Explore AS metadata interactively at Lens by ipverse — search IP addresses, prefixes, and autonomous systems without downloading anything.
A comprehensive dataset of autonomous system metadata for all assigned ASNs (autonomous system numbers). Includes handle, organization name, and country code sourced from regional internet registries (RIR). Updated automatically when source data changes (checked daily).
Perfect for offline lookups, network analysis, threat intelligence, or any project where you need to map ASNs to organizations—no API rate limits, no external dependencies.
- 2026-03-04: Added
metadata.lastModifiedandstats.prefixesLastModifiedchange-tracking timestamps; all timestamp fields now use date-only format (yyyy-MM-dd) to reduce file size - 2026-02-08: Added
category(e.g.isp,hosting,government_admin) andnetworkRole(e.g.tier1_transit,stub) fields to AS metadata - 2026-01-27: Added
providerAsnsfield with list of upstream transit provider ASNs - 2026-01-18: Breaking change: Replaced
upstreams/downstreamswithproviders/customers/peersto accurately distinguish transit relationships from peering. Addeddegreeandreachfields. - 2026-01-08: Added
registeredfield (RIR registration date),statssection (prefix and connectivity statistics), and movedlastAnnouncedto top level. - 2026-01-03: Repository renamed to
as-metadata, CSV format changed to 4 columns (added country-code), JSON format added. - 2025-08-03: Removed opinionated handle cleanup and removed quotes around descriptions to improve RFC4180 compliance
- 2023-09-03: Removed PEM certificates from description field
JSON (~55-60 MB) and CSV (~6 MB)
JSON format:
[
{
"asn": 4711,
"metadata": {
"handle": "INTEC",
"description": "INTEC Inc.",
"countryCode": "JP",
"country": "Japan",
"origin": "authoritative",
"category": "business",
"networkRole": "stub",
"registered": "1997-03-14",
"lastModified": "2026-03-01"
},
"stats": {
"ipv4": {
"prefixes": 12,
"prefixesAggregated": 8,
"largestPrefix": 20
},
"ipv6": {
"prefixes": 3,
"prefixesAggregated": 2,
"largestPrefix": 32
},
"connectivity": {
"providers": 2,
"providerAsns": [174, 3356],
"customers": 5,
"peers": 3,
"degree": 10,
"reach": 12
},
"prefixesLastModified": "2026-03-04"
},
"lastAnnounced": "2026-01-04"
},
{
"asn": 4712,
"metadata": {
"handle": "JT-NET",
"description": "JAPAN TOBACCO INC.",
"countryCode": "JP",
"country": "Japan",
"origin": "authoritative",
"category": null,
"networkRole": null,
"registered": "1997-03-14",
"lastModified": null
},
"stats": null,
"lastAnnounced": null
}
]CSV format:
asn,handle,description,country-code0,IANA-RSVD-0,Internet Assigned Numbers Authority,US1,LVLT-1,Level 3 Parent LLC,US2,UDEL-DCN,University of Delaware,US3,MIT-GATEWAYS,Massachusetts Institute of Technology,US4,ISI-AS,University of Southern California,US5,SYMBOLICS,WFA Group LLC,US6,BULL-HN,ATOS IT Solutions and Services Inc.,US7,DSTL,The Defence Science and Technology Laboratory,GB
.
.
.| Field | Description |
|---|---|
asn | Autonomous System Number |
handle | Registry handle/identifier |
description | Organization name or description |
country-code | ISO 3166-1 alpha-2 country code (XX if unknown) |
| Field | Description |
|---|---|
asn | Autonomous System Number |
metadata.handle | Registry handle/identifier |
metadata.description | Organization name or description |
metadata.countryCode | ISO 3166-1 alpha-2 country code |
metadata.country | Full country name |
metadata.origin | Metadata source (see origin values) |
metadata.category | AS classification; null if unclassified (see AS category and network role) |
metadata.networkRole | Network role; null if unknown (see AS category and network role) |
metadata.registered | RIR registration date (yyyy-MM-dd); null for inferred ASNs |
metadata.lastModified | Date (yyyy-MM-dd) when any metadata field last changed (includes RIR data, category, network role, etc.); null if never announced |
stats | Prefix and connectivity statistics; null for ASNs without route collector data |
stats.ipv4.prefixes | Number of IPv4 prefixes announced |
stats.ipv4.prefixesAggregated | Number of IPv4 prefixes after aggregation |
stats.ipv4.largestPrefix | Largest IPv4 prefix announced (e.g. /13 — smaller number = larger block) |
stats.ipv6.prefixes | Number of IPv6 prefixes announced |
stats.ipv6.prefixesAggregated | Number of IPv6 prefixes after aggregation |
stats.ipv6.largestPrefix | Largest IPv6 prefix announced (e.g. /29 — smaller number = larger block) |
stats.connectivity.providers | Number of transit provider ASNs |
stats.connectivity.providerAsns | List of transit provider ASNs (enables upstream quality analysis) |
stats.connectivity.customers | Number of transit customer ASNs |
stats.connectivity.peers | Number of settlement-free peer ASNs |
stats.connectivity.degree | Total unique neighbor ASNs (providers + customers + peers) |
stats.connectivity.reach | Customer cone size (ASNs reachable via customer relationships) |
stats.prefixesLastModified | Date (yyyy-MM-dd) when announced prefixes last changed; only present when stats is non-null |
lastAnnounced | Date (yyyy-MM-dd) when AS was last seen announcing prefixes; null if never seen |
| Value | Description |
|---|---|
authoritative | From authoritative source |
inferred | Inferred from routing information; may be inaccurate |
overlaid | Metadata overlay from as-overlay applied |
none | No metadata available |
Classifies the primary function of an autonomous system.
| Value | Description |
|---|---|
isp | Internet service provider (broadband, DSL, cable, fiber, mobile) |
hosting | Hosting, cloud, or content provider |
business | Enterprise or non-profit organization |
education_research | Educational or research institution |
government_admin | Government entity or public administration |
null when unclassified.
Categorization is based on multiple signals and reflects the AS's primary function. It won't always be correct — many networks defy clean categorization (e.g. an ISP that also runs a hosting business, or a university with its own transit infrastructure). Take it as a useful default, not gospel. An overlay mechanism for user-supplied corrections may be added in the future.
Describes the connectivity role of an autonomous system based on BGP topology.
| Value | Description |
|---|---|
tier1_transit | Tier 1 transit provider with settlement-free global reach |
major_transit | Major transit provider |
midsize_transit | Mid-size transit provider |
access_provider | Access or eyeball network |
content_network | Content delivery network |
stub | Stub AS with no transit customers |
null when unknown.
Role assignment is based on BGP connectivity metrics with opinionated thresholds. Reasonable people may disagree on where exactly to draw the line between "major" and "mid-size" transit, or when a network stops being a stub.
Download the data directly:
JSON:
curl -O https://raw.githubusercontent.com/ipverse/as-metadata/master/as.jsonCSV:
curl -O https://raw.githubusercontent.com/ipverse/as-metadata/master/as.csvOr just clone the repo if that's your thing.
Quick example (Python):
importjsonwithopen('as.json') asf:
data= {entry['asn']: entryforentryinjson.load(f)}
print(data[4711]['metadata']['description']) # INTEC Inc.- Figure out who owns an ASN
- Enrich your IP intelligence tools
- Threat hunting and security research
- BGP analysis and network research
- Building dashboards or monitoring tools
- Offline lookups (no API rate limits to deal with)
- Pretty much anything where you need to map ASNs to operators
- as-overlay: Autonomous system metadata overlays that supplement and enhance the authoritative data in this repository. When overlay data is applied, entries will have an
originvalue ofoverlaidin the JSON format.
Head over to the feedback repository if you have questions, issues, or suggestions.
This data is released under CC0 1.0 Universal.