Rate limits

Overview

Prefetch API enforces three independent limits:

Global rate limit — per IP address, fixed 1-minute window
Per-key rate limit — per API key, sliding 1-minute window
Per-key concurrency limit — max in-flight requests per key at once

When any limit is exceeded, you receive HTTP 429 Too Many Requests.

Global rate limit

300 requests per minute per IP address, using a fixed 1-minute window. This limit applies before authentication and cannot be configured. It protects the infrastructure from abuse.

Per-key rate limit

Each API key has a rate_limit_rpm (requests per minute) field, enforced with a sliding 60-second window. When a key’s request rate exceeds this value, requests fail with:

{
  "success": false,
  "error": "Rate limit exceeded for this API key",
  "meta": { ... }
}

Contact support or manage your key’s rate limit from the dashboard.

Per-key concurrency limit

Separate from the RPM limit, each key has a maximum number of requests that can be in-flight simultaneously. Exceeding it returns 429 immediately (no queueing). Two headers indicate your current usage:

Header	Description
`X-Concurrency-Limit`	Maximum concurrent requests allowed for this key
`X-Concurrency-Running`	Number of requests currently in-flight

{
  "success": false,
  "error": "Concurrency limit exceeded for this API key",
  "meta": { ... }
}

Handling 429 responses

When you receive a 429, implement exponential backoff before retrying:

async function fetchWithRetry(url, options, maxRetries = 3) {
  for (let attempt = 0; attempt < maxRetries; attempt++) {
    const res = await fetch(url, options);

    if (res.status !== 429) {
      return res;
    }

    const backoffMs = Math.pow(2, attempt) * 1000; // 1s, 2s, 4s
    await new Promise((resolve) => setTimeout(resolve, backoffMs));
  }

  throw new Error("Max retries exceeded");
}

import time
import requests

def fetch_with_retry(url, params, headers, max_retries=3):
    for attempt in range(max_retries):
        r = requests.get(url, params=params, headers=headers)

        if r.status_code != 429:
            return r

        backoff = 2 ** attempt  # 1s, 2s, 4s
        time.sleep(backoff)

    raise Exception("Max retries exceeded")

Tips for staying within limits

Batch wisely — use /enrich instead of separate /brand + /company + /classify calls to reduce request count
Cache responses — most brand/company data is stable; cache it for hours or days
Deduplicate — avoid re-fetching the same domain multiple times in a short window
Queue large jobs — if processing many URLs, space requests out over time rather than sending all at once

Getting started

Core concepts

Overview

Global rate limit

Per-key rate limit

Per-key concurrency limit

Handling 429 responses

Tips for staying within limits

​Overview

​Global rate limit

​Per-key rate limit

​Per-key concurrency limit

​Handling 429 responses

​Tips for staying within limits

Overview

Global rate limit

Per-key rate limit

Per-key concurrency limit

Handling 429 responses

Tips for staying within limits