JSON Tools
One toolkit for the JSON work that fills a normal day — reading an API response, checking why a config was rejected, shrinking a payload, working out what changed between two documents. Every tool runs entirely in your browser: nothing is uploaded, nothing is stored.
JSON tools
JSON Formatter
Paste JSON and pretty print it with 2, 3 or 4 space indentation, syntax highlighting and a collapsible tree. Fast, private and 100% in your browser.
Open JSON FormatterJSON Validator
Validate JSON and inspect the exact line and column of syntax errors. Auto-fix trailing commas, unquoted keys, and single quotes instantly.
Open JSON ValidatorJSON Minifier
Minify JSON by removing unnecessary whitespace and line breaks. See compression stats and copy the smallest valid payload.
Open JSON MinifierJSON Diff
Compare two JSON documents side by side and see added, removed and changed values highlighted key by key.
Open JSON DiffConverters
JSON to TypeScript
Instantly generate TypeScript types and interfaces from JSON payloads. Handles nested objects, arrays, and unions. Free and private.
Open JSON to TypeScriptJSON to YAML
Convert JSON to clean, readable YAML instantly. Supports nested objects, arrays, and multiline strings in your browser.
Open JSON to YAMLJSON to CSV
Convert JSON arrays and objects to CSV format online. Export directly to Excel, Google Sheets, or copy to clipboard.
Open JSON to CSVJSON to TOML
Convert JSON documents into TOML configuration files online. Free, secure, and runs locally without server uploads.
Open JSON to TOMLDeveloper tools
JSONPath Tester
Write a JSONPath expression and see every matching value and path in your document as you type. Real-time and local.
Open JSONPath TesterJSON Schema Validator
Check a JSON document against a JSON Schema and get a readable list of every constraint it violates in real time.
Open JSON Schema ValidatorWhat each tool is for
The formatter workspace on the home page covers the three jobs most people arrive for.Formatting re-indents JSON with 2, 3 or 4 spaces, colour-codes every value type and gives you a collapsible tree for structures too deep to read as text.Validation runs on the same pass and reports the exact line and column that broke the parse, in plain English rather than a bare "invalid JSON".Minifying goes the other way, stripping every space and newline so the payload is as small as it can be while staying valid.
The three developer tools each get their own two-panel page, because each one needs two inputs.JSON Diff takes two documents and reports what was added, removed and changed, path by path. JSONPath Tester takes a document and an expression and lists every match as you type. JSON Schema Validatortakes a document and a schema and tells you exactly which constraints failed and where.
The formatter workspace also converts JSON to CSV, YAML and XML, generates TypeScript interfaces from a sample payload, searches keys and values, and copies the dot-notation path to any value. A command palette on ⌘K reaches all of it from the keyboard.
Why browser-only matters
Most free JSON utilities post your input to a server to do the work. That is a real problem when the thing you are debugging holds access tokens, customer records or internal endpoints. Every tool listed here parses JSON with the browser's own engine, so there is no upload step, no request in the network tab and no server-side log. You can safely paste a production response without routing your company's data through somebody else's infrastructure.
Open the JSON formatter — or browse the sample documents if you want something to try it on.