nostr-tools

Tools for developing Nostr clients.

Only depends on @scure and @noble packages.

This package is only providing lower-level functionality. If you want an easy-to-use fully-fledged solution that abstracts the hard parts of Nostr and makes decisions on your behalf, take a look at NDK and @snort/system.

Installation

 npm install nostr-tools # or yarn add nostr-tools

If using TypeScript, this package requires TypeScript >= 5.0.

Usage

Generating a private key and a public key

import { generateSecretKey, getPublicKey } from 'nostr-tools'

let sk = generateSecretKey() // `sk` is a Uint8Array
let pk = getPublicKey(sk) // `pk` is a hex string

Creating, signing and verifying events

import { finalizeEvent, verifyEvent } from 'nostr-tools'

let event = finalizeEvent({
  kind: 1,
  created_at: Math.floor(Date.now() / 1000),
  tags: [],
  content: 'hello',
}, sk)

let isGood = verifyEvent(event)

Interacting with a relay

import { relayConnect, finalizeEvent, generateSecretKey, getPublicKey } from 'nostr-tools'

const relay = await relayConnect('wss://relay.example.com')
console.log(`connected to ${relay.url}`)

// let's query for an event that exists
const sub = relay.subscribe([
  {
    ids: ['d7dd5eb3ab747e16f8d0212d53032ea2a7cadef53837e5a6c66d42849fcb9027'],
  },
], {
  onevent(event) {
    console.log('we got the event we wanted:', event)
  },
  oneose() {
    sub.close()
  }
})

// let's publish a new event while simultaneously monitoring the relay for it
let sk = generateSecretKey()
let pk = getPublicKey(sk)

let sub = relay.sub([
  {
    kinds: [1],
    authors: [pk],
  },
])

sub.on('event', event => {
  console.log('got event:', event)
})

let event = {
  kind: 1,
  created_at: Math.floor(Date.now() / 1000),
  tags: [],
  content: 'hello world',
}

// this assigns the pubkey, calculates the event id and signs the event in a single step
const signedEvent = finalizeEvent(event, sk)
await relay.publish(signedEvent)

let events = await relay.list([{ kinds: [0, 1] }])
let event = await relay.get({
  ids: ['44e1827635450ebb3c5a7d12c1f8e7b2b514439ac10a67eef3d9fd9c5c68e245'],
})

relay.close()

To use this on Node.js you first must install websocket-polyfill and import it:

import 'websocket-polyfill'

Interacting with multiple relays

import { SimplePool } from 'nostr-tools'

const pool = new SimplePool()

let relays = ['wss://relay.example.com', 'wss://relay.example2.com']

let h = pool.subscribeMany(
  [...relays, 'wss://relay.example3.com'],
  [
    {
      authors: ['32e1827635450ebb3c5a7d12c1f8e7b2b514439ac10a67eef3d9fd9c5c68e245'],
    },
  ],
  {
    onevent(event) {
      // this will only be called once the first time the event is received
      // ...
    },
    oneose() {
      h.close()
    }
  }
)

await Promise.any(pool.publish(relays, newEvent))
console.log('published to at least one relay!')

let events = await pool.querySync(relays, [{ kinds: [0, 1] }])
let event = await pool.get(relays, {
  ids: ['44e1827635450ebb3c5a7d12c1f8e7b2b514439ac10a67eef3d9fd9c5c68e245'],
})

Parsing references (mentions) from a content using NIP-10 and NIP-27

import { parseReferences } from 'nostr-tools'

let references = parseReferences(event)
let simpleAugmentedContent = event.content
for (let i = 0; i < references.length; i++) {
  let { text, profile, event, address } = references[i]
  let augmentedReference = profile
    ? `<strong>@${profilesCache[profile.pubkey].name}</strong>`
    : event
    ? `<em>${eventsCache[event.id].content.slice(0, 5)}</em>`
    : address
    ? `<a href="${text}">[link]</a>`
    : text
  simpleAugmentedContent.replaceAll(text, augmentedReference)
}

Querying profile data from a NIP-05 address

import { nip05 } from 'nostr-tools'

let profile = await nip05.queryProfile('jb55.com')
console.log(profile.pubkey)
// prints: 32e1827635450ebb3c5a7d12c1f8e7b2b514439ac10a67eef3d9fd9c5c68e245
console.log(profile.relays)
// prints: [wss://relay.damus.io]

To use this on Node.js < v18, you first must install node-fetch@2 and call something like this:

nip05.useFetchImplementation(require('node-fetch'))

Encoding and decoding NIP-19 codes

import { nip19, generateSecretKey, getPublicKey } from 'nostr-tools'

let sk = generateSecretKey()
let nsec = nip19.nsecEncode(sk)
let { type, data } = nip19.decode(nsec)
assert(type === 'nsec')
assert(data === sk)

let pk = getPublicKey(generateSecretKey())
let npub = nip19.npubEncode(pk)
let { type, data } = nip19.decode(npub)
assert(type === 'npub')
assert(data === pk)

let pk = getPublicKey(generateSecretKey())
let relays = ['wss://relay.nostr.example.mydomain.example.com', 'wss://nostr.banana.com']
let nprofile = nip19.nprofileEncode({ pubkey: pk, relays })
let { type, data } = nip19.decode(nprofile)
assert(type === 'nprofile')
assert(data.pubkey === pk)
assert(data.relays.length === 2)

Import modes

Using just the packages you want

Importing the entirety of nostr-tools may bloat your build, so you should probably import individual packages instead:

import { generateSecretKey, finalizeEvent, verifyEvent } from 'nostr-tools/pure'
import { matchFilter } from 'nostr-tools/filter'
import { decode, nprofileEncode, neventEncode, npubEncode } from 'nostr-tools/nip19'
// and so on and so forth

Using it with nostr-wasm

nostr-wasm is a thin wrapper over libsecp256k1 compiled to WASM just for hashing, signing and verifying Nostr events.

import { setNostrWasm, generateSecretKey, finalizeEvent, verifyEvent } from 'nostr-tools/wasm'
import { initNostrWasm } from 'nostr-wasm'

// make sure this promise resolves before your app starts calling finalizeEvent or verifyEvent
initNostrWasm().then(setNostrWasm)

// or use 'nostr-wasm/gzipped' or even 'nostr-wasm/headless',
// see https://www.npmjs.com/package/nostr-wasm for options

This may be faster than the pure-JS noble libraries used by default and in nostr-tools/pure.

Using from the browser (if you don't want to use a bundler)

<script src="https://unpkg.com/nostr-tools/lib/nostr.bundle.js"></script>
<script>
  window.NostrTools.generateSecretKey('...') // and so on
</script>

Plumbing

To develop nostr-tools, install just and run just -l to see commands available.

License

This is free and unencumbered software released into the public domain. By submitting patches to this project, you agree to dedicate any and all copyright interest in this software to the public domain.