Developer Utilities · Free tool
JSON Validator
Validate JSON with native browser parser. Errors point to line/column. Reports size, nodes, and max depth.
✓ Valid JSON
Bytes
162
Minified
124
Nodes
11
Max depth
2
Uses your browser’s native JSON parser, so errors match what Node.js / Python / any standard parser would report. Common issues: trailing commas (not allowed in JSON), single quotes (must be double), comments (not allowed in standard JSON — use JSON5 if you need them).
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What it does
Validate JSON with line/column error reporting. Uses your browser’s native parser, so error messages match what Node.js / Python / any standard library would produce. When valid, also reports byte size, minified size, total nodes, and max nesting depth.
Embed this tool on your siteShow snippetHide
Paste this snippet into any page. Loads on-demand (lazy), no tracking scripts, and sized to most dashboards. Replace the height to fit your layout.
<iframe src="https://freetoolarena.com/embed/json-validator" width="100%" height="720" frameborder="0" loading="lazy" title="JSON Validator" style="border:1px solid #e2e8f0;border-radius:12px;max-width:720px;"></iframe>How to use it
- Paste your JSON.
- Watch validity update live.
- If invalid, the error message + line/column points to the exact problem.
Frequently asked questions
- Can I use comments in JSON?
- Standard JSON (RFC 8259) doesn't allow comments. JSON5 and JSONC do. If you need comments, your stack needs to be using one of those parsers — strict JSON.parse will reject any // or /* */.
- What about trailing commas?
- Strict JSON disallows them. JSON5 / JSONC allow them. Most production parsers (especially in browsers and APIs) reject trailing commas.
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