> ## Documentation Index
> Fetch the complete documentation index at: https://wb-21fd5541-docs-1917.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# API error code 429 - Concurrency limit reached for requests

A 429 error with the message "Concurrency limit reached for requests" means you're sending too many concurrent requests to the Serverless Inference API.

## Why this happens

Serverless Inference enforces concurrency limits to ensure fair usage and service stability. When the number of simultaneous requests from your account exceeds the allowed limit, additional requests are rejected with a 429 status code.

## What you can do

1. **Reduce concurrent requests**
   * Implement request queuing or throttling in your application
   * Use exponential backoff when retrying failed requests

2. **Increase your limits**
   * Review your plan's concurrency limits and upgrade if needed

For more information, see [Usage information and limits](/inference/usage-limits/).

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<Badge stroke shape="pill" color="orange" size="md">[Quotas & Rate Limits](/support/inference/tags/quotas-rate-limits)</Badge>