An ASN (autonomous system number) identifies an autonomous system: a network with its own routing policy, run by an internet provider, a cloud host or another large organization, and announced as a set of IP prefixes.

ASN lookup API

Q: How is ASN data used?

To segment visitors by network, spot traffic from data centers and hosting providers, and route or block traffic by network.

Q: What does the ASN API return?

The organization behind the network, its country, the number of IP addresses, its registered ranges with their allocation dates, and related domains.

Q: Why do some IP addresses not have ASN data?

Addresses that aren't routed on the public internet, such as the private range 192.168.0.0/16, don't belong to any autonomous system.

Look up the autonomous system behind any IP address: its number, organization, country, IP count and every registered range.


asn: "AS13335",
organization: "Cloudflare, Inc.",
domain: "cloudflare.com",
country: "AU",
isp: "APNIC Research and Development",
ip_count: 512,
ranges_count: 2

See all data fields

ASN lookup API

Every routed IP address belongs to an autonomous system. Its ASN tells you who runs the network.

What the ASN API returns

One request returns the full ASN record as JSON.

See all data fields & code snippets

ASN

Organization

Domain

Country

ISP

IP Count

Ranges Count

Range Details

Tell hosting, business and consumer IPs apart

The ASN shows whether an address belongs to a hosting provider, a business or a consumer ISP, so you can segment users, flag data center traffic and tailor what you show.

Know your users' networks

See which ISPs and networks your users come from, and what that means for their connection speed and data limits.

"We recently implemented ipbase.com and were very impressed with their ASN API. We are using the API to analyze and optimize the user experience of our app users. We had quite a lot of questions as part of the integration phase and their support team never got tired of helping us out."

Wernhard Berger CEO @ Breatheilo

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Frequently asked questions

What is an ASN? How is ASN data used? What does the ASN API return? Why do some IP addresses not have ASN data?