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

# Usage limits

> Technical quotas and payload limits

Technical limits below are enforced by the API. **Credit balance** and paid access are covered in [Pricing](/guides/pricing).

## Idempotency

| Limit                          | Value                                                          |
| ------------------------------ | -------------------------------------------------------------- |
| `X-Idempotency-Key` max length | 64 characters                                                  |
| Required on                    | Every Open API `POST` — see [Idempotency](/guides/idempotency) |

See [Idempotency](/guides/idempotency).

## TTS and text translation

| Limit                                               | Value        |
| --------------------------------------------------- | ------------ |
| Segments / lines per request (`data` or `segments`) | 50 items max |
| `emoWeight` (TTS)                                   | 0–1          |

## Material upload

| Topic       | Detail                                                                                                                           |
| ----------- | -------------------------------------------------------------------------------------------------------------------------------- |
| Upload path | Direct to CDN via presigned URLs — not through API gateway body size                                                             |
| Multipart   | Use multipart flow for large files; part size guidance in initiate response (S3 minimum typically 5 MB per part except the last) |
| HTTP 413    | Returned when a request body or upload exceeds allowed size                                                                      |

Exact upload request fields: **API reference → Assets - Materials**.

## Rate and concurrency

Per-account rate limits and concurrency caps may apply in production. If you hit throttling, retry with backoff and contact support for higher quotas.

## Related

* [Error codes](/guides/errors) — including `413 Payload Too Large`
* [Pricing](/guides/pricing) — credits and `402`