> ## Documentation Index
> Fetch the complete documentation index at: https://docs.protoface.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Quotas

> Session caps, usage rounding, and credit behavior.

Limits vary by plan. Session responses include the effective limits for that
session.

## Plan limits

| Plan    | Concurrent sessions | Max session duration |
| ------- | ------------------- | -------------------- |
| Free    | 1                   | 2 minutes            |
| Starter | 2                   | 10 minutes           |
| Launch  | 10                  | 20 minutes           |
| Scale   | 50                  | 60 minutes           |

Exceeding a concurrency cap returns `429 quota_exceeded` with
`error.code: "concurrent_sessions"`.

For early capacity planning, estimate the concurrency budget by dividing daily
active users by 250. Rarely, Protoface may rate-limit how quickly new sessions
are created during ramp-up, but that does not reduce the plan's concurrent
session cap.

## Sessions

| Limit              | Default                        |
| ------------------ | ------------------------------ |
| Idle timeout       | 30 seconds without input audio |
| Metadata size      | 8 KB                           |
| Create rate limit  | 10 requests per minute per key |
| Idempotency window | 24 hours                       |

If you send `max_duration_seconds`, Protoface applies the lower of your request
and your plan limit.

## Credits

Usage is rounded up to the nearest minute. One credit equals one rounded-up
session minute. If the account has no usable credits, session creation returns
`402 quota_exceeded` with
`error.code: "insufficient_credit_balance"`.

Free monthly credits do not roll over. Purchased credits roll over without
expiry.

## Metadata keys

`metadata` is customer-owned JSON. Keys beginning with `_avatar.` are managed by
Protoface and are reserved for support-directed use.

## Next

<Columns cols={2}>
  <Card title="Errors" href="/reference/errors" icon="triangle-alert">
    Error responses and retry behavior.
  </Card>

  <Card title="Usage" href="/guides/usage" icon="chart-no-axes-column">
    Inspect usage and credits.
  </Card>
</Columns>