JSON Formatter Online — Format and Beautify JSON Instantly
FreePaste raw JSON and get it formatted with syntax highlighting in one click. Validates as it formats. Runs in your browser — nothing uploaded. Free.
What's next
Settings guide
Indentation:
- ·2 spaces — Standard for web and JavaScript projects. Matches Prettier and ESLint defaults.
- ·4 spaces — Common in Python, Java, and C# codebases. Matches most IDE defaults in those languages.
- ·Tabs — Used in Go and some older JavaScript style guides. Tab width is controlled by the viewer's editor.
- ·Compact — Strips all whitespace. Equivalent to minification — use when you need to copy back into a compressed context.
Key sorting:
Alphabetically sort all object keys. Useful for diffing two JSON documents (sorted output eliminates key-order differences), comparing API responses, or producing deterministic output for caching.
Format comparison
Formatter vs JSON editor: A formatter is read-only — it takes JSON in and produces formatted JSON out. A JSON editor lets you modify keys and values interactively in a tree view. Use the formatter when you need to read or share raw JSON fast; use a tree editor when you need to modify the structure.
Online formatter vs VS Code: VS Code's Format Document shortcut (Shift+Alt+F) formats open JSON files. The online formatter works on any JSON string you can paste — copied from a terminal, browser tab, or log viewer — without needing to create a file or open an editor.
How it works
Parse
The input is parsed character-by-character against RFC 8259 rules. Value types — strings, numbers, booleans, null, objects, arrays — are identified. Any syntax violation is caught here with an exact position.
Analyse structure
Nesting depth is tracked for every token. The formatter knows which brackets are balanced and which values belong to which keys before writing a single output character.
Re-serialise
The parsed structure is written back out with your chosen indentation applied at each nesting level. Output is guaranteed-valid JSON, re-parseable by any compliant parser without modification.
Copy and use
Paste the formatted JSON into your IDE, API client, documentation, or share it directly. All data is preserved exactly — no values are rounded, truncated, or modified.
About this format
JSON from APIs, log dashboards, and database exports arrives in the format machines prefer — a single unbroken line with no whitespace. Reading it requires a formatter. Paste your minified or messy JSON and the output is immediately indented with consistent spacing, colour-coded by type, and nested structure made visible at a glance.
The formatter validates as it runs. Syntax errors — trailing commas, unquoted keys, mismatched brackets — are flagged with line and column numbers before any output is produced. This makes it equally useful as a quick validity check and a readability tool.
Common use cases: inspecting a raw API response copied from DevTools, sharing a readable config snippet with a teammate, or cleaning up a JSON blob before pasting it into documentation.