How to Use the JSON Formatter
1. Paste your JSON into the input area on the left 2. Click Format to beautify with proper indentation 3. Click Minify to compress into a single line 4. Copy the result using the copy button
Understanding JSON Syntax
JSON (JavaScript Object Notation) is a lightweight data interchange format. Valid JSON must follow these rules:
- Objects are wrapped in curly braces
{} - Arrays are wrapped in square brackets
[] - Keys must be strings in double quotes
- Values can be strings, numbers, booleans, null, objects, or arrays
- No trailing commas after the last element
Common Use Cases
- API Development: Format API responses for debugging
- Configuration Files: Validate config.json files before deployment
- Data Migration: Clean up JSON exports from databases
- Code Review: Make JSON payloads readable in pull requests
One Parser, Many Outputs
Everything on these pages runs through the same step: parse the text into a real data structure, then render that structure in the shape you asked for. That is why the validator and the converters agree with each other — a document that will not parse cannot be converted, and the error you get is the parse error rather than a silent half-result.
It also means formatting is not cosmetic. Re-printing JSON proves it parsed.
What JSON Does Not Have
Most JSON problems come from expecting a type it never defined:
| Missing | What people do instead | Cost |
|---|---|---|
| Dates | ISO 8601 strings | Every consumer must parse them |
| Integers vs floats | One number type | 1.0 and 1 are the same value |
| Big integers | number is IEEE-754 double | Precision lost above 2⁵³ |
| Binary | Base64 strings | 33% size increase |
| Comments | Nothing | Config formats add them non-standardly |
| Trailing commas | Nothing | The single most common syntax error |
9007199254740993 parses
as 9007199254740992. Send large IDs as strings.Choosing a Converter
To another data format — [CSV](/dev/json-formatter/json-to-csv), [YAML](/dev/json-formatter/json-to-yaml), [XML](/dev/json-formatter/json-to-xml) — and back again with [CSV to JSON](/dev/json-formatter/csv-to-json), [YAML to JSON](/dev/json-formatter/yaml-to-json) and [XML to JSON](/dev/json-formatter/xml-to-json). None of these round-trips perfectly, because the formats do not have the same expressive power: CSV is flat and typeless, XML distinguishes attributes from elements, and YAML has anchors and multiple documents.
To type definitions — [TypeScript](/dev/json-formatter/json-to-typescript-converter),
[Go](/dev/json-formatter/json-to-go), [Python](/dev/json-formatter/json-to-python),
[Java](/dev/json-formatter/json-to-java-class), [C#](/dev/json-formatter/json-to-csharp),
[Kotlin](/dev/json-formatter/json-to-kotlin), [Swift](/dev/json-formatter/json-to-swift),
[Ruby](/dev/json-formatter/json-to-ruby-hash) and
[PHP](/dev/json-formatter/json-to-php-array). Generated types are a starting point, not an
answer: a sample cannot tell the generator which fields are optional, which strings are
enums, or which null means "absent" rather than "empty".
To inspect — [validate](/dev/json-formatter/json-validator), [diff](/dev/json-formatter/json-diff-tool), [query by path](/dev/json-formatter/json-path-finder), [check against a schema](/dev/json-formatter/json-schema-validator), [sort keys](/dev/json-formatter/json-sorter) or [flatten](/dev/json-formatter/json-flattener).
Sorting Keys Makes Diffs Readable
JSON objects are unordered by specification, but the *text* has an order, and a diff sees text. Two serialisers that emit the same data in different key orders produce a diff touching every line.
Sorting keys before committing any JSON to version control — lockfiles, fixtures, exported config — turns those diffs into the two lines that actually changed. It is also the cheapest way to compare two API responses that should be equivalent.
Minify for Transport, Format for Humans
Whitespace is typically 10–30% of a JSON payload and compresses extremely well, so gzip or brotli recovers most of the difference. Minify what you send over the wire; keep the formatted version in your editor and your repository, where a readable diff is worth far more than the bytes.
Everything Runs Locally
Documents are parsed in your browser and never uploaded. That matters here more than for most tools: the JSON people most want to inspect is usually an API response containing someone's data.