YAML Formatter and JSON-YAML Converter Online

If you work with YAML config files — Kubernetes manifests, Docker Compose files, CI/CD pipelines — you know how one wrong indentation can ruin your whole day. This YAML formatter catches those mistakes before they cost you an hour of debugging.

What Does the YAML Formatter Do?

Paste in your YAML and the tool does three things. First, it validates your syntax and tells you exactly where the errors are. Second, it reformats your YAML with proper, consistent indentation. Third, it can convert between JSON and YAML in either direction.

That last one is honestly the feature I use most. I'll get a JSON API response and need to turn it into a YAML config block. Instead of doing it by hand (and inevitably messing up the indentation), I just paste, click convert, and copy the result.

Why YAML Formatting Matters

YAML is whitespace-sensitive. Unlike JSON where you have braces and brackets to define structure, YAML uses indentation. A single extra space or a tab where a space should be can break your entire configuration.

I've personally spent 45 minutes debugging a Kubernetes deployment that wouldn't apply, only to find that one line was indented with a tab instead of spaces. A YAML formatter would've caught that in two seconds.

JSON to YAML (and Back)

The converter handles both directions cleanly. Paste JSON, get YAML. Paste YAML, get JSON. It preserves your data types — numbers stay numbers, booleans stay booleans, nested objects stay nested.

This is especially handy when you're working with APIs that return JSON but your app expects YAML configuration. Or when you need to share a YAML config with someone who prefers reading JSON.

Common YAML Mistakes the Formatter Catches

Some things that trip people up constantly: using tabs instead of spaces, inconsistent indentation levels, missing colons after keys, and forgetting to quote strings that contain special characters like colons or hash marks.

The formatter highlights the exact line and position of each error, so you're not left guessing. It's like a linter, but you don't have to install anything.

Got a messy YAML file that needs cleaning up? Try it free →