curl -X POST 'https://api.elevenlabs.io/v1/forced-alignment' \
  -H "xi-api-key: $ELEVENLABS_API_KEY" \
  -F 'file=@sample.bin' \
  -F 'text=example-text'

# POST /v1/forced-alignment (ElevenLabs API)
Base URL: https://api.elevenlabs.io
Auth: xi-api-key: <ELEVENLABS_API_KEY>
Last verified: 2026-10-20

> Create Forced Alignment

## Critical Gotchas
* Authentication uses the non-standard `xi-api-key` header, not `Authorization: Bearer`. Sending a Bearer token returns HTTP 401.
* Text-to-speech responses are raw binary audio, not JSON. Write the body to a file (`--output speech.mp3`) rather than parsing it.

## cURL
curl -X POST 'https://api.elevenlabs.io/v1/forced-alignment' \
  -H "xi-api-key: $ELEVENLABS_API_KEY" \
  -F 'file=@sample.bin' \
  -F 'text=example-text'

## Parameters
| Name | In | Type | Required | Description |
| :--- | :--- | :--- | :--- | :--- |
| file | body | string | Yes | The file to align. All major audio formats are supported.... |
| text | body | string | Yes | The text to align with the audio. The input text can be i... |

## Response (200 OK)
{"characters":[{}],"words":[{}]}

---
Need an API key? Get one at https://elevenlabs.io/app/sign-up

POST

POST /v1/forced-alignment — ElevenLabs API

ElevenLabs API

Create Forced Alignment

Base URL: https://api.elevenlabs.io
Auth: xi-api-key: <ELEVENLABS_API_KEY>
Last verified: 2026-10-20 · upstream hash matched

Actions Try in browser→

Agents: curl -H "Accept: text/markdown" this URL
→ 203 tokens · Vary: Accept

Critical gotchas

Authentication uses the non-standard xi-api-key header, not Authorization: Bearer. Sending a Bearer token returns HTTP 401.

Text-to-speech responses are raw binary audio, not JSON. Write the body to a file (--output speech.mp3) rather than parsing it.

cURL

curl -X POST 'https://api.elevenlabs.io/v1/forced-alignment' \  -H "xi-api-key: $ELEVENLABS_API_KEY" \  -F '[email protected]' \  -F 'text=example-text'

Parameters

Name	In	Type	Required	Description
file	body	string	Yes	The file to align. All major audio formats are supported. The file size must be less than 1GB.
text	body	string	Yes	The text to align with the audio. The input text can be in any format, however diarization is not supported at this time.

Response 200 OK

{
  "characters": [
    {
      "end": 0.02,
      "start": 0,
      "text": "H"
    }
  ],
  "words": [
    {
      "end": 1.02,
      "loss": 0.12,
      "start": 0,
      "text": "Hello"
    }
  ],
  "loss": 0
}

Get a free ElevenLabs API key → sponsored

Affiliate link - we may earn a commission, at no extra cost to you.