Developer & Text · JSON Formatter
Format, minify and validate JSON on your computer
Quick answer
Paste JSON into Toolfox → JSON Formatter (or open a file up to 50 MB). It pretty-prints or minifies instantly, can sort keys, and points to the exact line and column of any error. Numbers are kept exactly as written. It runs entirely on your computer (Mac, Windows or Linux). Files are never uploaded.
How to do it
- Open JSON Formatter and paste JSON or open a file.
- Choose Format, Minify or Validate.
- Read errors with line and column, e.g. “Trailing commas aren't allowed”.
- Copy the result or Save it.
Options you can set
- Indent
- Sort keys
Good to know
- Numbers are kept exactly as written, with no rounding of large or precise values.
- Everything stays on your computer; nothing you paste is stored.
JSON Formatter FAQ
Is it safe to paste API keys or private JSON?
Yes. Nothing leaves your computer and nothing you paste is stored.
Will big numbers lose precision?
No. Toolfox keeps every number exactly as written.
Is JSON Formatter in Toolfox free?
Yes. JSON Formatter is one of 57 tools in Toolfox, a free app for Mac, Windows and Linux with no account, ads, limits or watermarks.
Does JSON Formatter upload my files?
No. Toolfox processes files on your own computer and works offline; your files are never uploaded.
More developer & text tools in Toolfox
Get JSON Formatter and 19 more tools.
Free forever. No account. Works offline. For macOS, Windows and Linux.
Updated 2026-10-18 · Toolfox v0.2.1