Developer tools / JSON
JSON Formatter
Turn dense JSON into readable data, catch syntax errors, or minify it for delivery. Everything stays in this tab.
Input and result
Paste, choose your format, then copy or save.
Paste JSON or open a local .json file.
Format, validate, sort keys, or minify the data.
Copy the result or download a clean JSON file.
Practical guide
Format, validate, sort, or minify JSON offline
Paste JSON to make nested data readable, validate its syntax, sort object keys, or create compact output. Processing stays in the browser, which is useful for configuration fragments and API samples that should not be sent to a third-party formatter.
Common uses
- Locate a syntax error in an API response or configuration file.
- Normalize indentation before a code review or documentation update.
- Minify JSON for a fixture, request body, or embedded example.
What to expect
- Validation
- Invalid input produces an actionable parse error instead of silently changing the value.
- Formatting
- Choose indentation and optionally sort keys without changing array order.
- Export
- Copy the result or download a local JSON file after validation succeeds.
Try a concrete example
- Input and settings
- Paste {"z":2,"a":1}, enable Sort object keys, and select Format JSON.
- Expected result
- An indented object with "a" before "z". Copy that sorted result into the input before selecting Minify to get {"a":1,"z":2}. Array order stays unchanged.
Limits and alternatives
Comments, trailing commas, and single-quoted keys are not valid JSON. This formatter uses JavaScript numbers: integers beyond Number.MAX_SAFE_INTEGER can lose precision. Represent large identifiers as quoted strings before processing. Duplicate object keys are reduced to their last value by JSON parsing.
Follow a worked example
Compare an invalid example with corrected JSON, then format, sort, and download it.