Concurrency Limit Reached

It is an API error returned when the current one-minute request bucket has no remaining requests.

{
    "is_successful": false,
    "error_code": "concurrency_limit_reached",
    "error_message": "You reached the request concurrency limit, retry after a while. Or feel free to upgrade your current plan—https://dash.screenshotone.com/subscription.",
    "documentation_url": "https://screenshotone.com/docs/errors/concurrency-limit-reached/"
}

Reasons and how to fix

Exceeded request bucket

The most common reason for the “concurrency_limit_reached” error is that you have started all requests allowed by your current plan in the current one-minute bucket.

The limit is not calculated from active render time. For example, if your plan allows 40 requests per minute, you can start up to 40 requests during the current bucket. Those requests can be started in a short burst as long as the bucket has enough remaining requests.

To fix this, you can:

1. Wait and retry: Use the usage endpoint and retry after concurrency.reset.
2. Upgrade your plan: Visit the subscription page to upgrade your plan, which will increase the number of requests you can start per minute.

High Traffic Periods

During high traffic periods, you might use all available requests in the current bucket more quickly.

To fix this, consider:

1. Queueing requests: Queue requests and drain up to concurrency.remaining requests into the API.
2. Retrying after reset: If concurrency.remaining is 0, wait until concurrency.reset before sending more requests.

Bulk workloads

If you process many URLs at once, do not guess a worker count from average render time. Build your worker pool from the usage endpoint instead.

For a starter implementation, an in-process queue with retry/backoff is enough. If you run multiple workers or need durable retries across restarts, use a proper queue such as Redis/BullMQ, SQS, or similar, and let workers drain it according to concurrency.remaining and concurrency.reset.

Reach out to support

If you continue to face issues, please reach out to support@screenshotone.com, and we will assist you as soon as possible.