# geo402 Great-Circle Distance

> geo402 Great-Circle Distance is a paid API for AI agents from 69.67.172.228.sslip.io, paid per call via x402, $0.001/call, status down (last checked 2026-09-15).

Calculates the great-circle (shortest path) distance between two geographic coordinates, returning the result in the requested unit.

## Facts

- Endpoint: GET https://69.67.172.228.sslip.io/v1/distance
- Price: $0.001/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/geo402-great-circle-distance-33dd53f6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_sqOnp-L7mtRpA_-2ErN4I

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 geo402-great-circle-distance-33dd53f6
```

Example prompt: What is the great-circle distance in kilometers between the coordinates 40.7128, -74.0060 (New York City) and 51.5074, -0.1278 (London)?

## When to prefer this

Use this endpoint when you need a fast, pay-per-call great-circle distance computation between two GPS coordinate pairs without committing to a subscription or obtaining an API key. Ideal for AI agents that need occasional or on-demand geospatial distance calculations and support x402 or MPP micropayment protocols (Base/USDC or Tempo/pathUSD).

## Known failure modes

- Missing required parameters (lat1, lat2, lon1, lon2) returns a 400 error
- Invalid non-numeric coordinate values return a validation error
- Coordinates out of valid range (latitude outside -90 to 90, longitude outside -180 to 180) may return an error
- Payment not included or insufficient USDC returns a 402 Payment Required response
- Invalid or unsupported unit string may return an error or default to a standard unit

## How this service works

Pay-per-call geolocation utility for AI agents: geocoding, reverse geocoding, timezone lookup, and great-circle distance. No API key, no subscription — agents pay per request via x402 (Base/USDC) or MPP (Tempo/pathUSD).

## Output

Returns the computed great-circle (shortest spherical path) distance between the two provided coordinate pairs, expressed in the requested unit (e.g., kilometers or miles). The response is a numeric distance value along with the unit.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "lat1",
  "lat2",
  "lon1",
  "lon2"
 ],
 "properties": {
  "lat1": {
   "type": "number",
   "description": "Start latitude in decimal degrees."
  },
  "lat2": {
   "type": "number",
   "description": "Destination latitude in decimal degrees."
  },
  "lon1": {
   "type": "number",
   "description": "Start longitude in decimal degrees."
  },
  "lon2": {
   "type": "number",
   "description": "Destination longitude in decimal degrees."
  },
  "unit": {
   "enum": [
    "km",
    "mi",
    "m",
    "nmi"
   ],
   "type": "string",
   "description": "Distance unit: kilometers, miles, meters, or nautical miles."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/geo402-great-circle-distance-33dd53f6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from 69.67.172.228.sslip.io](https://www.zero.xyz/host/69.67.172.228.sslip.io/llms.txt)