Generate a new API key: API v4

The Website Categorization API uses your existing WhoisXML API key. There is no separate key for this product, and the key you used with the legacy v3 endpoint works with v4. Getting a key and generating a replacement are account functions, described on the existing Generate new API key page and done in your WhoisXML account.

With v4 the key is passed as the apiKey query parameter on every request — see Making requests for where it goes and Error codes for what an invalid key returns. Because the key travels in the URL, keep it out of anything that records full URLs, call the API from your own backend rather than from a browser or a mobile app, and rotate it from your account the moment it has been exposed. When you contact support@whoisxmlapi.com about a failed request, send the X-Request-ID header from the response, never the key.