Spec

Code snippets

curl "https://api.oanor.com/chain-api/v1/meta" \
  -H "x-oanor-key: oanor_test_..."

await fetch("https://api.oanor.com/chain-api/v1/meta", {
  headers: { "x-oanor-key": "oanor_test_..." }
});

$ch = curl_init("https://api.oanor.com/chain-api/v1/meta");
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$out = curl_exec($ch);

import requests
requests.get(
    "https://api.oanor.com/chain-api/v1/meta",
    headers={"x-oanor-key": "oanor_test_..."}
)

Example response

A real response from this endpoint, captured by the latest health check.

{
    "data": {
        "notes": "Teeth counts are integers, pitch and centre distance in m (default pitch 0.0127 m = ANSI 40, ½\"). Link counts must be even.",
        "service": "chain-api",
        "formulae": {
            "ratio": "ratio = N2/N1 ; v = N·p·rpm/60",
            "length": "L = 2C/p + (N1+N2)/2 + ((N2−N1)/2π)²·p/C",
            "pitch_diameter": "PD = p/sin(π/N)"
        },
        "endpoints": {
            "GET /v1/meta": "This document.",
            "GET /v1/ratio": "Speed ratio, output rpm, chain velocity and pitch diameters from sprocket teeth.",
            "GET /v1/length": "Chain length in pitches and even links from the centre distance.",
            "GET /v1/center-distance": "Centre distance for a given even number of links."
        },
        "description": "Roller-chain drive calculator: speed ratio, chain velocity and pitch diameters; chain length in links from the centre distance; and the centre distance for a chosen link count."
    },
    "meta": {
        "timestamp": "2026-06-05T11:30:26.013Z",
        "request_id": "b4e9de70-0139-4af4-be6e-563da488a2b5"
    },
    "status": "ok",
    "message": "Meta",
    "success": true
}