Notion's Hidden Block Type: Audio

I'm currently working on one of our Notion integrations, Auto Filer, and one of the features it should eventually have is to automatically transcribe voice memos.

This requires processing audio files uploaded to Notion.

I checked Notion's official document but they do not list any audio related block types:

However, Notion clearly supports a block that allows uploading and playing back audio in a page:

In any case, for anyone wanting to use this block type in your application, here is the structure of the audio block:

{
  "object": "block",
  "id": "xxx",
  "parent": {
    "type": "page_id",
    "page_id": "xxx"
  },
  "created_time": "2026-02-19T07:08:00.000Z",
  "last_edited_time": "2026-02-19T07:09:00.000Z",
  "created_by": {
    "object": "user",
    "id": "xxx"
  },
  "last_edited_by": {
    "object": "user",
    "id": "xxx"
  },
  "has_children": false,
  "archived": false,
  "in_trash": false,
  "type": "audio",
  "audio": {
    "caption": [],
    "type": "file",
    "file": {
      "url": "",
      "expiry_time": "2026-02-20T00:01:00.479Z"
    }
  }
}

It's very similar to a file block. Not sure how the caption property works – that wasn't set for the blocks I tested.

It seems also external links are supported, at least according to this GitHub issue:

{
  "object": "block",
  "parent": {
    "type": "page_id",
    "page_id": "40c2fa5c-006c-42f1-8a8f-bbe01ff4be78"
  },
  "created_time": "2024-11-28T07:06:00.000Z",
  "last_edited_time": "2024-11-28T07:08:00.000Z",
  "created_by": {
    "object": "user"
  },
  "last_edited_by": {
    "object": "user"
  },
  "has_children": false,
  "archived": false,
  "in_trash": false,
  "type": "audio",
  "audio": {
    "caption": [],
    "type": "external",
    "external": {
      "url": "https://www.xxxx.com/server/1/40611415.mp3"
    }
  }
}

I hope this provides you a good enough reference for working with the audio object. If not, probably exploring the file block in the Notion API may yield some further direction.