What is the Valid Email Checker API rate limit?

Default API rate limits per key:

• 60 requests per minute
• 10,000 requests per day (resets at midnight UTC)

When you exceed either, you get an HTTP 429 response with a Retry-After header telling you how many seconds to wait. We also return X-RateLimit-Limit, X-RateLimit-Remaining, and X-RateLimit-Reset headers on every response so you can pace yourself proactively instead of hitting the wall.

Why these limits exist

Two reasons. First, we want every customer's API calls to stay snappy — uncapped concurrency from one account can degrade response times for everyone. Second, our upstream verification engines have their own rate limits, and exceeding them risks getting our verification IPs blocked by mail providers. The 60-per-minute limit gives plenty of headroom for normal real-time signup flows while keeping things stable.

For higher volume

Two paths:

• Use bulk verification instead of looping single-verify calls. For lists larger than a few hundred, the bulk endpoint is faster, cheaper in API calls, and not subject to the per-minute rate limit.
• Request a custom limit on Enterprise. If your real-time use case genuinely needs more than 60/minute or 10K/day, email support@validemailchecker.com with your volume.

How to back off cleanly

If you do hit a 429, the response body includes retry_after_seconds. Wait that long, then retry the same request. Implement this once in your HTTP client wrapper and you do not think about it again. Do not retry every 100ms in a loop — that just keeps you stuck.

{
  "error": "Rate limit exceeded",
  "limit": 60,
  "window": "1 minute",
  "current": 60,
  "retry_after_seconds": 12
}