JavaScript Lint API

JavaScript / Node lint: POST {code}, get the bugs back with line numbers. Syntax errors come from the real V8 parser (compile-only — code is never executed), plus deterministic checks: loose == coercion, assignment in conditions, comparisons with NaN, const reassignment (runtime TypeError), var pitfalls, unused variables, leftover console.log. Handles ESM imports, template literals, regex. No AI. Max 128 KB.

Parameters

Example request

curl -X POST "https://api.webbersites.com/api/lint/javascript" \
  -H "Content-Type: application/json" \
  -d '{"code":"const limit = 10;\nif (value == NaN) { stop(); }\nlimit = 20;"}'
# first call returns 402 + payment requirements; an x402 client pays and retries automatically

Example response

{
    "language": "javascript",
    "syntax": {
        "ok": true,
        "errors": []
    },
    "issues": [
        {
            "line": 2,
            "severity": "error",
            "rule": "nan-compare",
            "message": "nothing is ever == NaN — this comparison is always false",
            "hint": "use Number.isNaN(x)"
        }
    ],
    "counts": {
        "error": 2,
        "warning": 0,
        "info": 0
    },
    "verdict": "errors"
}

How payment works

There is no signup and no API key. Call the endpoint; it replies 402 Payment Required with machine-readable payment requirements. Your client signs a USDC transfer authorization (EIP-3009, gasless) and retries with the X-PAYMENT header — @x402/fetch does this automatically. See the overview for a working snippet.