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Speech-to-Text API · billing diagnostic

Why is your speech-to-text API bill high?

Direct answer

A speech-to-text API bill almost always climbs from a metered unit crossing its free allowance — most often audio transcribed. Check the drivers below in order (biggest lever first), compare each against your plan's free tier in the vendor console, and look for a sudden usage change. These are the common causes, not a reading of your specific invoice.

The usual cost drivers — check in this order

Every provider in this category meters these. Past the free allowance, each is billed per unit — so a spike in any one moves the bill.

  • ·audio transcribed — 100 hours ≈ 200 half-hour calls; streaming vendors may also bill connection time. This is a metered unit: past the free allowance you pay per audio transcribed.

Tool-specific cliffs (from verified pricing risks)

Documented ways each tool's bill jumps — verify against your own plan and usage.

  • ·Deepgram: Legacy models (Nova-2, Enhanced, Base) no longer have published prices
  • ·AssemblyAI: Streaming bills on WebSocket connection time, not audio sent — an idle open socket still accrues cost
  • ·OpenAI Transcription: Per-minute figures are OpenAI's own estimates; actual billing is per audio token and varies with audio density
  • ·Groq (Whisper): 10-second minimum per request — many short clips inflate cost
  • ·Google Cloud Speech-to-Text: V1 rounds each request up to 15-second increments; multichannel audio bills per channel
  • ·Cartesia (STT): No published overage — exceeding a tier means the next tier up

Where to check in your vendor console

  • ·Open the usage/billing dashboard and find the line item that grew — it names the metered unit.
  • ·Compare current usage to your plan's free allowance (the free-tier caps on that tool's pricing page).
  • ·Look for a step change vs a gradual climb: a step usually means a plan change, a new feature, or crossing a free-tier cliff.
  • ·Check egress/bandwidth and idle/always-on resources separately — they're common surprises the headline price hides.

These are the common causes for this category, not a diagnosis of your specific bill. Confirm in your vendor's usage dashboard, and contact vendor support if the numbers still don't add up. Prices and free tiers change — check the dated sources below.

FAQ

What usually makes a speech-to-text API bill spike suddenly?

A sudden jump is most often a metered unit (audio transcribed) crossing the free-tier cap, a plan change, or a new feature — a step change rather than a gradual climb.

Can StackSays tell me my exact bill cause?

No — only your vendor's usage dashboard shows your actual usage. This page lists the likely causes and where to verify each; it never claims to read your invoice.

Official sources

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