Liquid Lint API

Liquid / Shopify theme lint: POST {code}, get the bugs with line numbers. Deterministic — never rendered, no AI. Catches unbalanced/misnested blocks, unknown tags/filters with did-you-mean, the JS-isms every dev writes in Liquid (&&, !, ternaries, arithmetic in output, parens in conditions), deprecated img_url/include, and FULL {% schema %} validation: setting types, duplicate ids, range/select rules, blocks, presets. POST bare schema JSON to test just a schema. Max 128 KB.

Parameters

Example request

curl -X POST "https://api.webbersites.com/api/lint/liquid" \
  -H "Content-Type: application/json" \
  -d '{"code":"{% if product.available && product.price %}\n  {{ product.price + 10 | money }}\n{% endfor %}"}'
# first call returns 402 + payment requirements; an x402 client pays and retries automatically

Example response

{
    "language": "liquid",
    "syntax": {
        "ok": false,
        "errors": [
            {
                "line": 3,
                "severity": "error",
                "rule": "syntax/unbalanced-block",
                "message": "{% endfor %} closes {% for %}, but the innermost open block is {% if %} (line 1)"
            }
        ]
    },
    "issues": [
        {
            "line": 1,
            "severity": "error",
            "rule": "logic/js-operator",
            "message": "'&&' is not Liquid (condition) — expressions with it fail",
            "hint": "use 'and'"
        }
    ],
    "counts": {
        "error": 3,
        "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.