Skip to content
ForgePlug — Logo
Developer100% Browser-Based

JSON Validator

A focused JSON validation tool that provides real-time validation as you type. Get clear, human-readable error messages with exact line and column locations, plus detailed JSON statistics including key counts, nesting depth, and data type breakdowns.

Waiting for input
JSON Input
Ln 1Col 10 charsUTF-8JSONSpaces: 2

Paste JSON or upload a file to validate

Validation happens in real-time as you type

Examples

Click an example to load it into the validator.

Valid JSON Object

Error
{
  "name": "ForgePlug",
  "version": "1.0.0",
  "features": ["format", "minify"...

Trailing Comma Error

Error
{
  "name": "Alice",
  "age": 30,
  "city": "New York",
}

Missing Quote

Error
{
  "status": "active",
  count: 42
}

Valid JSON Array

Error
[
  {
    "id": 1,
    "product": "Widget",
    "price": 9.99
  },
  {
    "id":...

Unclosed Brace

Error
{
  "settings": {
    "theme": "dark",
    "notifications": true
}

Frequently Asked Questions

How does JSON validation work?
The validator parses your JSON input using JavaScript's built-in JSON parser. If the JSON is valid, it parses successfully and you'll see a success message. If there's a syntax error, the parser throws an error which we capture and translate into a human-readable message with the exact line number, column position, and a description of what went wrong.
Is my data sent to a server?
No. All validation happens entirely in your browser. Your JSON data never leaves your device. This is a core privacy feature of ForgePlug — everything is client-side with no server uploads.
What does real-time validation mean?
As you type or paste JSON, the validator automatically checks your input with a short delay (300ms) after you stop typing. This gives you instant, continuous feedback — you'll see errors appear and disappear as you edit, without needing to click any button.
What kind of errors can the validator detect?
The validator catches all JSON syntax errors including: missing or extra commas, unclosed braces or brackets, missing quotes around keys or string values, invalid number formats, unexpected tokens, and unterminated strings. Each error includes the exact line and column where the problem occurred.
What do the JSON statistics tell me?
The statistics panel shows you structural information about your JSON: total number of keys, number of arrays, maximum nesting depth, data types detected (strings, numbers, booleans, nulls), total character count, and the parsed data type (object or array at the root). This helps you understand the shape and size of your data at a glance.
Can I validate JSON files?
Yes. Click the Upload button or drag and drop a .json file into the editor. The file contents are read and loaded into the input area for validation. All processing stays client-side — no file is uploaded to any server.
How are error messages different from raw parser errors?
Raw JavaScript parser errors can be cryptic (e.g., 'Unexpected token } in JSON at position 42'). We translate these into clear, friendly messages like 'Extra closing brace } at line 5, column 3.' We also highlight the exact location so you can fix the issue quickly.

Frequently Asked Questions

Everything you need to know about validating JSON

How does JSON validation work?
The validator parses your JSON input using JavaScript's built-in JSON parser. If the JSON is valid, it parses successfully and you'll see a success message. If there's a syntax error, the parser throws an error which we capture and translate into a human-readable message with the exact line number, column position, and a description of what went wrong.
Is my data sent to a server?
No. All validation happens entirely in your browser. Your JSON data never leaves your device. This is a core privacy feature of ForgePlug — everything is client-side with no server uploads.
What does real-time validation mean?
As you type or paste JSON, the validator automatically checks your input with a short delay (300ms) after you stop typing. This gives you instant, continuous feedback — you'll see errors appear and disappear as you edit, without needing to click any button.
What kind of errors can the validator detect?
The validator catches all JSON syntax errors including: missing or extra commas, unclosed braces or brackets, missing quotes around keys or string values, invalid number formats, unexpected tokens, and unterminated strings. Each error includes the exact line and column where the problem occurred.
What do the JSON statistics tell me?
The statistics panel shows you structural information about your JSON: total number of keys, number of arrays, maximum nesting depth, data types detected (strings, numbers, booleans, nulls), total character count, and the parsed data type (object or array at the root). This helps you understand the shape and size of your data at a glance.
Can I validate JSON files?
Yes. Click the Upload button or drag and drop a .json file into the editor. The file contents are read and loaded into the input area for validation. All processing stays client-side — no file is uploaded to any server.
How are error messages different from raw parser errors?
Raw JavaScript parser errors can be cryptic (e.g., 'Unexpected token } in JSON at position 42'). We translate these into clear, friendly messages like 'Extra closing brace } at line 5, column 3.' We also highlight the exact location so you can fix the issue quickly.

Share this tool

Share
Runs in your browser100% privateNo data uploaded