VIES Error

MS_MAX_CONCURRENT_REQ_TIME

Member state time-based rate limit active

What does MS_MAX_CONCURRENT_REQ_TIME mean?

The MS_MAX_CONCURRENT_REQ_TIME error is a variant of the standard rate limit error that specifically relates to time-based throttling. The member state's system tracks requests over a time window, and you've exceeded the allowed rate.

This is subtly different from MS_MAX_CONCURRENT_REQ: - MS_MAX_CONCURRENT_REQ: Concurrent requests at this moment exceed limits - MS_MAX_CONCURRENT_REQ_TIME: Requests over a time period exceed limits

When does this error occur?

  • When you've made too many requests to a specific country within a time window
  • During sustained high-volume operations against one member state
  • When your request rate exceeds the country's sustained throughput limit

Time windows

The exact time windows aren't published, but based on behavior they appear to be: - Short window: Requests per second limit - Medium window: Requests per minute limit - Long window: Requests per hour limit

Hitting any of these thresholds can trigger the error.

Slow down your request rate

This error indicates you're making too many requests too quickly. Unlike instant concurrent limits, time-based limits require you to reduce your overall throughput, not just wait a moment.

How to handle MS_MAX_CONCURRENT_REQ_TIME

1. Use a high-volume VAT validation service

VatDB manages request rates across all data sources automatically. Our infrastructure handles thousands of validations per minute without hitting rate limits by connecting to multiple official EU and national databases. Use webhooks to receive results asynchronously without rate limit concerns.

2. Implement proper rate limiting

Don't just retry. Reduce your request rate. Limit to 1 request per second per country and add delays between requests.

3. Spread requests across time

If you have bulk validations, spread them out rather than running them all at once.

4. Use queuing

Queue requests and process them at a sustainable rate instead of attempting immediate validation.

High-volume VAT validation without rate limits

VatDB manages request rates across multiple official EU and national databases automatically. Our infrastructure handles thousands of validations per minute without hitting rate limits. Use webhooks to receive results asynchronously. Scale your validation without throttling headaches.

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Frequently Asked Questions

What's the difference between MS_MAX_CONCURRENT_REQ and MS_MAX_CONCURRENT_REQ_TIME?
MS_MAX_CONCURRENT_REQ is about simultaneous requests right now. MS_MAX_CONCURRENT_REQ_TIME is about total requests over a time period. You can hit the time-based limit even with sequential requests if your rate is too high.
How long should I wait before retrying?
Longer than for standard rate limits. Wait at least 10 to 30 seconds, then resume at a slower rate. The time window needs to expire before your request count resets.
Can I avoid this by spreading requests across countries?
Yes, time-based limits are per-country. Validating numbers from different countries in parallel is fine. Just avoid hammering one country repeatedly.
How does VatDB handle high-volume validation?
VatDB distributes requests intelligently across multiple official sources and manages per-country rate limits automatically. We process high volumes by using our infrastructure's capacity rather than maxing out VIES limits. Webhooks let you handle results asynchronously.