Service metadata

Code snippets

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

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

$ch = curl_init("https://api.oanor.com/isotopes-api/v1/meta");
curl_setopt($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/isotopes-api/v1/meta",
    headers={"x-oanor-key": "oanor_test_..."}
)

Example response

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

{
    "data": {
        "service": "isotopes-api",
        "endpoints": {
            "GET /v1/list": "List isotopes (naturally_occurring=true to filter, limit, offset).",
            "GET /v1/meta": "This document.",
            "GET /v1/rank": "Rank isotopes by metric (by=atomic_mass|abundance|mass_number, order, limit).",
            "GET /v1/search": "Search isotopes by symbol, name or label (q=).",
            "GET /v1/element": "All isotopes of an element (symbol=C or z=6).",
            "GET /v1/isotope": "Isotope by id (id=C-12 or U-238), or symbol= + mass=, or z= + mass=."
        },
        "description": "NIST atomic isotope reference for every known nuclide: element (Z, symbol), mass number, relative atomic mass, natural isotopic composition and standard atomic weight. Look up an isotope (C-12, U-238), list an element's isotopes, rank by mass or abundance, or search. Distinct from elements-api. No key.",
        "total_isotopes": 3180,
        "rankable_metrics": [
            "atomic_mass",
            "abundance",
            "mass_number"
        ],
        "distinct_elements": 118,
        "naturally_occurring": 288
    },
    "meta": {
        "timestamp": "2026-06-09T03:03:47.785Z",
        "request_id": "9992d37a-b58b-48d3-91c4-bf2e724af8b4"
    },
    "status": "ok",
    "message": "Meta",
    "success": true
}