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Developer Tools

This page covers tools that help you build, test, and debug Nostr applications.

Command Line Tools​

nak​

Swiss army knife for Nostr.

Install:

go install github.com/fiatjaf/nak@latest

Usage:

# Generate keys
nak key generate
nak key public <nsec>

# Fetch events
nak req -k 1 -l 10 wss://relay.damus.io

# Publish event
echo '{"kind":1,"content":"Hello!"}' | nak event wss://relay.damus.io

# Decode NIP-19
nak decode npub1...

# Verify event
cat event.json | nak verify

nostril​

Simple event creator.

# Create and sign a note
nostril --sec <hex-secret> --content "Hello Nostr"

# Create with envelope for relay
nostril --sec <hex-secret> --envelope --content "Hello" | websocat wss://relay.damus.io

nostr-tools CLI​

CLI from nostr-tools package.

npx nostr-tools generate-key
npx nostr-tools sign-event <event.json>

Browser Extensions​

Alby​

Lightning + Nostr browser extension.

  • Website: getalby.com
  • Browsers: Chrome, Firefox, Safari

Features:

  • NIP-07 signing
  • Lightning wallet
  • Budget controls
  • Multiple accounts

nos2x​

Minimal Nostr signing extension.

Features:

  • Lightweight
  • Pure NIP-07
  • Open source

Flamingo​

Full-featured Nostr extension.

Features:

  • NIP-07 signing
  • NIP-44 encryption
  • Multiple keys

Testing Tools​

WebSocket Test Clients​

websocat​

CLI WebSocket client.

# Install
cargo install websocat

# Connect to relay
websocat wss://relay.damus.io

# Send subscription
["REQ","test",{"kinds":[1],"limit":5}]

wscat​

Node.js WebSocket client.

npm install -g wscat

wscat -c wss://relay.damus.io
> ["REQ","sub1",{"kinds":[1],"limit":3}]

Relay Testing​

nostr-relay-tester​

Test relay NIP compliance.

npx nostr-relay-tester wss://relay.example.com

relay-tools​

Relay inspection utilities.

# Check relay info
curl -H "Accept: application/nostr+json" https://relay.example.com/

# Test connection
websocat wss://relay.example.com/ -n

Development Environments​

Local Relay for Testing​

Run a local relay for development:

# Using strfry
docker run -p 7777:7777 hoytech/strfry

# Using nostream
docker run -p 7777:7777 cameri/nostream

Mock Relay​

For unit testing:

import { createMockRelay } from 'nostr-tools/mock';

const relay = createMockRelay();
// Returns events you've injected

Debugging​

Event Inspector​

Paste events to decode:

// Browser console
const event = JSON.parse('{"id":"...","pubkey":"..."}');

// Decode pubkey
import { nip19 } from 'nostr-tools';
console.log(nip19.npubEncode(event.pubkey));

// Verify signature
import { verifyEvent } from 'nostr-tools/pure';
console.log(verifyEvent(event));

Network Debugging​

Chrome DevTools:

  1. Open Network tab
  2. Filter by WS (WebSocket)
  3. Click connection to see messages

Firefox:

  1. Open Network tab
  2. Filter by WS
  3. View Messages panel

Common Debug Patterns​

// Log all relay messages
relay.onmessage = (msg) => {
  console.log('Received:', JSON.parse(msg.data));
};

// Track subscriptions
const subs = new Map();
function subscribe(id, filter) {
  console.log(`Subscribe ${id}:`, filter);
  subs.set(id, filter);
}

Key Management​

Key Generation​

# Using nak
nak key generate

# Using openssl
openssl rand -hex 32

Bech32 Encoding​

# Encode pubkey to npub
echo "pubkey-hex" | nak encode npub

# Decode npub to hex
nak decode npub1...

Mnemonic (BIP-39)​

import { generateMnemonic, mnemonicToEntropy } from '@scure/bip39';
import { wordlist } from '@scure/bip39/wordlists/english';

const mnemonic = generateMnemonic(wordlist);
console.log(mnemonic);
// witch collapse practice feed shame open despair creek road again ice least

API Tools​

Nostr.band API​

Query aggregated Nostr data.

# Search notes
curl "https://api.nostr.band/v0/search?q=bitcoin&limit=10"

# Get trending
curl "https://api.nostr.band/v0/trending/notes"

# Get profile
curl "https://api.nostr.band/v0/p/npub1..."

Primal API​

Cached Nostr data access.

curl "https://primal.net/api/feed/latest"

Monitoring​

nostr.watch​

Features:

  • Relay uptime monitoring
  • NIP support detection
  • Performance metrics

Relay Stats​

Track your relay's metrics:

# Prometheus endpoint (if supported)
curl http://localhost:7777/metrics

# Relay info
curl -H "Accept: application/nostr+json" http://localhost:7777/

Useful Utilities​

Event ID Calculation​

import { getEventHash } from 'nostr-tools/pure';

const event = {
  pubkey: '...',
  created_at: Math.floor(Date.now() / 1000),
  kind: 1,
  tags: [],
  content: 'test'
};

const id = getEventHash(event);

NIP-05 Verification​

# Check NIP-05 identifier
curl "https://example.com/.well-known/nostr.json?name=alice"

Relay List Discovery​

// Get user's relay list (NIP-65)
const filter = {
  kinds: [10002],
  authors: [pubkey],
  limit: 1
};

See Also​