Strict local JSON validator

JSON Validator Online

Check whether JSON is valid and get a precise location when it is not. The validator never silently repairs your source.

Local processing · private

Input JSON6 lines · 143 B

Ctrl/⌘ + Enter to runPaste, type, or drop a .json file

Valid JSON

Valid object root · 6 lines · 143 B

Processed in your browser

Standard JSON validation

No account or upload

01 — 03

A clear validation result in three steps

The validator keeps your source intact and reports the first standards-level parsing error it finds.

Paste the original JSON

Add text exactly as received or open a local .json file.

Run strict validation

Check the document with the browser's standard JSON parser without conversion or cleanup.

Fix with context

Use the reported line, column, and nearby source line to correct the original document.

EXAMPLES & SYNTAX

Input, output, and common errors

The parser preserves JSON values while changing only the representation required by this tool.

INPUT

{
  "site": "jsonminify.org",
  "enabled": true,
  "items": [1, 2]
}

OUTPUT

Valid JSON — 4 lines, 3 properties

CaseValid formWhy it matters

Object keys{"name":"value"}

Keys and string values require double quotes.

Arrays[1, 2, 3]

Items keep their original order.

Primitive valuestrue · false · null

These tokens are lowercase and are not quoted.

Whitespacespace · tab · line break

Optional outside strings; meaningful inside quoted strings.

Invalid JSON example{ "enabled": true, }

A trailing comma is valid in some JavaScript contexts but not in JSON. Remove it before running parsed operations.

WHY JSONMINIFY.ORG

A validator that does not hide the problem

Validation is separate from formatting so a successful result means the submitted source is valid JSON.

Preserves the source

Your input remains unchanged whether validation succeeds or fails.

Actionable location

Errors include a line, column, source excerpt, and pointer when the browser provides a position.

Standard JSON rules

Comments, trailing commas, undefined values, and JavaScript object syntax are rejected.

COMMON USE CASES

What to check with a JSON validator

Syntax validation is a fast first step whenever JSON crosses a boundary between people, applications, or environments.

Debug an API request

Check a request body before sending it so syntax errors are separated from authentication, routing, or server-side validation failures.

Verify exported configuration

Confirm that a generated or manually edited configuration file is syntactically complete before importing it into another system.

Investigate a failed build

Locate malformed JSON in package metadata, translation files, manifests, fixtures, or generated build artifacts.

Review third-party data

Validate JSON received in email, tickets, logs, or integrations before using it in a script or development tool.

JSON REFERENCE

Understanding JSON validation results

Syntax validation answers whether text can be parsed as JSON. It does not prove that the data is correct for a particular application.

Keys and strings require double quotes

Standard JSON uses double quotes for object keys and string values. Single quotes and unquoted keys belong to JavaScript object syntax, not JSON.

Comments and trailing commas are rejected

JSON has no comment syntax, and the final item in an object or array cannot be followed by a comma. Remove these before validating again.

Any JSON value can be the root

Objects and arrays are common, but a string, number, boolean, or null can also be a complete valid JSON document when the receiving system permits it.

Syntax validity is not schema validity

A valid document may still be missing required properties or contain values of the wrong business type. Those rules require a separate schema or application-level check.

FAQ

JSON validation, without ambiguity

Understand what a valid result means and why some JavaScript-like input is rejected.

What JSON standard does this validator use?

It uses the browser's native JSON parser, which accepts standard JSON values and rejects JavaScript-only syntax.

Does validation fix invalid JSON?

No. It keeps the original source and reports the error so you can decide how to correct it.

Why does the validator stop at one error?

Standard parsers stop at the first blocking syntax error. Fixing it can reveal a later issue on the next run.

Is validation performed on a server?

No. The JSON is parsed locally in your browser and is not included in analytics events.