How to format and validate JSON
This tool does the three things you most often need from raw JSON: it beautifies messy or minified text into clean, indented structure, it validates that the document is well-formed, and it minifies valid JSON down to the smallest byte count. Pick a mode with the toggle, paste your data into the left pane (or drag a .json file in), and press Run. The formatted result appears on the right, ready to copy or download. There is no upload, no queue and no account — every step is a local JavaScript operation that finishes in milliseconds.
In Beautify mode you choose the indentation that matches your codebase: two spaces, four spaces, or a real tab character. An optional Sort keys switch reorders every object's keys alphabetically and recursively, which is invaluable when you want two JSON documents to line up for a visual or git diff. Because the ordering rule is explicit, the same input always produces byte-identical output — exactly what you want when the result feeds a pipeline, a snapshot test, or a code review.
Pinpoint errors by line and column
The most frustrating part of hand-editing JSON is a single misplaced comma or unclosed bracket buried in thousands of lines. When parsing fails, this validator does not just say "invalid" — it surfaces the underlying parser message and translates the character offset into a human line and column, so you can jump straight to the problem. Common culprits it catches include trailing commas, single quotes instead of double quotes, unquoted keys, missing commas between members, and stray control characters pasted from a rich-text source.
Validation is strict by design. JSON is a small, precise format, and a tool that "helpfully" accepts almost-JSON would let real bugs through to whatever consumes the data next. By holding to the specification exactly, the validator gives you a trustworthy yes-or-no answer: if it formats cleanly here, a conforming parser elsewhere will accept it too.
Beautify vs minify — when to use each
The two directions solve opposite problems. Beautify is for humans: you expand the structure so it can be read, reviewed and debugged. Minify is for machines and transport: it strips every optional space and newline to shrink the payload, which matters for API request bodies, embedded configuration, cache values and anywhere bytes cost money or latency. The tool reports how much smaller the minified output is so you can see the saving at a glance. Whichever way you go, the content is never altered — only the whitespace changes — so a beautified document and its minified twin parse to the exact same value.
Why a local formatter beats pasting into an AI
It is tempting to drop a blob of JSON into a chatbot and ask it to "clean this up." For throwaway sample data that is fine. For anything real it is a poor idea on two fronts. First, privacy: API responses, configuration files, customer records and tokens routinely live inside JSON, and that content should not be transmitted to a third-party model that may retain or train on it. Once data leaves your machine you have lost control of it. Second, correctness: a language model can silently reorder members, drop a deeply nested field, or "fix" a value in a way that changes meaning. A real parser does none of that — it round-trips your document through the browser's native JSON engine and changes nothing but layout.
gitime.dev is built around this distinction. Generating a one-off snippet is something AI does well. Processing your actual data — parsing, validating, formatting, minifying — is work that belongs in a deterministic tool that runs where the data already lives: your browser tab. Nothing here phones home, so you can format a config full of secrets without it ever touching a server.
Working with large files
Skipping the upload step is also a speed win. There is no round-trip to a server and no file-size cap imposed by an API, so multi-megabyte documents format about as fast as your CPU can parse them. Drag a .json file straight onto the input area and the tool reads it locally; the output panel then reports the result size and the nesting depth of the document so you have a quick sense of its shape.
- Indentation is configurable: 2 spaces, 4 spaces, or tab.
- Key sorting is recursive and alphabetical, ideal for diff-friendly output.
- Errors are reported with line and column, not a vague failure.
- Minify reports the percentage size reduction.
- Everything stays on your device — no upload, no logging of input content.
Frequently asked questions
- Is my JSON uploaded to a server?
- No. Everything runs as JavaScript inside your browser. Your JSON is never sent over the network, which makes the tool safe for sensitive or proprietary data.
- How does it report errors?
- On a parse failure it shows the parser message plus the 1-based line and column of the problem, so you can fix the exact bracket, comma or quote.
- What is the difference between beautify and minify?
- Beautify adds readable indentation; minify removes all optional whitespace to produce the smallest valid JSON. The content is identical either way.
- Does it support large files?
- Yes. With no upload step, large files format quickly. Drag and drop a
.jsonfile directly onto the input.