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 domain, country and ISP, the number of IP addresses, and its IP ranges with the company, country and IP count of each.

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 any autonomous system by its number: organization, country, IP count and IP ranges. The ASN of an IP address comes with every IP API lookup.

The ASN API is part of the Small plan and above.


asn: "AS13335",
organization: "Cloudflare, Inc.",
domain: "cloudflare.com",
country: "US",
isp: "Cloudflare, Inc.",
ip_count: 1543168,
ranges_count: 384

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

Built for developers

Plain REST and JSON, code examples and an OpenAPI spec. Load the spec into your API client to try every endpoint before you write a line of code.

Integration Documentation

The ASN API is part of the Small plan and above.

See pricing

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?