How we meter
- Text to speech: per character after Unicode normalization.
- Realtime text to speech: per character of appended turn text after Unicode normalization, committed when the turn settles; turns that never produce audio are not billed. See the realtime guide.
- Voice design: per generated preview. When
preview_countis omitted, Breeze generates one preview. - Voice cloning: flat per-job cost.
- List, get, and delete catalog reads: not billed.
Generation concurrency
Each plan includes a maximum number of simultaneous generations. A generation is admitted or running synthesis work. Studio and Developer API jobs share the same per-user pool. Requests over the limit fail fast with429 GENERATION_CONCURRENCY_EXCEEDED and Retry-After.
Sync text to speech, streaming text to speech, async text to speech, voice design, and voice cloning all count toward these limits. Voice design counts each requested preview as one generation.
Where to see your spend
Balance, last 30 days of usage, and per-request charges are on the usage page. For teams or shared accounts, assign a hard credit limit to each API key on the API keys page. Key budgets cap how much of the shared account balance one employee, application, or environment can consume. They do not preallocate credits, and resetting a key budget does not refund the account balance. See Authentication for the exact semantics.Free credits and top-ups
Credits are shared across Studio and the Developer API. Top up on pricing.Plan your usage
Rate limits
Understand concurrent generation limits and retry guidance.
Usage page
Review balance, recent usage, request charges, and credit consumption.
Get usage metering
Query aggregated usage with daily buckets and recent requests programmatically.
Get account balance
Check the current credit balance and recent top-ups before large batch runs.
Text to speech guide
Choose sync, streaming, or async delivery with cost and concurrency in mind.
Errors
Handle insufficient credits, concurrency limits, capacity, and retryable failures.