# Limits – Batch

Learn about rate limiting and usage limits for the Speechmatics Batch API

## Rate limiting and fair usage[​](#rate-limiting-and-fair-usage "Direct link to Rate limiting and fair usage")

Speechmatics Batch SaaS applies rate limiting and fair queueing to provide a consistently high quality of service to all users.

If you make a large number of requests in a short period of time, some of these requests may fail with the response `HTTP 429 - Rate Limited`. To minimize the possibility of encountering rate limiting errors, we recommend that you do not exceed the following rates:

* 10 new jobs per second (POST API calls)
* 50 job status requests per second (GET API calls). Note that Speechmatics recommends using [Notifications](/speech-to-text/batch/notifications.md) for job status updates in production

If you have a large number of concurrent jobs, the most recently submitted jobs may take longer to complete.

While there is generally no limit to the number of jobs you can submit, the following backstop applies to prevent system congestion:

* 20,000 concurrent jobs `HTTP 429 - Max concurrent running jobs exceeded` (POST API calls).

This limit is intended as a safety mechanism and is unlikely to be reached during normal operation. However, it may occur if very slow audio fetching from your servers results in a large build-up of jobs waiting to be processed.

## File size limits[​](#file-size-limits "Direct link to File size limits")

If you submit your media file in the body of the `/jobs` POST request to Speechmatics Batch SaaS, the file must be less than 1 GB in size or the job will be rejected. To process files larger than 1 GB, you can provide the URL of the audio file in the job config as described in the [Fetch URL documentation](/speech-to-text/batch/input.md#fetch-url).

## Custom dictionary limits[​](#custom-dictionary-limits "Direct link to Custom dictionary limits")

If a job's custom dictionary (`additional_vocab`) contains more than 20,000 items, the job is rejected with an `HTTP 400 Bad Request` response and error `Job rejected`. See [Custom dictionary content limits](/speech-to-text/features/custom-dictionary.md#maximum-number-of-custom-dictionary-items) for details.

## Data retention limits[​](#data-retention-limits "Direct link to Data retention limits")

Audio files, transcripts, and configuration data are stored in the Speechmatics Batch SaaS for 7 days. Any request to retrieve a transcript or file more than 7 days after it was processed will receive an HTTP 404 error message and a status of `expired`. You can delete audio or transcripts in advance of this 7 day period - see the [API Reference](/api-ref/batch/delete-a-job.md) for details.