Domain search API

Last updated November 8, 2026

Show your users whether a domain name is available and what it costs at CertPing, from your own website or app. The API is read-only: it never registers or reserves a name.

Getting started

Create a CertPing account for your company.
In the CertPing app, open Domains, then Developer API keys, and create a key. Copy the key when it is shown: it starts with cpk_live_ and is shown only once.
Optional: when you create the key, list the IP addresses your servers call from in its IP allowlist. We then refuse the key from any other address, so a leaked key cannot be used elsewhere.
Call the endpoints below from your servers, never a browser.

Authentication

Send the key in the Authorization header of every request. Keep it on your servers: anyone holding it spends your quota.

Authorization: Bearer cpk_live_...

Every endpoint is under https://dns-api.certping.com/api/v1/domains/token-api.

GET /domains/availability

Whether names can be registered, with what each costs to register, renew and transfer in.

domain: A full name such as example.com. Checks that one name. Takes precedence over name.
name: A name without an ending, such as example. Checks it under the popular endings we sell.

curl -H "Authorization: Bearer $CERTPING_API_KEY" \
  "https://dns-api.certping.com/api/v1/domains/token-api/domains/availability?domain=example.com"

{
  "query": "example.com",
  "currency": "USD",
  "results": [
    {
      "domain": "example.com",
      "tld": "com",
      "availability": "AVAILABLE",
      "purchasable": true,
      "premium": false,
      "registrationPrice": 13.00,
      "renewalPrice": 14.95,
      "transferPrice": 13.40,
      "registrationTerms": [
        { "years": 1, "total": 13.00 },
        { "years": 2, "total": 27.95 }
      ]
    }
  ]
}

GET /domains/prices

Our one-year prices for the popular endings, and the shortest term each is sold for.

curl -H "Authorization: Bearer $CERTPING_API_KEY" \
  "https://dns-api.certping.com/api/v1/domains/token-api/domains/prices"

{
  "currency": "USD",
  "prices": [
    {
      "tld": "com",
      "registrationPrice": 13.00,
      "renewalPrice": 14.95,
      "transferPrice": 13.40,
      "registrationTerm": { "years": 1, "total": 13.00 },
      "renewalTerm": { "years": 1, "total": 14.95 }
    }
  ]
}

Reading the results

availability is AVAILABLE, TAKEN or UNKNOWN. UNKNOWN means the registry could not be asked just then; it is never a guess either way. When a registry was busy, the response also carries retryAfterSeconds: ask again after it.
Prices are in the response’s currency, as numbers with two decimals. A price is null where we do not sell that term, such as one year of .ai, or where it cannot be quoted right now; never show a null price as free.
purchasable is false for a name that cannot be bought online, such as some premium names.
Some endings, such as .ai, are sold for two years at least: registrationTerms lists each term with its total.
Answers can be up to a minute old. New fields may be added to any response, so ignore fields you do not know.

Rate limits

Your organization may make 60 availability checks a minute across all its keys. A check counts even when the registrar then fails to answer; a malformed name or an ending we do not sell does not. A successful or quota-refused availability answer carries RateLimit-Limit and RateLimit-Remaining for those checks, and RateLimit-Reset: the window’s length in seconds, or on a refusal the seconds until it ends. Other answers may carry RateLimit-Limit and RateLimit-Remaining for the key’s overall request rate instead. A refused request carries Retry-After, the seconds to wait.

Prices change rarely: fetch /domains/prices once and keep it for a few minutes rather than on every page view. If you need a higher limit, contact us.

Errors

An error answers with a JSON body whose message says what went wrong.

400: The name is not a valid domain name, or we do not sell its ending. A malformed name or an ending we do not sell costs no quota.
401: The key is missing, unknown, revoked or expired.
403: The key lacks the Domain search permission, or is used from an address outside its IP allowlist.
423: Domain search is switched off for maintenance. Try again later.
429: A rate limit or your organization's availability quota is spent. Wait the seconds in Retry-After.
500: Something failed on our side. Try again in a moment.
502: The registrar answered with an error. Try again shortly; contact us if it lasts.
503: The registrar is busy or prices are briefly unavailable. Wait the seconds in Retry-After, or a few seconds.
504: The registrar did not answer in time. Try again in a moment.

OpenAPI

The OpenAPI description describes both endpoints for code generators and API tools.