JSON Formatter & Validator
Enterprise safeFormat, validate and minify JSON with error line highlighting.
Frequently asked questions
Is my JSON uploaded anywhere?
No. Formatting, validation, and minification all run in your browser tab via JavaScript — the text never leaves your device or touches a server.
Why does it say my JSON is invalid?
The error message includes the line and column of the first problem — usually a trailing comma, an unquoted key, or a missing bracket. Fix that spot and the rest is checked incrementally as you type.
What's the difference between Format and Minify?
Format pretty-prints with your chosen indent (2, 4 spaces, or a tab) for readability. Minify strips all non-essential whitespace to produce the smallest valid JSON, useful before sending a payload over the wire.
Is there a file-size limit?
No hard limit, but very large documents (multiple megabytes) run through a Web Worker automatically so the tab doesn't freeze while formatting.
About this tool
Use this formatter when a JSON document needs a readable structure, a quick syntax check, or a compact form for transport and storage.
Workflow
- Paste or type the document into the editor.
- Choose Format for readable indentation or Minify for the smallest valid output.
- Use the highlighted line and column when validation identifies a syntax error.
- Copy the result only after checking the structure and values.
Things to know
- JSON requires double-quoted property names and does not allow trailing commas.
- Large documents are moved to a worker automatically to keep the page responsive.
- Formatting changes whitespace; it does not change the underlying values.
JSON Formatter & Validator on devsutils.com — Format, validate and minify JSON with error line highlighting. It runs entirely in your browser: the input you paste is processed by client-side JavaScript and is never uploaded, logged, or stored. devsutils.com is a privacy-first suite of 70 developer utilities — JSON formatter, JWT decoder, Base64 encoder, regex tester, UUID generator, hash generator and more — with no accounts and no server-side processing.