Googlebot IP verification is the process of confirming that a web crawl request genuinely originates from Google rather than from a third party spoofing the Googlebot user agent string. Because user agents can be faked trivially, the authoritative verification method recommended by Google is a reverse DNS lookup followed by a forward DNS confirmation: the IP address of the incoming request is resolved to a hostname, which should end in googlebot.com or google.com, and that hostname is then resolved back to an IP address to confirm it matches the original requester. Google publishes its current list of crawler IP ranges in JSON format at a well-known URL, which can also be used for allowlist-based verification. Accurate Googlebot identification is important for server-side personalisation logic, rate limiting rules, and security systems, as impersonating Googlebot to bypass controls is a known attack vector. Google also operates special-user-agent crawlers such as APIs-Google for other services.