Categories

Finance
Business
Text
Converters
Creator
Image
Legal
Productivity
Developer
Misc
YouTube
Sign In

JSON Validator

Validate JSON syntax and see detailed error messages with line numbers.

Debugging invalid JSON can be frustrating, especially with large payloads where a single missing comma or extra bracket breaks everything. This JSON validator checks your JSON syntax and provides clear error messages to help you find and fix problems quickly.

When the JSON is valid, the tool reports the root data type (object or array) and the number of top-level keys or items. Everything runs in your browser with no data sent to any server.

Validator

Results

—
—
—
—

How to Use

  1. Paste your JSON into the input field
  2. Click Calculate to validate
  3. Review the validation result and any error details
  4. Fix errors and re-validate as needed

FAQ

What errors does it detect?

The tool detects all JSON syntax errors including missing commas, mismatched brackets, invalid escape sequences, trailing commas, and unquoted keys.

Does it show where the error is?

Yes. The error message includes position information to help you locate the problem in your JSON.

Is my JSON sent to a server?

No. All validation runs in your browser. Your data never leaves your device.

Related Tools

You might also like these tools

JSON Formatter

Beautify or minify JSON with customizable indentation. Validates syntax automatically.

Regex Tester

Test regular expressions against text. See all matches highlighted with capture groups.

Word Counter

Count words, characters, sentences, paragraphs, and estimate reading time for any text.

CSV to JSON Converter

Convert CSV data to JSON format instantly. First row is used as keys.

Character Counter

Count characters with and without spaces, plus letters, digits, and special characters.

Fancy Text Generator

Transform text into fancy Unicode styles — bold, italic, script, monospace, circled, and more.

JSON to CSV Converter

Convert a JSON array of objects to CSV format with automatic header detection.

Paragraph Counter

Count paragraphs, average words per paragraph, and total word count for any text.

Sentence Counter

Count sentences, average words per sentence, and longest/shortest sentence in any text.

Text Deduplicator

Remove duplicate lines from text. Keep only unique lines with optional case-insensitive matching.

Learn More

Guides that feature this tool

JSON & API Tools: The Developer's Browser-Based Toolkit

Format JSON, decode JWTs, generate UUIDs, and test regex — all from your browser with zero setup.

8 min read

CSV and JSON Data Transformation: Converting, Cleaning, and Validating

Learn when to use CSV versus JSON, how to convert between them cleanly, and how to avoid common data transformation pitfalls.

7 min read

Part of These Collections

Curated tool sets for specific workflows

JSON Tools

Working with JSON is a daily task for developers, whether you are debugging API responses, converting data formats, or validating configuration files. This collection puts every JSON utility you need in one place, from formatting and validation to conversion between JSON, CSV, XML, and YAML.

Essential Developer Tools

Every developer has a set of go-to utilities they reach for daily — formatting JSON, testing regex patterns, generating UUIDs, hashing strings, or decoding Base64. This collection brings those essentials together in one place so you can stop searching and start building.