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).
Advertisement
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.
Advertisement
Learn more
Guides about this topic
- Using Our Tools · GuideHow to generate QR codesMake a QR code for a URL, wifi, vCard, or plain text. What error-correction means, how big to print, how to test it.
- Using Our Tools · GuideHow to create a strong passwordThe entropy math, 2026 NIST rules, passphrases vs passwords, password managers, MFA and hardware keys, where passkeys fit, 5 mistakes that still lose accounts
- Developers & Technical · GuideHow to encode and decode Base64What Base64 is (not encryption), the 3-to-4 encoding mechanics, standard vs URL-safe vs MIME variants, 33% overhead, when to use it, common mistakes
- Design & Media · GuideHow to choose a color paletteHSL color theory, four palette schemes (monochromatic, analogous, complementary, triadic), the 60-30-10 rule, WCAG contrast, dark mode, and palette tools.
- Developers & Technical · GuideHow to use JWT tokens securelyJWT anatomy, HS256 vs RS256, the 'alg: none' attack, expiration strategy, storage (localStorage vs httpOnly cookies), revocation patterns, and claim validation.
- Design & Media · GuideHow to design a faviconThe sizes you actually need in 2026, design principles that survive 16×16 rendering, dark mode support, the HTML tags, web manifest, and testing.
Explore more developer utilities tools
- .htaccess GeneratorGenerate Apache .htaccess with HTTPS redirect, Gzip, caching, error pages, hotlink protection, 301 redirects.
- Color Palette ExtractorExtract dominant colors from any image. Histogram-based, runs in browser. Click swatches to copy hex.
- XML Sitemap GeneratorGenerate sitemap.xml from a URL list. Sets lastmod to today, applies priority and changefreq. Download or copy.
- JavaScript MinifierStrips comments and collapses whitespace from JS. For production minification, use terser or esbuild.
- HTML Table GeneratorInteractive HTML table builder. Click cells to edit. Toggle headers, stripes, borders. Inline-styled output for emails.
- CSS Button GeneratorVisual CSS button generator. Hover, active, and focus-visible states baked in. Tunable colors and sizing.