as-metadata (formerly asn-info)

March 4, 2026 · View on GitHub

🔍 Try it online

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.

Update notes

2026-03-04: Added metadata.lastModified and stats.prefixesLastModified change-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) and networkRole (e.g. tier1_transit, stub) fields to AS metadata
2026-01-27: Added providerAsns field with list of upstream transit provider ASNs
2026-01-18: Breaking change: Replaced upstreams/downstreams with providers/customers/peers to accurately distinguish transit relationships from peering. Added degree and reach fields.
2026-01-08: Added registered field (RIR registration date), stats section (prefix and connectivity statistics), and moved lastAnnounced to 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

Available formats

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-code
0,IANA-RSVD-0,Internet Assigned Numbers Authority,US
1,LVLT-1,Level 3 Parent LLC,US
2,UDEL-DCN,University of Delaware,US
3,MIT-GATEWAYS,Massachusetts Institute of Technology,US
4,ISI-AS,University of Southern California,US
5,SYMBOLICS,WFA Group LLC,US
6,BULL-HN,ATOS IT Solutions and Services Inc.,US
7,DSTL,The Defence Science and Technology Laboratory,GB
.
.
.

Field descriptions

CSV fields

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)

JSON fields

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

Origin values

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

AS category and network role

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

Network role

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.

How to use

Download the data directly:

JSON:

curl -O https://raw.githubusercontent.com/ipverse/as-metadata/master/as.json

CSV:

curl -O https://raw.githubusercontent.com/ipverse/as-metadata/master/as.csv

Or just clone the repo if that's your thing.

Quick example (Python):

import json
with open('as.json') as f:
    data = {entry['asn']: entry for entry in json.load(f)}
print(data[4711]['metadata']['description'])  # INTEC Inc.

Use cases

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 origin value of overlaid in the JSON format.

Questions or issues?

Head over to the feedback repository if you have questions, issues, or suggestions.

License

This data is released under CC0 1.0 Universal.