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: 10
X-RateLimit-Limit-Quota-Month: 300

X-RateLimit-Remaining-Quota-Minute: 5
X-RateLimit-Remaining-Quota-Month: 199

The -Quota-Minute headers are only sent on the free plan; paid plans do not receive them.

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