Your words.
Any language.
Instantly.

Create a narration job

Submit text for async processing. Text is split into parallel chunks and stitched into one WAV file. Returns immediately with a job ID — poll /v1/tts/async/{job_id} for status. Max 100,000 characters per job.

Request body

Response 202 Accepted

{
  "job_id": "888d45c5-1234-...",
  "status": "processing",
  "total_chunks": 4,
  "total_chars": 1240,
  "estimated_seconds": 15,
  "poll_url": "/v1/tts/async/888d45c5-1234-..."
}

Poll job status

Check the status of a narration job. Only the account that created the job may poll it. When status is complete, a presigned S3 URL is included (valid 1 hour). Audio files are purged after 7 days.

Response — processing

{
  "job_id": "888d45c5-...",
  "status": "processing",
  "total_chunks": 4,
  "completed_chunks": 2,
  "failed_chunks": 0,
  "total_chars": 1240,
  "created_at": 1748000000,
  "progress_percent": 50.0
}

Response — complete

{
  "job_id": "888d45c5-...",
  "status": "complete",
  "total_chunks": 4,
  "completed_chunks": 4,
  "failed_chunks": 0,
  "total_chars": 1240,
  "created_at": 1748000000,
  "progress_percent": 100.0,
  "url": "https://s3.amazonaws.com/...",
  "duration_seconds": 184.3
}

Response — failed

{
  "job_id": "888d45c5-...",
  "status": "failed",
  "progress_percent": 75.0,
  "error": "Job failed"
}

Register for an API key

Create a new account. No authentication required. Your API key is emailed immediately. The free_email tier starts with 0 credits — add a payment method via /v1/billing/activate to unlock 125,000 bonus characters.

Request body

Response

{ "message": "Check your email for your API key." }

Check your usage

Monthly usage summary — characters used, quota remaining, daily breakdown, language breakdown. Append ?month=YYYY-MM to query a previous month. Requires authentication.

Create a checkout session

Create a Stripe Checkout session to subscribe to a plan or add a card. Requires authentication. Redirect the user to the returned url. On success, Stripe redirects to /billing/return?session_id=….

Request body

Response

{ "sessionId": "cs_live_...", "url": "https://checkout.stripe.com/..." }

Purchase a top-up pack

Create a one-time Stripe Checkout session to buy additional characters. Requires authentication and an existing billing account (complete a checkout first). Top-up credits never expire.

Request body

Response

{ "sessionId": "cs_live_...", "url": "https://checkout.stripe.com/..." }

Open billing portal

Create a Stripe Customer Portal session for managing subscriptions, payment methods, and invoices. Requires authentication and an existing billing account. Returns to /account on exit.

Response

{ "url": "https://billing.stripe.com/..." }

Retrieve a checkout session

Look up a Stripe Checkout session after redirect — use this on your return page to confirm payment status. Requires authentication.

Query parameters

Response

{
  "id": "cs_live_...",
  "status": "complete",
  "paymentStatus": "paid",
  "customerEmail": "ada@example.com"
}

Activate free account

Linked from the welcome email for free_email accounts. Redirects to a Stripe Checkout setup session to add a payment method and unlock 125,000 bonus characters (no charge). No authentication required — verified by the token in the link.

Query parameters

Response

# 302 redirect → Stripe Checkout setup session URL

Supported languages

Voice styles

Pass either the name or the ID — both are accepted.

Error codes

Rate limits by tier