apicheats.dev elevenlabs/llms.txt Raw .md
POST

/v1/forced-alignment

ElevenLabs API

Create Forced Alignment

Base URL
https://api.elevenlabs.io
Auth
xi-api-key: <ELEVENLABS_API_KEY>
Last verified
2026-09-03 · upstream hash matched
Actions
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 'file=@sample.bin' \  -F 'text=string'
Get a free ElevenLabs API key → sponsored

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
}