The JSON viewer built for reading data, not fighting a wall of text
Paste, drop, or upload any JSON and get an instant, searchable tree — plus formatting, validation with exact error location, and one-click export to CSV or TypeScript.
Press ? anytime for keyboard shortcuts.
Everything a JSON tool should have done from the start
Built to fix the slow, cluttered, ad-choked tools most people land on when they search “json viewer online.”
Interactive tree view
Collapse, expand, and scan deeply nested objects and arrays without losing your place, with counts on every branch.
Precise validation
Invalid JSON? Get the exact line and column of the first error, in plain English — not a cryptic parser dump.
Instant search
Filter huge payloads down to the keys and values you care about; matching branches expand automatically.
CSV & TypeScript export
Turn an array of records into a spreadsheet, or generate a TypeScript interface straight from the shape of your data.
Shareable links
Encode small JSON snippets directly into a URL so a teammate can open the exact same view — no pasting required.
Private by design
Formatting and validation run locally in JavaScript. Nothing you paste is uploaded, logged, or stored on a server.
Autosave drafts
Your last input is kept in your browser's local storage so a refresh never costs you your work.
Dark & light themes
Easy on the eyes in a late-night debugging session, or crisp and printable during the day.
Keyboard-first
Format, minify, search, and navigate without reaching for the mouse — full shortcut list built in.
How to format and validate JSON online
Add your JSON
Paste text, drag a .json file onto the input, or click Upload to browse for one.
Format or validate
Click Format to pretty-print with your chosen indent, or Validate to check syntax without changing anything.
Explore and export
Browse the tree, search inside it, then copy, download, or export to CSV / TypeScript.
About JSON
JSON (JavaScript Object Notation) is a lightweight, text-based format for representing structured data. It grew out of JavaScript's object syntax but is now language-independent — nearly every programming language has a JSON parser, which is why it has become the default format for web APIs, configuration files, and data interchange between services.
The building blocks of JSON
A JSON document is built from just six things:
{ "key": value, ... }
array → [ value, value, ... ]
string → "text in double quotes"
number → 42, -3.14, 2.5e10
boolean → true or false
null → nullObjects hold key–value pairs where keys are always strings; arrays hold ordered lists of values. Either can nest inside the other to any depth, which is how JSON represents complex, real-world data with just those six primitives.
JSON vs. XML
Before JSON became standard, XML was the common choice for data interchange. JSON won out for API payloads because it maps directly onto native data structures in most languages (objects and arrays), has far less syntactic overhead than XML's opening/closing tags, and is easier for both humans and machines to scan quickly.
Common JSON errors and how to fix them
| Error | Cause | Fix |
|---|---|---|
| Unexpected token | A trailing comma before } or ] | Remove the comma after the last item |
| Unexpected string | Missing comma between two key–value pairs | Add a comma between entries |
| Unexpected end of JSON input | An unclosed brace, bracket, or quote | Check every opening symbol has a matching close |
| Bad control character | A raw newline or tab inside a string | Escape it as \n or \t |
| Unexpected token ' | Single quotes used instead of double quotes | JSON strings and keys must use "double quotes" |
This tool's Validate button surfaces the exact line and column for the first issue it finds, so you don't have to scan the whole document by eye.
Frequently asked questions
Yes. Every feature — formatting, validation, tree view, search, and CSV/TypeScript export — is free with no sign-up required.
No. Parsing, formatting, and validation all run locally in your browser with JavaScript. Your data never leaves your device unless you use the share-link feature, which encodes the data inside the URL itself.
Click Validate. If the JSON is invalid, the tool shows the exact line and column of the first syntax error along with a plain-language reason, such as a missing comma, an unescaped quote, or a trailing comma before a closing brace.
Yes. Use the Export dropdown to download an array of objects as a CSV spreadsheet, or generate a TypeScript interface definition straight from your JSON's shape.
The tool comfortably handles files up into the tens of megabytes since everything runs in your browser's memory. Very large arrays are automatically collapsed by default in the tree view to keep scrolling smooth.
Yes. Typing in the search box filters the tree to matching keys and values, automatically expanding parent nodes so results are never hidden inside a collapsed branch.