About Indentio

A focused tool for developers who work with XML and JSON every day and are tired of hunting for the one character that broke everything.

Why Indentio exists

Every developer has lived this moment: an API call fails, a config file won’t load, a build breaks — and the only clue is “invalid JSON” or “XML parse error”. You paste the file into the first online formatter you find, and it tells you… the same thing, with no location, on a page buried in pop-ups.

Indentio was built out of that frustration. The idea is simple: a validator should behave like a good compiler. It should point at the exact line and column where parsing failed, explain the problem in plain English, and — when the fix is unambiguous — offer to make it for you. That’s the whole product: one fast page that finds the stray comma or the unclosed tag in seconds instead of minutes.

What it does

• Formats and minifies JSON and XML with your preferred indentation, preserving comments and CDATA in XML.
• Validates as you type, underlining each error in red at its precise line and column with a plain-English explanation.
• Auto-fixes common JSON mistakes — trailing commas, single quotes, unquoted keys, missing brackets — in one click.
• Converts between JSON and XML, handling attributes and arrays sensibly in both directions.
• Shows a collapsible tree view so you can explore a document’s structure instead of scrolling raw text.

If you’re learning the formats themselves, our guides explain the most common JSON and XML errors, the syntax rules behind them, and how to avoid them next time.

How it works

The whole app runs client-side in your browser. It’s built with Astro for a fast, lightweight static site and CodeMirror for the editor, with battle-tested parsing and repair libraries doing the heavy lifting. Because nothing is sent to a server, it’s both fast and private — there is literally no backend that could store your documents.

Who’s behind it

Indentio is designed, built, and maintained by Svetoslav Barakov, an independent software developer from Bulgaria. It’s a small, personal project with a simple goal: make the best free XML/JSON tool on the web, without accounts, paywalls, or data collection. Feedback and bug reports are genuinely welcome — get in touch.

Your privacy

We never receive the documents you paste — they are processed entirely on your device and are never uploaded, logged, or stored. The site is supported by unobtrusive ads instead of selling data or features. See our privacy policy for details.

Roadmap

• Schema validation (XSD / JSON Schema)
• JSONPath and XPath querying
• Diffing two documents side by side
• Shareable, self-contained permalinks (still without server storage)

Ready to try it? Format some JSON or format some XML.