JSON Formatter & Validator

How to use

1. Open this page on any device — no signup needed.
2. Fill in the fields above.
3. Get your result instantly — nothing is uploaded.

About this tool

A JSON formatter re-indents minified JSON into a readable tree, or compresses pretty JSON for production payloads. The validator pinpoints syntax errors (missing commas, unquoted keys, trailing commas) with line and column. APIs, configs and log files are full of JSON — this tool handles them without uploading data anywhere.

Beautify, Minify, and Pinpoint the Error (2026 Guide)

This page is the JSON formatter for people who need the error's exact character, not just "invalid JSON". Paste anything: beautify re-indents it into a readable tree, minify strips it to one wire-sized line, and the validator pinpoints syntax errors by line and column. Below is what each mode actually does to the same payload, plus the five errors you will hit most and the character that causes each.

The same data, three shapes

Take a minified API response like {"user":{"name":"Ali","roles":["admin","dev"],"active":true},"page":2} — beautify turns it into a 2-space indented tree where the roles array is visible at a glance and minify strips it back to a single line. The data never changes; only whitespace does. That is the whole job: pretty for humans reading it, minified for machines shipping it, and identical bytes of information either way.

The five errors this validator sees most

For the trailing-comma case, {"name":"Ali","age":25,}, modern browsers stop at position 22 — "Expected double-quoted property name in JSON at position 22" — which is exactly the character after the comma. The validator converts that position into line and column so a 5,000-line config points at the offending line instead of a needle-in-haystack hunt. Fixing configs by hand pairs well with running the result through the AES encrypt/decrypt tool when the payload also carries secrets, and checking diff side-effects with the text diff checker before and after a mass reformat.

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