Rate Limit & Quotas

You can use a certain number of requests per month, defined by your plan.

Once you go over this quota, the API returns a 429 HTTP status code, and you either need to upgrade your plan or wait until the end of the month. We also enforce a minute rate limit on the free plan: up to 10 requests per minute. You can find the quotas of each plan on the pricing page. If you exceed this, the API returns a 429 HTTP status code. You then have to wait until the end of the minute to make more requests. Not every request counts towards your monthly request volume.

Not every request counts
Only successful calls count against your quota. Any error on our side or validation errors (e.g., wrong parameter) will NOT count against your quota or rate limit.

Response Headers

We attach specific headers to tell you your current monthly/minute quota and how much you have remaining in the period.

X-RateLimit-Limit-Quota-Minute: 5
X-RateLimit-Limit-Quota-Month: 100

X-RateLimit-Remaining-Quota-Minute: 3
X-RateLimit-Remaining-Quota-Month: 28

The -Quota-Minute headers are only sent on the free plan; paid plans do not receive them. The minute headers count on the gateway node that answered the request: X-RateLimit-Limit-Quota-Minute shows that node's limit (5), and with our two gateway nodes that makes the 10 requests per minute of the free plan. X-RateLimit-Remaining-Quota-Minute is what is left on that node.

In addition, successful lookup responses (e.g. from /v1/validate) tell you what the request cost and how long it took to process:

Name
X-Cost
Type
integer
Description
The number of requests this call counted against your quota: 1 for a single validation, one per number for a batch request. Requests made with a sandbox API key return X-Cost: 0. Responses from /v1/status never count against your quota and simply carry no X-Cost header.
Name
X-Execution-Time
Type
number
Description
The server-side processing time of the request in milliseconds.

Check out our list of first-party SDKs