Tools
JSON formatter & validator
Paste messy or minified JSON and get it back clean. Pretty-print with two-space indentation, minify to the smallest valid form, sort keys for stable diffs, and validate as you type, with the exact parser error and an approximate line and column when something is off. Everything runs locally in your browser, so nothing you paste ever leaves the page.
Paste or type JSON. Validation runs as you type, and nothing is uploaded.
A JSON tool that never phones home
Most online JSON formatters send your payload to a server to process it. That is a problem when the JSON is a webhook body, an auth response, or a config file full of secrets. This one uses the browser's native JSON.parse and JSON.stringify, with no network calls, no analytics on your data, no exceptions. Close the tab and it is gone.
Frequently asked questions
- Is my JSON uploaded anywhere?
- No. The formatter runs entirely in your browser using native JavaScript. Your data never leaves the page, is never sent to a server, and is not logged, so it is safe for payloads that contain tokens, keys, or customer data.
- How does the validator find errors?
- It parses your text with the browser’s built-in JSON engine and surfaces the exact parser message. When the engine reports a character offset or line and column, we translate it into an approximate line and column so you can jump straight to the problem.
- What does "sort keys" do?
- It recursively reorders every object’s keys alphabetically before formatting. That gives you a stable, diff-friendly output, handy for comparing two API responses or committing config files where key order should not matter.
- Why show byte size before and after minifying?
- Minifying strips whitespace, which is often the cheapest way to shrink an API response or config blob. Seeing the before and after byte count tells you exactly how much you saved before shipping it over the wire.
- Is there a size limit?
- Input is capped at about 15 MB so parsing stays instant and your browser tab stays responsive. Most API responses and config files are a few kilobytes, well under the limit.