# Limits

Two limits apply when starting a speech-to-text request: a concurrent connection limit and, on the free plan, a credit limit. Both are checked when the request starts - a request that has started always runs to completion.

## Concurrent Connections

Every active speech-to-text session counts as one connection:

- A [Realtime](/speech-to-text/realtime/) or [Turns](/speech-to-text/turns/) WebSocket connection counts while it is open.
- A [Prerecorded](/speech-to-text/prerecorded/) request counts while it is being processed.

A connection stops counting the moment it ends. When you are at the limit, new requests are rejected with status `429`; sessions already in progress are unaffected.

## Credit Limit

On the free plan, usage is capped by a credit limit. As long as you are under the limit you can start any request, and it will run to completion. Once the limit is reached, new requests are rejected with status `402`. Paid plans have no credit limit.