nostr-tools

Tools for developing Nostr clients.

Only depends on @scure and @noble packages.

Installation

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

Usage

Generating a private key and a public key

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

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

Creating, signing and verifying events

import {
  validateEvent,
  verifySignature,
  signEvent,
  getEventHash,
  getPublicKey
} from 'nostr-tools'

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

event.id = getEventHash(event)
event.sig = signEvent(event, privateKey)

let ok = validateEvent(event)
let veryOk = verifySignature(event)

Interacting with a relay

import {
  relayInit,
  generatePrivateKey,
  getPublicKey,
  getEventHash,
  signEvent
} from 'nostr-tools'

const relay = relayInit('wss://relay.example.com')
relay.on('connect', () => {
  console.log(`connected to ${relay.url}`)
})
relay.on('error', () => {
  console.log(`failed to connect to ${relay.url}`)
})

await relay.connect()

// let's query for an event that exists
let sub = relay.sub([
  {
    ids: ['d7dd5eb3ab747e16f8d0212d53032ea2a7cadef53837e5a6c66d42849fcb9027']
  }
])
sub.on('event', event => {
  console.log('we got the event we wanted:', event)
})
sub.on('eose', () => {
  sub.unsub()
})

// let's publish a new event while simultaneously monitoring the relay for it
let sk = generatePrivateKey()
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,
  pubkey: pk,
  created_at: Math.floor(Date.now() / 1000),
  tags: [],
  content: 'hello world'
}
event.id = getEventHash(event)
event.sig = signEvent(event, sk)

let pub = relay.publish(event)
pub.on('ok', () => {
  console.log(`${relay.url} has accepted our event`)
})
pub.on('failed', reason => {
  console.log(`failed to publish to ${relay.url}: ${reason}`)
})

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 sub = pool.sub(
  [...relays, 'wss://relay.example3.com'],
  [
    {
      authors: [
        '32e1827635450ebb3c5a7d12c1f8e7b2b514439ac10a67eef3d9fd9c5c68e245'
      ]
    }
  ]
)

sub.on('event', event => {
  // this will only be called once the first time the event is received
  // ...
})

let pubs = pool.publish(relays, newEvent)
pubs.on('ok', () => {
  // this may be called multiple times, once for every relay that accepts the event
  // ...
})

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

let relaysForEvent = pool.seenOn(
  '44e1827635450ebb3c5a7d12c1f8e7b2b514439ac10a67eef3d9fd9c5c68e245'
)
// relaysForEvent will be an array of URLs from relays a given event was seen on

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 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, generatePrivateKey, getPublicKey} from 'nostr-tools'

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

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

let pk = getPublicKey(generatePrivateKey())
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)

Encrypting and decrypting direct messages

import {nip04, getPublicKey, generatePrivateKey} from 'nostr-tools'

// sender
let sk1 = generatePrivateKey()
let pk1 = getPublicKey(sk1)

// receiver
let sk2 = generatePrivateKey()
let pk2 = getPublicKey(sk2)

// on the sender side
let message = 'hello'
let ciphertext = await nip04.encrypt(sk1, pk2, message)

let event = {
  kind: 4,
  pubkey: pk1,
  tags: [['p', pk2]],
  content: ciphertext,
  ...otherProperties
}

sendEvent(event)

// on the receiver side
sub.on('event', event => {
  let sender = event.tags.find(([k, v]) => k === 'p' && v && v !== '')[1]
  pk1 === sender
  let plaintext = await nip04.decrypt(sk2, pk1, event.content)
})

Performing and checking for delegation

import {nip26, getPublicKey, generatePrivateKey} from 'nostr-tools'

// delegator
let sk1 = generatePrivateKey()
let pk1 = getPublicKey(sk1)

// delegatee
let sk2 = generatePrivateKey()
let pk2 = getPublicKey(sk2)

// generate delegation
let delegation = nip26.createDelegation(sk1, {
  pubkey: pk2,
  kind: 1,
  since: Math.round(Date.now() / 1000),
  until: Math.round(Date.now() / 1000) + 60 * 60 * 24 * 30 /* 30 days */
})

// the delegatee uses the delegation when building an event
let event = {
  pubkey: pk2,
  kind: 1,
  created_at: Math.round(Date.now() / 1000),
  content: 'hello from a delegated key',
  tags: [['delegation', delegation.from, delegation.cond, delegation.sig]]
}

// finally any receiver of this event can check for the presence of a valid delegation tag
let delegator = nip26.getDelegator(event)
assert(delegator === pk1) // will be null if there is no delegation tag or if it is invalid

Please consult the tests or the source code for more information that isn't available here.

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.generatePrivateKey('...') // and so on
</script>

Plumbing

1. Install just
2. just -l

License

Public domain.