JSON Formatter & Validator
Paste raw JSON to beautify it, minify it or find out precisely where it breaks — with the failing line, column and character reported.
About the JSON Formatter & Validator
JSON arrives unreadable more often than not. An API returns a single line four thousand characters long, a log entry contains a nested object flattened into one string, and a configuration file has been hand-edited until a comma is either missing or one too many. The parser's response is famously unhelpful: Unexpected token } in JSON at position 1847 tells you almost nothing about where in the structure the problem is.
This formatter does two jobs. It pretty-prints valid JSON with consistent indentation so the structure becomes visible, and when the JSON is invalid it converts the parser's character offset into a line and column, shows the surrounding text, and points at the exact character that broke it. That turns a hunt through four thousand characters into a two-second fix.
It also minifies, which is the reverse operation: strip every unnecessary space and newline to get the smallest valid payload. That matters when JSON is being embedded in a page, stored in a database column, or sent over a connection where every byte counts. Because everything runs in your browser, you can safely paste a real API response — the kind that contains bearer tokens, internal IDs and customer email addresses — without it being transmitted to anyone.
How to use it
- Paste your JSONDrop in an API response, a config file or a log fragment. Size is not a problem — several megabytes parse comfortably.
- Choose an actionBeautify to make it readable, minify to make it small, or validate to check it without changing anything.
- Set your indentationTwo spaces, four spaces or tabs, matching whatever convention your project uses.
- Read any error preciselyIf parsing fails you get the line, column, character offset and a snippet with the offending character marked.
- Inspect the summaryValid JSON is summarised by type, key count, maximum nesting depth and array sizes.
- Copy or downloadTake the formatted output to your clipboard or save it as a .json file.
Features
- Precise error locationCharacter offsets are converted into a line and column with the surrounding context displayed.
- Beautify and minifySwitch between human-readable and byte-minimal representations of the same data.
- Configurable indentationTwo spaces, four spaces or tab characters.
- Structure summaryRoot type, total keys, nesting depth and array lengths reported for valid documents.
- Key sortingOptionally sort object keys alphabetically to make two versions of a document easy to compare.
- Never transmittedParsing happens in your browser, so production payloads containing secrets stay on your machine.
Who uses this tool
- API developersMake a response readable while debugging, and confirm a request body is valid before sending it.
- DevOps engineersValidate configuration files, Kubernetes manifests exported as JSON and CI pipeline definitions before they are deployed.
- Data analystsUnderstand the shape of an unfamiliar JSON export before writing code that parses it.
- Students and learnersSee how nesting works visually while learning JSON, with immediate feedback on syntax mistakes.
Tips worth knowing
- JSON does not allow trailing commas, single quotes around strings, comments, or unquoted keys — those four mistakes cause most parse failures.
- If a value is a JSON string that itself contains JSON, unescape it and format it separately; double-encoded JSON is a very common source of confusion.
- Sort keys before comparing two configuration files — it turns a noisy diff into a meaningful one.
Frequently asked questions
Why does my JSON say “unexpected token” when it looks fine?
The four usual culprits are a trailing comma after the last item, single quotes instead of double quotes, an unquoted key, or a JavaScript-style comment. All are legal JavaScript and none are legal JSON. The error panel here shows the line and column so you can see which one it is.
Is my data sent to a server?
No. Parsing uses the browser's built-in JSON engine inside your tab. Nothing is uploaded or logged, which is what makes it safe to paste a real response containing access tokens or personal data.
What is the maximum size I can format?
There is no hard limit. Documents of a few megabytes format almost instantly. Very large files — tens of megabytes — are limited by your browser's memory rather than by the tool.
What is the difference between beautifying and minifying?
They produce identical data with different whitespace. Beautified JSON is indented for humans; minified JSON strips every optional space and newline for the smallest possible payload. Parsers treat both exactly the same.
Can it fix invalid JSON automatically?
No, and deliberately so. Guessing at intent could silently change your data — a repair that turns a missing brace into the wrong structure is worse than an error. The tool tells you exactly where the problem is and leaves the decision to you.
Does it support JSON Lines or NDJSON?
Those formats are one JSON document per line, so paste a single line at a time to validate it. A whole NDJSON file will fail as one document because multiple top-level values are not valid JSON.