Grok STT API

Introduction

What it returns

The transcript as text on the task result, plus output.transcript: the detected language and language code, the audio length in seconds, and every word with its start and end time in seconds. With multichannel on, output.transcript.channels holds the same for each channel. Speaker labels are not included.

Sending audio

audio_url takes an uploaded MP3 or WAV, or a public URL to MP3, WAV, M4A, FLAC, OGG, Opus, AAC, MP4 or MKV, from 1 second to 2 hours. The URL has to answer with the audio itself. Raw audio without a file header (PCM, μ-law, A-law) is not accepted.

Language and numbers

Leave language empty and the language is detected; speech in any of the 25 supported languages is transcribed either way. text_normalization needs language.

Key terms and filler words

keyterms takes up to 100 terms of up to 50 characters, one per row. In our test "Xandrelle" and "Qorvessa" came back as "Xandrel" and "Corvessa" without them and exactly right with them. filler_words keeps um and uh, which are removed by default.

Several channels

Turn on multichannel for recordings with each speaker on their own channel. Each channel is transcribed separately and returned on its own line, in channel order. Leave it off only when every channel carries the same sound: in our tests a stereo file with a different speaker on each side came back with one of the two speakers missing.

Request parameters

Pricing

Prices are in credits, the same credits you use on the website (1 credit = $0.01). The hold is taken when the task is accepted and settled to the actual charge when it finishes; failed tasks are refunded.

For an exact number before you run, send the same body to POST /jobs/quote.

API quick start

Call the Grok STT API in three steps

1. Create an API key. Sign in to PopNow and create a key in the API console. Keys start with sk-popnow- and use the same credits as the website.
2. Send the request. POST /jobs/createTask with model xai/grok-stt/speech-to-text and an input object that follows the parameter table. The response returns a task ID straight away.
3. Get the result. Poll GET /jobs/recordInfo with the task ID, or pass a callBackUrl and we post the result to it. Download the output links when the task succeeds.

# 1. Create the task. Keep the Idempotency-Key if you retry after a network error.
export IDEMPOTENCY_KEY="$(uuidgen)"
curl -X POST https://api.popnow.ai/api/v1/jobs/createTask \
  -H "Authorization: Bearer $POPNOW_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $IDEMPOTENCY_KEY" \
  -d '{
  "model": "xai/grok-stt/speech-to-text",
  "input": {
    "audio_url": "https://media.popnow.ai/shortfilm/voices/Aoede-46e4c427.mp3"
  }
}'

# 2. Copy data.taskId from the response, then poll until state is succeeded, failed, canceled or expired.
TASK_ID="TASK_ID_FROM_RESPONSE"
curl "https://api.popnow.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
  -H "Authorization: Bearer $POPNOW_API_KEY"

Replace the prompt and any links with your own. The API tab has the response, polling and callback reference.

Grok STT API questions

All Grok models

HeartMuLa Transcribe is tuned for sung lyrics over music; Grok handles spoken audio.

• Grok STT APITranscripts with word timings in 25 languagesFrom 0.01 credits per second
• Grok TTS API71 voices across 20 languages with speech tagsFrom 3 credits per 1,000 characters

Other audio APIs

• HeartMuLa Transcribe APILyrics pulled from sung vocals, in many languagesFrom 8 credits per run

More about Grok STT

Try it

Grok STT AI Speech to Text onlineCreate audio with Grok STT in PopNow

Docs

Grok STT model ID and input schema in the API docsPopNow API quickstart: your first request in five minutesWebhooks: get Grok STT results without polling