About Codex
Codex formats, validates, and minifies JSON right in your browser. Paste in messy or minified JSON, format it into readable, indented text, or catch a syntax error before it breaks your code.
Features
- Format with 2-space, 4-space, or tab indentation
- One-click minify for compact output
- Validate with clear error location and message
- Sort object keys alphabetically
- Key count, nesting depth, and size at a glance
- Runs entirely in your browser, nothing is sent anywhere
How to use it
- Paste your JSON into the input box.
- Pick an indent style, then tap Format, Minify, or Validate.
- Fix any error shown in the status banner and try again.
- Tap Copy result to grab the finished output.
Frequently asked questions
What happens if my JSON has a syntax error?
Codex shows a red status message with the position of the problem, such as the line and column where parsing failed, so you can find and fix it quickly.
Does Minify remove comments?
Standard JSON does not support comments, so any content that isn't valid JSON — including comments — will cause validation to fail rather than being silently stripped.
What does Sort keys do?
It rewrites every object in the structure with its keys in alphabetical order, which can make diffs between two JSON files easier to read, without changing any values.
Is there a size limit?
Codex can handle very large JSON payloads, though extremely large files may feel slower since parsing and formatting both happen in your browser rather than on a server.
Is my data uploaded anywhere?
No. Parsing and formatting happen locally using your browser's built-in JSON engine, and nothing is sent to a server or stored once you leave the page.