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Utilnivo

Developer

Utilnivo

JSON Validator

Validate JSON syntax and show parse errors.

No registration
  • On your device

Browse more in Developer or all tools.

Private on your device

Your information stays on your device and is not uploaded.

Related tools

Paste JSON to validate syntax instantly. Invalid JSON shows parse errors with line and column when available. Validation works on your device.

How to use this tool

1. Paste JSON. 2. Validate. 3. Fix reported syntax issues (trailing commas, quotes). 4. Re-validate. 5. Use JSON Formatter when you also need pretty-print or minify.

Worked example

Example 1: trailing comma after the last property fails parse—remove it. Example 2: single-quoted keys fail—switch to double quotes per JSON spec.

When to use this

  • Validating API payloads before sending.
  • Checking config files for trailing commas.
  • Teaching JSON syntax vs JavaScript object literals.
  • Linting exported CMS JSON.
  • Separating syntax validation from schema checks.

Common examples

  • Trailing comma error on last object property.
  • Single quotes rejected—use double quotes.
  • Unescaped newline inside a string value.
  • Large config file validates after removing comments (JSONC ≠ JSON).
  • Empty input vs {} — empty is invalid; empty object is valid.

Common mistakes

  • Expecting schema/OpenAPI validation here.
  • Leaving // comments in strict JSON.
  • Using single quotes.
  • Confusing formatter vs validator intents.
  • Uploading secrets to third-party linters—use local tools.

How it works

Parses JSON with the browser JSON parser and reports syntax errors (and location hints when available). Validates structure only—not a schema/OpenAPI checker.

Limitations

Validates JSON syntax only. Schema, business rules, and duplicate keys are not checked unless noted.

Privacy and file handling

Your data stays on your device and is not uploaded.

Formula or method

JSON.parse on your device. Schema validation is out of scope; pair with a schema tool when you need type constraints.

Related JSON Validator workflows

Explore focused guides that reuse this json validator with different examples and FAQs.

FAQ

Frequently asked questions

What does JSON Validator check?

Syntax only—whether the text parses as JSON. It does not validate against a JSON Schema or OpenAPI document.

Why do trailing commas fail?

Strict JSON disallows trailing commas after the last property or array element. Remove them or use a JSONC-aware toolchain if you need comments/commas.

Should I use Formatter or Validator?

Use Validator to find parse errors quickly; use JSON Formatter when you also want pretty-print, minify, or key sorting.

Part of these workflows

This tool is one step in a longer job. Jump straight to your step or open the full workflow guide.

Related pages

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