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JSON Formatter

Paste JSON to pretty-print or minify it, validate strict JSON syntax and inspect parse errors directly in your browser.

TOOLMERA / DEVELOPER
JSON Formatter
Browser-first processing
Privacy-mindedBrowser-first whenever possible
Instant workflowNo setup or account required
Free core toolOpen it and get the task done
WHY TOOLMERA

Built to get the task done.

  • Format & minify
  • Syntax validation
  • Indentation controls
ABOUT THIS TOOL

JSON Formatter & Validator — Beautify & Minify

Format, validate and minify JSON locally with selectable indentation, clear parse errors and no Toolmera server upload.

JSON syntax validation and common errors

Valid JSON follows strict syntax rules. Property names and string values use double quotes, trailing commas are invalid, and comments are not part of standard JSON. Toolmera validates input with the browser’s JSON.parse implementation.

When the browser error message includes a character position, Toolmera also derives a line and column to make the problem easier to locate. The tool reports malformed JSON; it does not automatically repair it.

Valid key"name": "Toolmera"
Invalid keyname: 'Toolmera'
Trailing commaInvalid in standard JSON
CommentsInvalid in standard JSON

Pretty print vs. minify

Pretty printing adds indentation and line breaks so nested objects and arrays are easier to inspect. Toolmera supports 2-space, 4-space and tab indentation.

Minifying removes optional whitespace to create a compact JSON string. Both operations parse the JSON first, so malformed input produces a validation error instead of a misleading reformatted result.

HOW IT WORKS

How to use JSON Formatter

01

Paste your JSON

Enter or paste the JSON payload you want to inspect.

02

Format or minify

Validate the syntax and choose the output formatting you need.

03

Copy the result

Copy the formatted or minified JSON into your next workflow.

SOURCES

Reference material used for this page:

RFC 8259 — The JavaScript Object Notation (JSON) Data Interchange Format
NEXT STEP

Continue your workflow

encode a text payload as Base64
KEEP GOING

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FAQ

Common questions

Does Toolmera repair invalid JSON?

No. It validates with JSON.parse and reports the parse error. You must correct malformed JSON before it can be formatted or minified.

Can I choose the indentation style?

Yes. The formatter supports 2 spaces, 4 spaces or tabs.

Why are trailing commas rejected?

Trailing commas are not valid in standard JSON, even though some programming-language object syntaxes allow them.

Is JSON processed locally?

Yes. The formatter, validator and minifier run in the browser and do not send the pasted JSON to a Toolmera processing server.