JSON5 Validator — Check JSON5 Syntax With Error Reporting

How to use

1. 1 Paste your JSON5 — comments, trailing commas, single quotes all welcome.
2. 2 See the green Valid pill, or a red error pill with line and column.
3. 3 The right pane shows the parsed value as standard JSON.
4. 4 Copy or download the JSON output.

Why use this tool

• Powered by <code class="font-mono text-xs">json5</code> — the reference JSON5 implementation.
• JSON5 lets you author config files with comments, trailing commas, hex numbers, and more.
• Errors include line and column so you can find them fast.
• Pure client-side — input stays in your browser.

Frequently asked questions

What is JSON5 Validator?

A JSON5 Validator is a tool that checks whether text conforms to the JSON5 specification and reports syntax errors with line and column positions. It accepts JSON5 features that standard JSON rejects, including comments, trailing commas, single-quoted strings, and hexadecimal numbers. Running client-side in the browser, it validates and parses JSON5 input without uploading it to a server.

Features

Example

{ /* comment */ a: 1, b: 'two', c: 0xff, }

Valid ✓  → parses to {"a":1,"b":"two","c":255}

Common use cases

1. 1

   Validate config files

   Check a .json5 or JSON5-style config (Babel, some build tools) before committing.

2. 2

   Catch trailing-comma issues

   Confirm which relaxed features your input uses and where it still errors.

3. 3

   Convert JSON5 to JSON

   Parse JSON5 to see the strict-JSON value it represents.

References

• The JSON5 Data Interchange Format — Specification — JSON5
• json5 — reference parser — GitHub

Learn the basics

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