JSON FormatterBeautify and pretty-print JSON with consistent indentation.Open tool JSON ValidatorCheck JSON syntax and pinpoint the exact error line.Open tool
Both tools parse JSON with the same engine, but they answer different questions. The Formatter takes JSON you already trust and makes it readable; the Validator takes JSON you don't trust and tells you exactly where it breaks. They're two halves of one workflow, not rivals — and everything runs 100% in your browser.
Use the Formatter when
- You have valid JSON that's cramped or minified and you need to read or edit it.
- You want consistent indentation — 2-space, 4-space, or tabs — to match a codebase.
- You want to sort object keys alphabetically so diffs stay stable.
- You're preparing JSON to paste into a file, a commit, or a colleague's editor.
Use the Validator when
- You're not sure the JSON is valid and you want a definitive yes or no.
- Something threw a parse error and you need the exact line and column.
- You want to catch trailing commas, unquoted keys, and single quotes before they bite.
- You want a structure tally and warnings for duplicate keys.
Side by side
| JSON Formatter | JSON Validator | |
|---|---|---|
| Primary job | Make valid JSON readable | Confirm JSON is valid |
| Changes your data? | Re-indents only — data untouched | Never — strictly read-only |
| On invalid input | Reports the error; won't guess a fix | Pinpoints line + column with a caret |
| Output | Pretty-printed JSON | A diagnostics report |
| Sort keys | Yes (optional) | — |
| Duplicate-key warnings | — | Yes |
| Structure tally | — | Yes — objects, arrays, depth… |
| Runs 100% locally | Yes | Yes |
under the hood
They share an engine. Both parse your JSON with the same grammar walker, so a document the Validator calls valid is one the Formatter can always pretty-print — and a large file runs in a background worker in either tool, so the page never freezes.
bottom line
Format to read it, validate to trust it. In practice you reach for both: validate first to catch the error, then format to read the result.