About This API
I had an old blacklist database that needed cleaning, and I wanted to determine which ASN was announcing each IP in the table. The table had roughly 20,000 rows, and all the public APIs I found were either unreliable, limited (like 50 queries per day), or didn't provide the information I needed. So, I decided to build my own.
This API updates every few hours using routeviews.org's RIB entries and returns the longest prefix match for any given IP, assuming it exists in the database. We then use standard WHOIS lookups to determine a readable AS name for the given ASN.
Terms of Use
Basically, don't get my attention. You can query the API as much as you want, but if your usage breaks something and it gets my attention, I may need to reconsider limits. For now, please keep usage under 100 queries per second. If this API becomes popular, I may adjust or retool it to handle higher demand.
API Endpoint
You can make requests to the following endpoint:
https://ipinfo.141networks.com/Request Format
You can pass the IP address using either a form variable or a JSON body:
Form Variable:
POST https://ipinfo.141networks.com/
Content-Type: application/x-www-form-urlencoded
address=1.1.1.1JSON Body:
POST https://ipinfo.141networks.com/
Content-Type: application/json
{
"address": "1.1.1.1"
}Response Example
{
"status": "success",
"data": {
"prefix": "64.124.176.0/21",
"asn": 6461,
"whois": {
"asn": 6461,
"rir": "ARIN",
"organization": {
"name": "Zayo Bandwidth",
"id": "ZAYOB"
},
"as_details": {
"name": "ZAYO-6461",
"handle": "AS6461",
"registration_date": "1996-04-22",
"updated_date": "2016-06-21"
},
"address": {
"street": "1401 Wynkoop St.",
"city": "Denver",
"state": "CO",
"postal_code": "80202",
"country": "US"
},
"raw": "\n#\n# ARIN WHOIS data and services are subject to the Terms of Use\n# available at: https://www.arin.net/resources/registry/whois/tou/\n#\n# If you see inaccuracies in the results, please report at\n# https://www.arin.net/resources/registry/whois/inaccuracy_reporting/\n#\n# Copyright 1997-2025, American Registry for Internet Numbers, Ltd.\n#\n\n\n#\n# Query terms are ambiguous. The query is assumed to be:\n# \"a AS6461\"\n#\n# Use \"?\" to get help.\n#\n\nASNumber: 6461\nASName: ZAYO-6461\nASHandle: AS6461\nRegDate: 1996-04-22\nUpdated: 2016-06-21 \nRef: https://rdap.arin.net/registry/autnum/6461\n\n\n\nOrgName: Zayo Bandwidth\nOrgId: ZAYOB\nAddress: 1401 Wynkoop St.\nAddress: #500\nCity: Denver\nStateProv: CO\nPostalCode: 80202\nCountry: US\nRegDate: 2007-10-12\nUpdated: 2024-11-25\nRef: https://rdap.arin.net/registry/entity/ZAYOB\n\n\nOrgTechHandle: ZIE-ARIN\nOrgTechName: Zayo IP Engineering\nOrgTechPhone: +1-866-236-2824 \nOrgTechEmail: ipeng@zayo.com\nOrgTechRef: https://rdap.arin.net/registry/entity/ZIE-ARIN\n\nOrgAbuseHandle: ABUSE5675-ARIN\nOrgAbuseName: Abuse\nOrgAbusePhone: +1-866-236-2824 \nOrgAbuseEmail: abuse@zayo.com\nOrgAbuseRef: https://rdap.arin.net/registry/entity/ABUSE5675-ARIN\n\nOrgNOCHandle: ZIE-ARIN\nOrgNOCName: Zayo IP Engineering\nOrgNOCPhone: +1-866-236-2824 \nOrgNOCEmail: ipeng@zayo.com\nOrgNOCRef: https://rdap.arin.net/registry/entity/ZIE-ARIN\n\n\n#\n# ARIN WHOIS data and services are subject to the Terms of Use\n# available at: https://www.arin.net/resources/registry/whois/tou/\n#\n# If you see inaccuracies in the results, please report at\n# https://www.arin.net/resources/registry/whois/inaccuracy_reporting/\n#\n# Copyright 1997-2025, American Registry for Internet Numbers, Ltd.\n#\n\n"
}
}
}Interactive Test
Enter an IP address below to see the API response in real time: