Developer Tools
JSON Formatter and Validator
Runs locally, which matters when the JSON contains an API response you should not be pasting elsewhere.
- Runs in your browser
- Nothing uploaded
The tool
Paste JSON to format or minify it. Invalid input reports the parse error.
Everything you enter stays on your own machine. Nothing is sent to us or to anyone else, which you can confirm in your browser network tab.
What people use it for
- Making an unreadable API response legible
- Finding the trailing comma breaking a config file
- Minifying JSON before embedding it in a page
- Validating a payload before sending it
- Formatting structured data markup while debugging it
About this tool
Formatting and validating
Formatted output indents with two spaces, which is the common convention and keeps nesting readable. Minified output strips every unnecessary character, which is what you want before sending JSON over a network.
If the input will not parse, the tool shows the JSON parser error exactly as it came. Those messages are terse, but they name the position of the problem, which is usually enough to find a trailing comma or an unquoted key.
Why local matters here
JSON under debugging is very often an API response, and API responses very often carry tokens, personal data or commercial information. Pasting that into a website that processes it server-side hands it to someone else. This tool parses in your browser and makes no request.
Reading a parse error
The message names the position where parsing failed, which usually sits just after the real mistake rather than on it. A complaint about an unexpected character at position four hundred normally means something earlier never closed.
The usual culprits: a trailing comma before a closing brace, a key without quotes, and a single quote where JSON requires a double.
Need this handled across a whole website? See our Backend Web Development and Custom Web Apps page.
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If you would rather someone did this properly for you, we offer Web Design Services and Website Development, SEO Services: Search Engine Optimization, AI Automation Agency.
Questions
Questions about this tool
The things clients actually want to know — costs, timelines, ownership and what happens after launch.
No. Your browser parses it with the built-in JSON parser and makes no request.
Editors often allow comments and trailing commas. Strict JSON allows neither, and this uses the strict parser.
Up to a generous cap. A command line tool suits very large payloads better.
Yes, parsing and re-serialising preserves the original order of keys.
Two spaces, which is the most common convention for JSON.
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