Source
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⌘Enter format · ⌘ShiftEnter validate · ⌘K commands
Developer utility
JSON Formatter & Validator
Format, validate, explore and analyze JSON instantly.
Free toolkit with a JSON formatter, encoder/decoder, encryption utility and JWT parser.
Everything is processed locally in your browser and is never uploaded.
Result
Output
Formatted output will appear here.
Format or validate JSON to explore it as a tree.
Large containers are rendered on demand. A maximum of 500 items is shown per expanded container.
Format or validate JSON to see its structure and size.
Structural comparison
Compare two JSON documents
Whitespace and property formatting are ignored.
Add two valid JSON documents to compare them.
Local code generation
Generate models from your JSON
Types are inferred from the current parsed JSON; review generated code before using it in production.
Format or validate JSON to generate typed models.
Local conversion
JSON → CSV
Works with a top-level array of objects. Nested objects become dotted columns; arrays are kept as JSON inside a cell.
Format or validate a top-level array of objects to convert it.
Local conversion
Encoder / Decoder
Convert text between Base64, Base64URL, percent-encoded URLs, HTML entities, hex and binary, or apply ROT13 and simple text transforms. Everything is computed in your browser.
Ready — choose a transformation and start typing.
Web Crypto, locally
Encryption Utility
Create SHA-2 hashes, HMAC signatures and AES-GCM or AES-CBC ciphertext right here. AES keys are derived from your passphrase with PBKDF2 (150,000 iterations, SHA-256) plus a random salt and IV that travel with the ciphertext.
Ciphertext envelope: v1:salt:iv:data in the selected format.
Ready — choose an operation and enter your text.
Password studio
Strong password & key generator
Random values come from crypto.getRandomValues. Nothing is stored, logged or transmitted — copy what you need before leaving the page.
Choose a length and character set, then generate.
Decode and verify
JWT Parser
Decode the header, payload and signature of a JSON Web Token, inspect its registered claims, and optionally verify HS, RS, PS or ES signatures locally. Tokens are never uploaded.
Not verified
Paste a token, then choose Decode token.
Header
Payload
Registered claims
Signature
About the JSON Formatter
Paste JSON and this tool formats, validates and explores it in one pass. Validation reports the exact line, column and position of a problem together with the surrounding text; the tree view renders huge documents on demand; and the analyzer counts objects, arrays, keys, depth and null values. Because parsing uses the browser's own JSON.parse, no document is ever uploaded — the page keeps working even if you disconnect from the network.
What you can do
- Format with 2 spaces, 4 spaces or tabs, and minify back to a single line.
- Validate with line, column and position plus a snippet of the surrounding text.
- Repair common mistakes — comments, trailing commas, single quotes and byte-order marks — behind an approval preview.
- Explore a collapsible tree with search, JSON path inspection and value copying.
- Analyze structure: container counts, depth, empty containers, largest containers and frequent keys.
- Compare two documents structurally, ignoring whitespace.
- Generate TypeScript, Kotlin, Java or Swift models, or convert an array of objects to CSV.
- Keyboard shortcuts, a command palette and a light or dark interface.
How to use the JSON Formatter
- Paste JSON into the editor, drop a .json file onto it, or load one of the built-in examples.
- Choose Format JSON, Minify or Validate — ⌘Enter formats immediately.
- Open the Tree, Analyze, Diff, Generate Code or JSON → CSV tab to inspect the document further.
- Copy or download the result. Nothing is stored, logged or transmitted.
Keyboard shortcut: press Alt+1 to Alt+4 to move between tools, or ⌘K for the command palette.
Frequently asked questions
- Is my JSON uploaded to a server?
- No. This page is a static HTML shell with no back-end: parsing uses the browser's own JSON.parse and the text stays on your device. You can even disconnect from the network after the page has loaded and keep working.
- How much JSON can it handle?
- Documents up to about 10 MB. Larger inputs are refused so the browser stays responsive, and the structural analysis stops after 250,000 values with a notice that the totals are partial.
- Can it fix invalid JSON?
- It previews safe repairs for the most common problems: JavaScript-style comments, trailing commas, single-quoted strings and a leading byte-order mark. Nothing changes until you accept the preview.
- Does it keep my data between visits?
- No. Only your light or dark theme preference is stored, in localStorage. Pasted JSON is never saved and disappears when you close or reload the tab.
More free developer tools
- Base64, URL & Hex Encoder / Decoder Encode and decode Base64, URL, HTML, hex and binary text instantly.
- Hash, HMAC & AES Encryption Utility Hash, sign and encrypt text locally with the Web Crypto API.
- JWT Decoder & Signature Verifier Decode and verify JSON Web Tokens, claims and signatures.
Every tool on this site runs entirely in your browser. Nothing you paste is uploaded, stored or logged, and no account is required.