Find the organization that operates any ASN.
ASN Lookup resolves any Autonomous System Number to its registered organization name and numeric identifier. Paid plans add the registry handle, country code, and announced IP range statistics.
Try it — live request, no key required
No key required to try it. Get a key to use it in your app.
{
"status": "ok",
"error": null,
"data": {
"asn": "AS15169",
"simple": "15169",
"handle": "GOOGLE",
"description": "Google LLC",
"country": "US",
"ipv4RangeCount": 153,
"ipv6RangeCount": 33,
"ipv4AddressCount": 1379072
}
}
About the ASN Lookup API
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.
What people use it for
- 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.
Ways to call it
One endpoint, many ways in — REST with JSON, XML, YAML and CSV, plus GraphQL and an MCP interface for AI agents.
- JSON
- Default REST response
- XML
- Markup format
- YAML
- Human-readable
- CSV
- Tabular export
- GraphQL
- Query language
- MCP
- For AI agents
Other ways to use ASN Lookup
Same data, same APIVerve account, same credit balance — one key works on all of them.
Is it cheap enough to check an ASN for every suspicious connection?
Do I get the country code and handle on the Free plan?
Do I need to include the 'AS' prefix when submitting a query?
How frequently is the ASN data refreshed?
Can I use ASN Lookup data in a commercial security product?
Request parameters — GET /v1/asnlookup
Sent in the query string. Premium parameters are accepted on every plan but only take effect on plans that include them. Anything not listed here is dropped rather than passed through.
Required
| Parameter | Type | Example | Description |
|---|---|---|---|
asnRequired | string | AS15169 | The ASN you want to get information about |
curl "https://api.apiverve.com/v1/asnlookup?asn=AS15169" \
-H "x-api-key: YOUR_API_KEY"Authentication
Send your key in the x-api-key header. That is the only auth step — no token exchange, and no per-endpoint scope to configure.
| Header | When | Value |
|---|---|---|
x-api-keyRequired | Every request | Your API key. Header names are case-insensitive, so X-API-Key is the same header. |
AuthorizationAlternate | Instead of the above | Bearer <key> — for clients that only expose bearer auth. Resolves to the same account and the same billing. |
A 401 means the key is missing, invalid or expired. A 403 means the key is valid but not permitted here — blocked by a key restriction or an IP allow-list. Running out of credits is a 429.
Response — GET /v1/asnlookup
Every APIVerve endpoint returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape.
{
"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.
| Field | Type | Example | Description |
|---|---|---|---|
asn | string | "AS15169" | Full ASN notation (e.g., AS15169 for Google) |
simple | string | "15169" | Numeric ASN without AS prefix (e.g., 15169) |
handlePremium | string | "GOOGLE" | Registry handle or short identifier for the AS |
description | string | "Google LLC" | Organization name or description associated with ASN |
countryPremium | string | "US" | Two-letter country code where the ASN is registered |
ipv4RangeCountPremium | number | 152 | Number of IPv4 address ranges this AS announces |
ipv6RangeCountPremium | number | 33 | Number of IPv6 address ranges this AS announces |
ipv4AddressCountPremium | number | 1314816 | Total IPv4 addresses across those ranges |
Response headers
Every response carries your balance, so your own code always knows where it stands without polling anything. All four are exposed to browsers through CORS.
| Header | What it carries |
|---|---|
x-api-remaining-credits | Credits left in the current cycle |
x-api-credits-used | Credits spent in the current cycle |
x-api-max-credits | The allowance for the cycle |
x-api-version | Version of the endpoint that answered |
Errors
Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change.
| Status | Meaning | What to do |
|---|---|---|
400 | Input was rejected | Read error; it names the parameter that has to change. |
401 | Key missing or invalid | Check the header name and the key value. |
403 | Key valid, but not permitted here | A key restriction or an IP allow-list — never a bad key. |
429 | Rate limited, or out of credits | Read error to tell them apart, then back off or top up. |
What a call costs — 4 credits per call
Credits are shared across every APIVerve API — one balance, one key, one bill. Failed requests never count against it, so a rejected input costs nothing.
| Plan | Per month | Credits | ASN Lookup calls | Per 1,000 calls |
|---|---|---|---|---|
| Free | Free | 200 | 50 | Free |
| Starter | $29.99 | 200,000 | 50,000 | $0.60 |
| Pro | $99.99 | 1,000,000 | 250,000 | $0.40 |
| Mega | $299.99 | 4,000,000 | 1,000,000 | $0.30 |
Calls are what the credits buy at this API's rate — spend them here, on any of the other APIs, or across both. Nothing is reserved per endpoint.
Call it from cURL — GET /v1/asnlookup
No SDK to install — this is a plain HTTPS call to /v1/asnlookup with your key in the x-api-key header. Swap in a real key and it runs as-is.
curl "https://api.apiverve.com/v1/asnlookup" \
-H "x-api-key: YOUR_API_KEY"Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from Node.js — GET /v1/asnlookup
Install the Node.js SDK, then call the ASN Lookup API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.
npm install @apiverve/asnlookupconst res = await fetch("https://api.apiverve.com/v1/asnlookup", {
headers: { "x-api-key": "YOUR_API_KEY" },
});
const { data } = await res.json();
console.log(data);Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from Python — GET /v1/asnlookup
Install the Python SDK, then call the ASN Lookup API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.
pip install apiverve-asnlookupimport requests
res = requests.get(
"https://api.apiverve.com/v1/asnlookup",
headers={"x-api-key": "YOUR_API_KEY"},
)
print(res.json()["data"])Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from C# / .NET — GET /v1/asnlookup
Install the C# / .NET SDK, then call the ASN Lookup API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.
dotnet add package APIVerve.API.ASNLookupusing var client = new HttpClient();
client.DefaultRequestHeaders.Add("x-api-key", "YOUR_API_KEY");
var json = await client.GetStringAsync("https://api.apiverve.com/v1/asnlookup");
Console.WriteLine(json);Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from Go — GET /v1/asnlookup
No SDK to install — this is a plain HTTPS call to /v1/asnlookup with your key in the x-api-key header. Swap in a real key and it runs as-is.
req, _ := http.NewRequest("GET", "https://api.apiverve.com/v1/asnlookup", nil)
req.Header.Set("x-api-key", "YOUR_API_KEY")
res, _ := http.DefaultClient.Do(req)
defer res.Body.Close()
body, _ := io.ReadAll(res.Body)
fmt.Println(string(body))Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from PHP — GET /v1/asnlookup
No SDK to install — this is a plain HTTPS call to /v1/asnlookup with your key in the x-api-key header. Swap in a real key and it runs as-is.
$ch = curl_init("https://api.apiverve.com/v1/asnlookup");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-api-key: YOUR_API_KEY"]);
$response = curl_exec($ch);
echo $response;Resources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Call it from Ruby — GET /v1/asnlookup
No SDK to install — this is a plain HTTPS call to /v1/asnlookup with your key in the x-api-key header. Swap in a real key and it runs as-is.
require "net/http"
uri = URI("https://api.apiverve.com/v1/asnlookup")
req = Net::HTTP::Get.new(uri)
req["x-api-key"] = "YOUR_API_KEY"
res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |h| h.request(req) }
puts res.bodyResources
Also published for
Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.
Zero-code embed — one snippet, no backend
Drop an interactive ASN Lookup form onto any page. The widget calls the API for you, so no key ever appears in your markup and there is nothing to deploy.
Changelog — ASN Lookup API
Every change to this endpoint, newest first. Breaking changes ship as a new version and the previous one keeps serving — response fields are added, never removed or retyped in place, so an integration written against v1 keeps working.
Entries are picked up from dated catalog snapshots, so the first one appears after the next snapshot that moves something. A period where nothing changed produces no entry — silence is a valid changelog for the ASN Lookup API.
Data Lookup
- ASN Lookup
- Bible
- Country Calling Code
- Dictionary
- Dog Breeds
- Emoji Lookup
- Gender Detector
- Gravatar Lookup
- IP Demographics
- Lottery Numbers
- Nobel Prizes
- Open Source Licenses
- Thesaurus
- Timezone Lookup
- Unicode Character Lookup
- World Time
- ZIP Demographics