# ASN Neighbours Lookup

> ASN Neighbours Lookup is a paid API for AI agents from netz.halowerk.com, paid per call via x402, $0.004/call, status unknown (last checked 2026-09-14).

Returns the neighbouring autonomous systems observed adjacent to a given AS in BGP paths, with observer counts and adjacency frequency indicating observation confidence.

## Facts

- Endpoint: POST https://netz.halowerk.com/v1/asn-neighbours
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/asn-neighbours-lookup-0ebe345a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_1BTVjTxzOBNPRzZPIVNVC

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability asn-neighbours-lookup-0ebe345a -d '<json body>'
```

Example prompt: What autonomous systems are BGP neighbours of AS15169? I want to know which ASes appear next to it in observed BGP paths, how many RIS observers saw each adjacency, and how often each one appeared.

## When to prefer this

Use this endpoint when you need to understand the observed BGP topology around a specific autonomous system — particularly which ASes are directly adjacent in routing paths and how well-attested those adjacencies are. Prefer this over passive BGP route tables when you want observation confidence metrics (observer count + frequency). It complements RPKI validation and route hijack detection endpoints for full routing security analysis.

## Known failure modes

- Invalid or non-existent ASN returns an error or empty neighbour list
- ASN with very limited BGP visibility may return few or no neighbours
- Stale data if BGP observations have not been refreshed recently
- Malformed request body returns a 400-level error

## How this service works

Returns the neighbouring autonomous systems observed next to a given AS in BGP paths, each with the number of observers that saw the adjacency and how often it appeared, which together indicate how solid the observation is rather than how important the relationship is.

## Output

A list of neighbouring autonomous systems observed adjacent to the queried ASN in BGP paths. Each neighbour entry includes the neighbour's ASN, the number of distinct BGP observers (RIS peers) that saw the adjacency, and the count of how often that adjacency appeared in BGP paths — together indicating the reliability and solidity of the observed peering relationship.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "asn": {
   "type": "string",
   "maxLength": 15,
   "minLength": 1
  },
  "min_peers": {
   "type": "integer",
   "default": 3,
   "maximum": 100,
   "minimum": 1,
   "description": "Adjacencies seen by fewer observers than this are marked weak."
  },
  "compare_days_ago": {
   "type": "integer",
   "maximum": 365,
   "minimum": 1,
   "description": "Compare against the neighbour set this many days ago."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/asn-neighbours-lookup-0ebe345a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from netz.halowerk.com](https://www.zero.xyz/host/netz.halowerk.com/llms.txt)