Free tool · ASN

ASN lookup

Enter an AS number like AS15169 to see who operates the network, where it is registered and which IP ranges it announces.

What is an ASN?

An autonomous system number identifies a network that has its own routing policy on the internet, such as a provider, cloud or large company.

Find the ASN of an IP

Use the IP lookup: it shows the ASN of any address.

Building this into an app? Use the ASN API and its ASN endpoint documentation.

ASN data by API

curl "https://api.ipbase.com/v2/asns?asn=AS13335" -H "apikey: YOUR-API-KEY"

Frequently asked questions

How do I find who owns an ASN?

Enter the number (with or without the AS prefix). The lookup shows the organization, its country and website, and the IP prefixes the network announces.

What are some well-known ASNs?

AS15169 is Google, AS16509 Amazon (AWS), AS13335 Cloudflare, AS8075 Microsoft and AS32934 Meta (Facebook).

IP geolocation API

Get this data in your app

ipbase returns location, ISP, ASN, time zone and security flags (VPN, proxy, Tor, data center) for any IPv4 or IPv6 address, up to 100 addresses per request.

Read the documentation

150 free requests every month. No credit card required.

GET https://api.ipbase.com/v2/info?ip=1.1.1.1

{
  "data": {
    "ip": "1.1.1.1",
    "type": "v4",
    "connection": {
      "asn": 13335,
      "organization": "APNIC and Cloudflare DNS Resolver project",
      "isp": "Cloudflare, Inc",
      "range": "1.1.1.0/24"
    },
    "location": {
      "country": { "alpha2": "AU", "name": "Australia" },
      "zip": "4000"
    },
    "security": { "is_vpn": false, "is_tor": false, "threat_score": 0 }
  }
}

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Example lookups: 8.8.8.8 · 8.8.8.0/24 · AS15169 · example.com · all IPv4 ranges