ASN Lookup

Overview

Pass an ASN with or without the leading prefix. The endpoint queries daily-updated registry data to return the registered organization name and numeric identifier. Paid plans include the two-letter country code, registry handle, and the total count of announced IPv4 and IPv6 address ranges.

Live Test ASN Lookup API →

Endpoint

One host, one path per API. The block below shows this call in four languages; every one of them is the same HTTP request. Making requests covers the timeouts, retries and parameter rules that apply to all of them. The SDKs wrap the same call in a typed client.

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curl "https://api.apiverve.com/v1/asnlookup?asn=AS15169" \
  -H "x-api-key: your_api_key_here"

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const res = await fetch('https://api.apiverve.com/v1/asnlookup?asn=AS15169', {
  headers: { 'x-api-key': 'your_api_key_here' },
});

if (!res.ok) throw new Error(`${res.status} ${await res.text()}`);

const { data } = await res.json();
console.log(data);

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import requests

res = requests.get(
    "https://api.apiverve.com/v1/asnlookup?asn=AS15169",
    headers={"x-api-key": "your_api_key_here"},
    timeout=15,
)
res.raise_for_status()

print(res.json()["data"])

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package main

import (
	"fmt"
	"io"
	"net/http"
)

func main() {
	req, _ := http.NewRequest("GET", "https://api.apiverve.com/v1/asnlookup?asn=AS15169", nil)
	req.Header.Set("x-api-key", "your_api_key_here")

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()

	out, _ := io.ReadAll(res.Body)
	fmt.Println(string(out))
}

Replace your_api_key_here with the key from your dashboard. When the inputs arrive as a list rather than one at a time, batch requests run up to 200 of them through this same API in a single call.

Authentication

Send your key in the x-api-key header. That is the only auth step — there is no token exchange and no per-endpoint scope to configure. Authentication covers creating, rotating and revoking keys.

Parameters

Sent in the query string. Premium parameters are accepted on every plan but only take effect on plans that include them.

Response

Every API returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape. Response format covers the envelope, the other output formats and how premium fields are withheld.

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{
  "status": "ok",
  "error": null,
  "data": {
    "asn": "AS15169",
    "simple": "15169",
    "handle": "GOOGLE",
    "description": "Google LLC",
    "country": "US",
    "ipv4RangeCount": 152,
    "ipv6RangeCount": 33,
    "ipv4AddressCount": 1314816
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change. Error handling covers the full status list and which of them are worth retrying.

Use cases

Incident Investigation

When investigating an alert, security teams resolve suspicious IP ownership to determine which hosting provider or telco operates the network.

Bot Traffic Filtering

Flag incoming requests originating from cloud hosting providers rather than consumer internet service providers to block automated scraping.

Signup Fraud Prevention

To stop payment fraud, risk engines compare the cardholder's billing country against the ASN registration country associated with the transaction.

Network Peer Analysis

Network engineers track upstream transit providers by looking up ASNs captured in NetFlow and BGP routing table dumps.

Other ways to use ASN Lookup

Set up ASN Lookup on APIVerve, or reach the same source a different way. Your APIVerve account and credits work on all of them — one key, one balance.

Related

More in Data Lookup: