Function handler reference

Reference documentation for the shape of the function wrapper.

Every Function must export a handler. Handlers contain the logic that the Function infrastructure runs when your document changes trigger the function.

Create a function handler with the sanity blueprints add function command. Every handler receives an object containing context and event parameters. The function does not require a return value.

{
  clientOptions: {
    apiHost: 'https://api.sanity.io',
    projectId: 'abc123',
    dataset: 'production',
    token: '***************'
  }
}

Contains the shape of the event. In the case of document triggers, like publish, the event shape is the document. This will vary based on your schema.

{
  _id: '1234',
  _type: 'article',
  title: 'Functions quick start',
  _createdAt: '2025-04-24T16:26:58.901Z',
  _publishedAt: '2025-04-24T16:26:58.901Z',
}

import { documentEventHandler } from '@sanity/functions'

export const handler = documentEventHandler(async ({ context, event }) => {
  console.log("Context: ", context)
  console.log("Event: ", event)
})

export async function handler({context, event}) {
  console.log("Context: ", context)
  console.log("Event: ", event)
}

When you create a new TypeScript function with sanity blueprint add, you'll be prompted to add types.

If you did not add types as part of the init process, they are available in the @sanity/functions package:

npm install -D @sanity/functions

You can then import and use the documentEventHandler helper to provide type support. See the example TS handler above for implementation details.