Great-Circle Distance (haversine)

Distance (km/mi/nautical) and initial bearing between two lat/lon points.

Free tier eligible — 500 calls/month with a free key from /pricing; x402 pay-per-call above quota.

Parameters

Parameter	Type	Required	Description
`lat1`	number	required	Latitude of point 1 (-90..90)
`lon1`	number	required	Longitude of point 1 (-180..180)
`lat2`	number	required	Latitude of point 2 (-90..90)
`lon2`	number	required	Longitude of point 2 (-180..180)

Call it over MCP (JSON-RPC 2.0)

curl -s https://wingmanprotocol.com/mcp \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json, text/event-stream' \
  -d '{"jsonrpc": "2.0", "id": 1, "method": "tools/call", "params": {"name": "haversine", "arguments": {"lat1": 100, "lon1": 100, "lat2": 100, "lon2": 100}}}'

Or plain HTTP

curl -s https://wingmanprotocol.com/tools/haversine \
  -H 'Content-Type: application/json' \
  -d '{"lat1": 100, "lon1": 100, "lat2": 100, "lon2": 100}'

Try it live

Edit the JSON and run it — this POSTs to https://wingmanprotocol.com/tools/haversine from your browser.

This tool is x402-metered — agents pay per call with USDC on Base. The 402 response below is the standard x402 payment-requirements envelope: sign the EIP-3009 authorization and retry with the X-Payment header, or get a free key at /pricing (500 calls/month, no card, no crypto).