IP ASN Lookup — resolve ASN and RDAP details

IP ASN Lookup API

What it does

IP ASN Lookup resolves an IP address to the network and registry details exposed by RDAP. Send an ip value and get back the IP, the ASN when available, the ASN registry, the network CIDR, the network name, the ASN description, and the ASN country code.

Use it when you need to identify who operates an address block, map traffic to an upstream network, or enrich security and network telemetry with ownership data. The response is intentionally compact, so it fits neatly into routing, abuse-checking, asset inventory, and analytics workflows.

Because the lookup is based on RDAP, results reflect registry data rather than guessed location or ISP information. That makes it useful for IP reputation checks, incident response triage, and backend tools that need a reliable ASN reference before making a decision.

If the registry does not expose a value, the corresponding field can be null, so you can handle partial results without guessing.

What you'll get back

Returns a JSON object with these top-level fields: ip is the IP address looked up, and asn, asn_registry, network_cidr, network_name, asn_description, and asn_country_code are nullable strings with the matching network/ASN information when available.

{
  "ip": "8.8.8.8",
  "asn": "15169",
  "asn_registry": "arin",
  "network_cidr": "8.8.8.0/24",
  "network_name": "GOOGLE",
  "asn_description": "Google LLC",
  "asn_country_code": "US"
}

About this endpoint

What it does

Looks up RDAP-based ASN and network details for the IP address provided in the query string. The response returns the queried ip plus associated ASN, registry, network CIDR, network name, ASN description, and ASN country code fields when available.

Query Parameter(s)

Attribute	Type	Mandatory	Description
ip	String	Yes	IP address to look up.

Response

Returns a JSON object with these top-level string fields: ip, asn, asn_registry, network_cidr, network_name, asn_description, and asn_country_code. The optional fields are nullable in the schema, so they may be null when the RDAP lookup does not provide a value.

Parameter	Type	Mandatory	Description
ip	String	No	The IP address that was looked up.
asn	String	No	The ASN associated with the IP, or `null` if unavailable.
asn_registry	String	No	The registry associated with the ASN, or `null` if unavailable.
network_cidr	String	No	The network CIDR for the IP, or `null` if unavailable.
network_name	String	No	The network name, or `null` if unavailable.
asn_description	String	No	The ASN description, or `null` if unavailable.
asn_country_code	String	No	The ASN country code, or `null` if unavailable.

Query parameters

Name

Type

Description

ipREQUIRED

string

—

IP ASN Lookup API

What it does

Quickstart

What you'll get back

About this endpoint

What it does

Query Parameter(s)

Response

Query parameters

Errors any endpoint can return