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IP ASN lookup

Look up any IP address to find its ASN, ISP, organization, city and country. Results are cached for 24 hours to respect the free API limit.

IP lookup

Enter an IPv4 address, or leave it blank to look up your own.

Free limit: the lookup API allows about 1,000 requests per day. Results cache in your browser for 24 hours to stay well under it.

Lookup result

Results appear here.

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What an ASN is

An Autonomous System Number identifies a network operator on the internet: ISPs, cloud providers and large companies each hold one or more ASNs. When you see AS15169 you are looking at Google's network, AS16509 is Amazon. ASN lookups reveal who actually routes an IP, which is the first step in network forensics.

Caching and the free limit

ipapi.co's free tier allows roughly 1,000 lookups per day per visitor IP. This tool caches every result in your browser's localStorage for 24 hours, so repeat lookups of the same address cost nothing and the shared quota stays healthy for everyone.

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IP ASN Lookup FAQs

How accurate is IP geolocation?
Country-level accuracy is very good, around 95 percent. City-level is rougher, often landing in the right metro area but not the exact street, and VPNs or corporate networks can place you in a different city entirely.
What is the difference between ISP and organization?
The ISP is the company providing the connection, like Telkomsel or Comcast. The organization is the registered holder of the IP block, which for businesses may be the company itself rather than the ISP.
Can I look up IPv6 addresses?
This tool validates IPv4 only. The underlying API does support IPv6 lookups, but the address format validation here keeps the interface simple and typo-proof.
Why did my lookup fail?
Either the IP was invalid, your connection dropped, or the free daily API quota was exhausted. Cached results still work when the quota is hit, so try an address you looked up before.
Is looking up someone's IP legal?
Looking up publicly routable IP metadata like ASN and rough location is standard network diagnostics, the same data every website logs. It does not reveal a person's name or exact address.
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