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JSON Validator & Linter

Validation-firstFreePrivateBrowser-only

Validate JSON syntax instantly, detect formatting issues, and understand errors before deployment. Great for APIs, config files, frontend apps, and debugging workflows.

  • Validate JSON fast
  • Clear error messages
  • Fix syntax issues
  • Private browser processing
JSON input

Paste JSON to validate syntax and structure.

Validation result
Ctrl+Enter Validate JSON  ·  Ctrl+Shift+M Minify

JSON Validator and Linter Online

Check whether your JSON is valid instantly. Detect syntax errors, understand parser issues, and clean up JSON before using it in APIs, apps, configs, or production systems.

Where Is This Useful?

Before shipping APIs
Validate response payloads before they leave your backend. A bad JSON response that silently reaches the client can be harder to trace than catching the error at the source. Paste the response body here first.
Config files and fixtures
JSON config files edited by hand are prone to trailing commas, missing quotes, or bracket mismatches. Validate before committing. If the input is almost-valid, use JSON Repair to auto-fix the common cases first.
Debugging parse errors
When JSON.parse() throws and the position offset is useless, paste the raw string here to get a line and column number. For a guided walkthrough of each error type, see JSON Parse Error.

How to Use

  1. Paste JSON input.
  2. Click Validate JSON (or press Ctrl+Enter).
  3. Review the result: valid output appears in the panel, or an error with line and column.
  4. Fix issues and validate again, or use Format when the document is valid.
  5. Copy or download the output when you are ready.

Features

  • Instant JSON validation
  • Clear syntax error guidance
  • Format and minify options
  • Browser-only private processing
  • Mobile friendly
  • Helpful debugging workflow

Frequently Asked Questions

Is this validator free?

Yes. No sign-up required.

Is my data uploaded?

No. Everything runs locally in your browser.

What makes JSON invalid?

Common causes include trailing commas, unquoted keys, single-quoted strings, comments, bad escapes, or mismatched braces and brackets.

Can it show line numbers?

Yes. Errors include line and column for the first parse failure, plus a short explanation and the offending line when helpful.

Can I format valid JSON too?

Yes. Use Format or Minify after validation passes, or open the mobile sheet for more actions.

What does linter mean here?

Syntax validation plus optional light hints when the input is valid—such as very long one-line JSON or mixed tab and space indentation. For schema rules, use a JSON Schema workflow.

Does it work on mobile?

Yes. Editors and the sticky bar prioritize Validate JSON with copy and more actions one tap away.

Can I validate API responses?

Yes. Paste bodies from DevTools, curl, or logs to confirm strict JSON before parsing in application code or saving fixtures.

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