Event

Functions for creating, signing, and verifying Nostr events.

Import

import {
  finalizeEvent,
  verifyEvent,
  getEventHash,
  serializeEvent,
  validateEvent,
  verifiedSymbol,
} from 'nostr-core'

Types

NostrEvent

type NostrEvent = {
  kind: number
  tags: string[][]
  content: string
  created_at: number
  pubkey: string
  id: string
  sig: string
  [verifiedSymbol]?: boolean
}

EventTemplate

type EventTemplate = Pick<NostrEvent, 'kind' | 'tags' | 'content' | 'created_at'>

The minimum fields needed to create an event (before signing).

UnsignedEvent

type UnsignedEvent = Pick<NostrEvent, 'kind' | 'tags' | 'content' | 'created_at' | 'pubkey'>

An event with a pubkey but no id or sig.

VerifiedEvent

interface VerifiedEvent extends NostrEvent {
  [verifiedSymbol]: true
}

An event whose signature has been verified.

finalizeEvent

function finalizeEvent(template: EventTemplate, secretKey: Uint8Array): VerifiedEvent

Signs an event template, adding pubkey, id, and sig fields.

Parameter	Type	Description
template	EventTemplate	Event with kind, tags, content, created_at
secretKey	Uint8Array	32-byte secret key

Returns: VerifiedEvent - the fully signed event.

import { finalizeEvent, generateSecretKey } from 'nostr-core'

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

console.log(event.id)  // 64-char hex
console.log(event.sig) // 128-char hex

verifyEvent

function verifyEvent(event: NostrEvent): event is VerifiedEvent

Verifies an event's hash and schnorr signature. Acts as a TypeScript type guard.

Parameter	Type	Description
event	NostrEvent	Event to verify

Returns: boolean - true if valid, narrowing the type to VerifiedEvent.

Results are cached on the event object via [verifiedSymbol].

if (verifyEvent(event)) {
  // event is now typed as VerifiedEvent
  console.log('Valid event from', event.pubkey)
}

getEventHash

function getEventHash(event: UnsignedEvent): string

Computes the SHA-256 hash of a serialized event (the event id).

Parameter	Type	Description
event	UnsignedEvent	Event with pubkey but no id/sig

Returns: string - 64-character hex hash.

serializeEvent

function serializeEvent(event: UnsignedEvent): string

Serializes an event to NIP-01 canonical JSON format:

[0, "<pubkey>", <created_at>, <kind>, <tags>, "<content>"]

Throws: Error if the event fails validation.

validateEvent

function validateEvent<T>(event: T): event is T & UnsignedEvent

Validates an event's structure. Type guard that checks:

• kind is a number
• content is a string
• created_at is a number
• pubkey is a 64-character hex string
• tags is an array of string arrays

verifiedSymbol

const verifiedSymbol: unique symbol

Symbol used to mark events as verified. Set to true on events that pass verifyEvent() or are created with finalizeEvent().