JSON Formatter & Validator
Beautify, minify and validate JSON with clear error messages.
Updated: June 26, 2026
Format, minify and validate JSON
Paste raw JSON and instantly beautify it with consistent indentation, collapse it to a single line for transport, or validate it and get a clear error message when something is off. Everything runs in your browser using the native JSON parser, so your data never leaves your machine — safe for API payloads and config you'd rather not paste into a random server.
Beautify vs minify
Beautify (pretty-print) adds line breaks and indentation so a dense object becomes readable — ideal when you're debugging an API response or reviewing a config file. Minify strips every unnecessary space and newline, producing the smallest valid representation, which is what you want for sending over the network or embedding in another file. Both produce exactly the same data; only the whitespace differs.
Why validation matters
A single trailing comma, a missing quote, or a stray comment will make a parser reject the whole document — and the resulting error can be cryptic. This tool reports the failure clearly so you can jump to the problem. Remember JSON's strict rules: keys and strings must use double quotes, no trailing commas are allowed, and comments are not part of the spec.
Common JSON mistakes
- Trailing comma after the last item in an object or array.
- Single quotes instead of double quotes around keys or strings.
- Unquoted keys (valid in JavaScript objects, invalid in JSON).
NaN,Infinityorundefined, which JSON does not support.- Comments — JSON has none; strip them before parsing.
Privacy and related tools
Because formatting happens client-side, you can safely beautify sensitive payloads. If your data is in YAML instead, convert it with the YAML ↔ JSON converter; to inspect a token's JSON claims, use the JWT decoder; and to search structured text, try the regex tester.
Frequently asked questions
Is my JSON uploaded anywhere?
No. Formatting, minifying and validation all run in your browser with the native JSON parser. Nothing is sent to a server, so it's safe for sensitive data.
Why is my JSON invalid when it looks fine?
The most common causes are a trailing comma, single quotes instead of double quotes, unquoted keys, or comments — none of which are allowed in strict JSON.
What's the difference between beautify and minify?
Beautify adds indentation and line breaks for readability; minify removes all unnecessary whitespace for the smallest size. The underlying data is identical.
Does formatting change my data?
No. Only whitespace changes. Key order is preserved and values are untouched, so the parsed result is exactly the same.
API development tools
If you work with JSON APIs all day, these speed up the workflow:
- API client / testing platform Send requests, inspect formatted responses and save collections instead of pasting JSON back and forth.
- Schema validation library Enforce JSON structure with JSON Schema so malformed payloads are caught before they reach your code.
Learn more
- Cron Syntax Cheat Sheet: How to Read Cron Expressions Stop guessing what a cron line does. A quick, practical reference to the five fields, the special characters, and the schedules you'll actually write.
- JSON vs YAML: When to Use Each JSON and YAML describe the same data in very different styles. Here's how they compare, the YAML traps to watch for, and which to reach for when.
- Regex Basics: A Beginner's Guide to Regular Expressions Regular expressions look like line noise until you learn the handful of building blocks. Here's the beginner's path, with examples you can test as you go.
Related tools
- YAML ↔ JSON ConverterConvert YAML to JSON and back, with clear parse errors.
- Regex TesterTest regular expressions against text and inspect every match and group.
- JWT Decoder & ValidatorDecode a JWT's header and payload, inspect its claims, and verify an HS256 signature.
- Cron Expression ExplainerDecode any cron schedule into plain English and preview the next run times.