JSON Tools

JSON Parser Online

Run a real JSON parse in your browser — see exactly what your application will see, or exactly where it will fail.

In short

A JSON parser turns JSON text into structured data — objects, arrays, strings, numbers, booleans and null — and stops at the first grammar violation. This page runs the browser's native JSON.parse, so whatever passes or fails here behaves identically in Node.js and every browser; it reports the failing line and column, shows the parsed tree, and counts nodes, depth and bytes.

By NaveenKumar T · Updated 18 Sep 2026

Learn: JSON Crack Alternative Without Signup: Viewing JSON as a Tree

True JSON.parse semantics
Exact error line & column
Parsed structure as a tree

Runs entirely in your browser — nothing you paste or open here is uploaded, logged, or stored.How we handle data →

Example

JSON Parser: input and output

A compact payload with a nested object and array, parsed and re-printed with 2-space indentation.

Compact JSON

{"user":{"id":482,"name":"Priya Shah","roles":["admin","editor"]},"active":true}

Parsed & formatted

{
  "user": {
    "id": 482,
    "name": "Priya Shah",
    "roles": [
      "admin",
      "editor"
    ]
  },
  "active": true
}

The parse succeeded, so the tree view and stats panel (2 top-level keys, one nested array) are available too — a syntax error anywhere would have stopped at that exact line and column instead of producing this output.

Learn more

Parse JSON online: what the parser reports

Parsing is where JSON stops being text and becomes data. The parser walks the document character by character, enforcing the grammar: keys must be double-quoted strings, values must be one of six types, commas separate but never trail. The output is a value your program can use — and a single mistake anywhere stops the whole parse, which is why precise error positions matter so much.

This page gives that parse a user interface: the input editor marks the failing position with its exact line and column, the output shows the canonical formatted result, the tree view shows the structure the parser produced, and the stat strip quantifies it (lines, bytes, nodes, depth). Because it runs the engine's own JSON.parse, whatever passes or fails here is exactly what your application will see. If the parse fails on something mechanical, JSON Repair fixes trailing commas, single quotes and comments and re-parses; once it succeeds, the JSONPath tester extracts values from the parsed tree.

Common JSON parse errors and what they mean

Every message below comes from the same JSON.parse this tool runs, so the wording matches what you'd see in a browser console or a Node.js stack trace. Paste the payload here and the status bar points at the exact line and column — usually enough to spot the cause immediately.

Common JSON parse errors
Error message	Cause	Fix
Unexpected token	A character appears where a value, comma, colon, or bracket was expected — often a trailing comma, a missing comma between elements, or an unquoted key	Jump to the reported line/column and add or remove the offending punctuation, or click Repair
Unexpected end of JSON input	An opening {, [, or " was never closed — the document is truncated or a bracket is missing	Add the missing closing character, or confirm the full response was pasted
Unexpected string / Unexpected number	A string or number appears where a comma or colon was expected — usually two values sitting next to each other with no separator	Insert the missing comma or colon at the reported position
Trailing comma (e.g. [1, 2,])	JSON forbids a comma before a closing bracket, unlike JavaScript object and array literals	Remove the trailing comma, or click Repair
Single quotes ('key': 'value')	JSON requires double quotes for strings and keys; single quotes are JavaScript-only syntax, not JSON	Replace with double quotes, or click Repair
Comments (// or /* */)	JSON has no comment syntax at all; a // or /* starts a token the parser can't interpret	Remove the comments, or use a JSON5 tool if you need to keep them
NaN / Infinity	JSON has no token for these — only ordinary numbers are valid, so a value a producer computed as NaN or Infinity breaks the parse	Replace with a string, null, or another sentinel value before parsing
BOM (byte-order mark)	Some editors and exports prepend an invisible U+FEFF character before the opening brace, which isn't valid JSON whitespace	Strip the leading character — Repair removes it automatically

Help

Frequently asked questions

Everything you need to know about the JSON Parser.

01What does a JSON parser do?

A parser reads JSON text and converts it into structured data — objects, arrays, strings, numbers, booleans, and nulls. This tool runs the same parse your application would, then shows the result formatted, as a tree, and with statistics, so you know precisely how your data will be interpreted.

02Why does my JSON fail to parse?

The status bar shows the first violation with its line and column. Typical causes: trailing commas, single quotes, unquoted keys, comments, or special values like NaN and undefined that JavaScript allows but JSON forbids. The Repair wrench fixes most of these automatically.

03Is this the same as JSON.parse in JavaScript?

Yes — it literally uses the engine's native JSON.parse, so its acceptance and rejection behavior matches what Node.js and every browser will do with the same input. If it parses here, it parses in production.

04Can I parse and then transform the data?

Yes. After a successful parse you can sort keys, filter to a subpath with a query, or convert the parsed structure to XML, CSV, YAML or an escaped string — all from the same workspace.

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