JSON5 Validator

Definition

JSON5 with comments and trailing commas. On JSON Nova, the workflow runs entirely in your browser with no server processing of your data. Suitable for sensitive payloads, large files, and offline use as a PWA.

JSON5 with comments and trailing commas. Validate or format in browser. Stricter JSON available via JSON Validator. See also JSON to CSV and JSON Formatter.

Run everything in your browser with Monaco Editor on JSON Nova—100% client-side, no server uploads, large-file friendly. Install as a PWA for offline use.

Guide and tips

Developer guide

Short, practical notes—workflow, common mistakes, and pro tips—with links to related tools.

Validate JSON5

JSON5 with comments and trailing commas. Validate or format in browser. Stricter JSON available via JSON Validator.

All processing stays in your browser. Paste production-shaped samples without uploading secrets.

Strict vs loose sources

Know whether your payload must match a strict grammar or allow extensions.

Related: JSON Formatter, JSON Validator.

Common mistakes

Trusting “it looked fine” without running the official validator.

Validating once and never again after edits.

Ignoring line/column hints when the spec error message is dense.

Pro tips

Wire the same checks into CI as you use here.

Related: JSON Formatter, JSON Validator.

Quick reference

What is JSON5?

**JSON5** extends JSON with comments and relaxed syntax. This tool validates JSON5 locally.

Use cases

  • Config files and human-edited data.
  • Migrating to strict JSON via repair.

Common errors

  • Still invalid tokens or unclosed structures.
  • Confusion with JSONC—validate expectations.

Best practices

Export to strict JSON for APIs. Use JSON Validator on output when standards require JSON.

Performance and privacy

Performance

Leverage the power of Monaco Editor and Web Workers. Our toolkit is optimized for files up to 50MB, providing real-time transformations without lag.

Privacy

Your data stays local. Conversions and formatting run 100% in your browser—nothing is sent to our servers.

Frequently asked questions

FAQ

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Is JSON5 validation different from standard JSON?

Yes, a JSON validator will fail on comments or trailing commas, while a JSON5 validator will approve them.

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Are single quotes allowed?

Yes, JSON5 allows single quotes exactly like JavaScript, and our validator natively handles them.

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Does data leave my browser?

No, all JSON5 validations occur exclusively in your browser local memory.

More tools

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JSON5 Formatter

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Base64 encode in your browser. No server. Safe for quick encode/decode tasks. Pair with JSON tools when needed.

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