What is a JSON formatter?
A JSON formatter adds consistent indentation and line breaks so compact or irregular JSON is easier to read and edit.
JSON Formatter & Editor
Format, edit, validate, minify and view JSON online. Free browser-based JSON editor with syntax highlighting and tree view. No sign-up required.
About the JSON Formatter & Editor
Format, edit, validate, minify and inspect JSON for APIs, configuration files and structured data. The syntax-highlighted editor preserves large integers, while the expandable tree view makes nested objects and arrays easier to explore. Processing stays in your browser.
- Precision-safe JSON formatting
- Expandable JSON tree viewer
- Line-aware syntax validation
- JSON minification and downloads
How to use the JSON Formatter & Editor
- Paste JSON or upload a .json file.
- Choose indentation, then format, minify or validate the document.
- Inspect nested data in Tree view, then copy or download the result.
Frequently Asked Questions
Can I validate JSON syntax?
Yes. Validate reports malformed JSON with line and column details when available.
Can I view JSON as a tree?
Yes. After formatting or validating valid JSON, switch to Tree view to explore nested objects and arrays.
Does formatting change large integers?
No. DevMaster Tools uses a lossless JSON number representation so integers beyond JavaScript's safe range are not silently rounded.
Is my JSON uploaded to a server?
No. Parsing, validation and formatting happen entirely in your browser.