JSON Viewer
Paste JSON to validate it and explore the structure as a collapsible tree or formatted JSON.
JSON → structure
JSON
Parsed
id: 1
name: Alice Johnson
0: admin
1: editor
city: San Francisco
state: CA
zip: 94102
theme: dark
notifications: true
Valid JSON · 1 key · runs locally
What this tool does
Paste a JSON document and this viewer parses it into a structure you can explore — expand and collapse the tree to inspect nested objects and arrays, or switch to the JSON view for a pretty-printed equivalent. It validates as you type and underlines the line where parsing fails, which is usually all you need to spot the stray comma in an API response or config file. Everything runs in your browser.
How to use it
- Paste your JSON into the left pane — or hit Upload to open a
.jsonfile from your machine. - Watch it parse live. The status bar turns green when the document is valid, or names the failing line when it isn't — and the editor underlines it.
- Explore the Tree — click any node to collapse it — or switch to JSON for the pretty-printed equivalent.
- Copy JSON, or open the Download menu to save it formatted or minified.
Frequently asked questions
Is my JSON uploaded anywhere?
No. Parsing runs entirely in your browser. Nothing is sent to a server, logged, or stored.
How large a document can it handle?
Comfortably into the megabytes — parsing is native JSON.parse, and the tree renders collapsed beyond three levels deep, so even a large API response stays responsive. Very deep expansion of a huge document is where browsers eventually slow down.
What happens when the JSON is invalid?
The status bar turns red and names the failing line along with the reason — a trailing comma, an unquoted key, a missing bracket — and the same line is underlined in the editor so you can jump straight to it.
Does it accept comments or trailing commas?
No — this viewer is strict JSON, per the spec. JSON5/JSONC conveniences like comments, trailing commas, and unquoted keys are reported as errors, which makes it a reliable check that a document will parse anywhere
JSON.parse does.Can I reformat the JSON?
Yes. The JSON view shows it pretty-printed with 2-space indentation, Copy JSON copies that formatted version, and the Download menu offers both formatted and minified files.