIP-28 channels — One of the few web clients with full public chat support (create, join, pin, invite links, delete own messages).
• NIP-23 articles — Long-form content integrated in the main feed with replaceable-event deduplication, Markdown rendering, and a dedicated composer with title/summary/image fields.
• Topic-based feed filtering — Subscribe to hashtags and filter your global feed without following specific users.
• AR mesh profile rendering — The only Nostr client that parses and renders AR collaboration/mesh profile broadcasts as visual cards.
• Dead domain detection — Automatically detects and gracefully handles dead image CDNs with 24h retry.
• NIP-46 with QR + persistence — Full Nostr Connect flow with QR code, localStorage persistence across sessions.
• Server-side Lightning — LNURL-pay endpoint with BTCPay integration and auto-generated server keypair for zap receipts.
• Built-in P2P Bitcoin trading (Mostro / NIP-69) — The only web Nostr client with native support for buying Bitcoin P2P via the Mostro protocol, with a step-by-step guided flow and per-order plain-language explanations — designed to be beginner-friendly.

₿itcoin P2P — Mostro

Noxtr includes native support for Mostro, a peer-to-peer Bitcoin exchange protocol built on top of Nostr. You can buy or sell Bitcoin directly with other people, with no inter/mediaries or custodians, paying by bank transfer, cash, or any other agreed method.

The P2P ₿ tab in the navigation bar gives you access to the live order book with all available offers.

How to buy Bitcoin (step by step)

No prior Bitcoin experience needed. You only need a Lightning wallet on your phone (Phoenix, Breez, Zeus, Wallet of Satoshi…).

1. Open the P2P ₿ tab — You’ll see a list of sell offers with amount, currency, and payment method.
2. Choose an offer that suits you (amount, payment method) and press Buy.
3. Enter your Lightning Address (e.g. user@wallet.com) or a bolt11 invoice generated from your wallet — that is where you will receive the sats.
4. The robot takes over: it locks the seller’s Bitcoin and tells you how much to pay in fiat and how.
5. Send the money to the seller via the indicated method (bank transfer, cash, etc.) and press Fiat sent.
6. The seller confirms receipt of the fiat payment and presses Release sats.
7. Done! The sats arrive in your Lightning wallet. The trade appears as completed in its card.

If the seller’s wallet or the robot’s node cannot route the payment to your address, the trade card will show a field to enter an alternative Lightning address. Your sats are always safe with the robot.

How to sell Bitcoin

1. Press New order in the P2P ₿ tab and choose Sell BTC.
2. Configure the offer: fiat amount, currency, accepted payment method, and amount type (fixed or range).
3. Publish the order. It will appear in the order book for others to take.
4. When someone takes it, the robot sends you a hold invoice. Pay it from your Lightning wallet — the sats will be locked, not charged, until the trade finishes.
5. Give the buyer your payment details and wait to receive the fiat via the agreed method.
6. When the fiat arrives, press Release sats. The robot will send them to the buyer.

Import identity from Mostro Mobile

If you already use the Mostro Mobile app, you can import your identity into Noxtr without creating a new account:

1. On the Noxtr login screen, press 📲 Mostro Mobile.
2. Enter your 12-word seed phrase (the same phrase you use in Mostro Mobile).
3. Noxtr will derive your Nostr private key using the same standard as Mostro Mobile (BIP39 + BIP32, path m/44'/1237'/38383'/0/0).
4. Your active trades will be automatically recovered by sending a restore message to the robot.

Completed trades (cancelled or finished) are not recovered because the robot does not track them. Past history is only available if the same 12 words and interface initiated those trades.

Reputation and ratings

After completing a trade you can rate the counterpart from 1 to 5 stars. Ratings received appear in your reputation card (⭐ average · number of trades). Mostro robots publish each user’s accumulated reputation alongside their order book entries.

For administrators — Mostro P2P

Server Monitor — Notifications & Auto-take

The Monitor is a PHP process that runs in the background on the server and watches active Mostro trades even when no user has the web app open. It listens to Nostr relays continuously and acts whenever it receives relevant events.

For users — What does the Monitor do for you?

If the site administrator has the Monitor running, you will receive automatic alerts whenever something happens in your trades:

Each notification is sent once per trade and event type — no spam.

Link Telegram to receive alerts

1. Go to the Telegram section of the web app.
2. Press Link Telegram.
3. On mobile: tap the “Open bot in Telegram” link — the bot chat opens directly and you just press Start.
4. On desktop: copy the /start CODE command shown on screen and paste it into the bot chat in Telegram.
5. The bot will confirm the link. From that moment on you will receive alerts for new private messages in Noxtr.

For administrators — Starting and stopping the Monitor

The Monitor is managed from the web admin panel (/noxtr/server_admin) via the Start / Stop / Status buttons, or directly from the server console:

php /path/index.php noxtr/server/action=monitor --verbose

To keep it running in the background:

nohup php /path/index.php noxtr/server/action=monitor > /var/log/monitor.log 2>&1 &

For administrators — Control commands via Nostr DM

The Monitor has its own Nostr identity. Authorized administrators can send it plain-text commands via DM from any Nostr client (including Noxtr). Its npub appears in the startup message and in the web panel.

For administrators — New order notifications

In addition to watching user trades, the Monitor notifies the administrator of every new order that appears in the Mostro order book:

• Nostr DM to the administrator’s npub with an order summary.
• Telegram with full details: ID, type (BUY/SELL), amount, payment method, and robot age.
• Email with the same information in HTML format.

To receive new-order notifications via Telegram, the administrator must have the bot linked and their Nostr pubkey added to admin_pubkeys in the Monitor configuration.

For administrators — Auto-take

The Monitor can automatically take orders that match configured rules. This is useful for scenarios such as “always take orders from 0-day robots” or “always take orders for exactly 88 EUR”.

Auto-take is ephemeral: the Monitor generates a temporary keypair, takes the order, and notifies the admin, but does not create a persistent trade in the database. Subsequent tracking of the trade must be done manually from another Mostro client.

Technical Architecture