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Tools / Formatters & Beautifiers

JSON Formatter & Beautifier

Inspect strict JSON and write a readable, indented document.

Input

0 UTF-16 code units

Optional local draft

Saving stores a plaintext draft in this browser on this device. Do not save secrets or use this on a shared device. Nothing is saved or loaded automatically. Reset does not delete a saved draft; use Delete local draft.

No draft has been loaded.

Import a local text file

Output

Work through the task
Make a JSON value easier to read without changing its decoded types or array order.
  1. Choose indentation, paste a JSON document and format it.
  2. Layout and numeric spelling may normalize; this does not repair invalid syntax.
  3. Review the result before copying or downloading. Editing an input invalidates the previous result; keep an original if the transformation matters.
Example to check
{"ready":true,"items":[2,1]} retains a boolean ready value and the array order 2, then 1.
Limits and output behavior
Up to 100,000 input characters, 10,000 values and 40 data levels. Strict JSON rejects duplicate keys, trailing commas, nonfinite numbers and unsafe integers; quote large identifiers to retain their digits.
Troubleshooting
Read the syntax location, then check for trailing commas, duplicate keys, unsafe integers and the size/depth guards. Correct the source and run again; formatting does not repair it automatically.
Questions
Will formatting preserve the original whitespace and number spelling?
No. Decoded values and array order are retained, while layout whitespace and numeric spelling can normalize. Keep the original source when its lexical form matters.
Input and privacy
Processing runs in this browser. Inputs are not saved automatically. An explicitly chosen local draft, where offered, is plaintext storage on this device. Downloaded files, clipboard contents and browser extensions have separate retention behavior.