JSON Viewer &
Formatter
Paste JSON to format, validate, and explore with syntax highlighting. Prettify or minify instantly in your browser.
Formatted output will appear here...
How It Works
Paste JSON
Paste any JSON string into the input area.
Format & Explore
Instantly see formatted, syntax-highlighted output.
Copy or Minify
Copy the prettified or minified version to clipboard.
Format and validate JSON online with syntax highlighting, expandable trees, and instant error reporting. ConverterUp's JSON viewer is built for backend developers, API consumers, and data analysts who need to inspect responses, beautify minified payloads, or quickly minify JSON before pasting it into a config file. Drop a file or paste the text, expand and collapse nested objects, and copy the prettified or compact result. The JSON is parsed locally in your browser, so private API responses, tokens, and customer data never reach a remote server.
Frequently asked questions
How are JSON errors reported?
Invalid JSON is highlighted at the exact line and column where the parser failed, with a short description such as unexpected token or trailing comma. Fix the issue and the tree view updates automatically.
What is the maximum JSON size?
Files up to 25 MB parse smoothly on most laptops. Above that, the tree view may become slow because the browser has to render thousands of nodes. Use minify mode for very large payloads.
Does it support JSON5 or comments?
No. The viewer enforces strict JSON per RFC 8259, so trailing commas, single quotes, and comments are flagged as errors. Use a JSON5 converter first if you need that flexibility.
Is my JSON sent to a server?
No. Parsing, formatting, and minification all run client-side. ConverterUp has no logging endpoint for JSON content, which is critical when debugging payloads with credentials or PII.