YAML Formatter
Format, minify, and validate YAML with syntax highlighting
YAML Input
Formatted Output
What Is a YAML Formatter?
YAML (YAML Ain't Markup Language) is widely used for config files in Kubernetes, Docker Compose, GitHub Actions, and many other tools. Unlike JSON, YAML uses indentation for structure—no brackets required. That makes it readable, but also fragile: wrong spaces, tabs instead of spaces, or inconsistent nesting cause parse errors. The YAML 1.2 specification defines the rules.
A YAML formatter normalizes indentation and line breaks so your document is valid and consistent. This tool parses your YAML and reformats it with 2 or 4 spaces. It runs entirely in your browser. Nothing is sent to a server, so it's safe to use with production configs, secrets, or sensitive data.
YAML Formatting Examples
Format YAML for consistent indentation. Telecom-themed examples:
Example 1: Subscriber record
Formatted output:
Example 2: Subscribers list
Formatted output:
Click the Sample button above to load more examples into the editor.
How to Use This Tool
Paste or Upload
Copy your YAML and paste it into the left editor. You can also click Upload to load a .yaml or .yml file. The Sample button loads example data. Invalid YAML will show an error—use the YAML Validator to diagnose.
Adjust and View Output
The right panel updates automatically. Use the indent buttons (2 or 4 spaces) to choose your preferred style. Sort Keys alphabetizes keys for consistent output. The YAML spec requires spaces (not tabs) for indentation.
Copy or Download
Use Copy to put the result on your clipboard, or Download to save it as a file. For converting to JSON, use YAML to JSON. For the reverse, use JSON to YAML. For compact output, use the YAML Minifier.
When YAML Formatting Helps
Most developers need a formatter when working with Kubernetes manifests, Docker Compose files, or CI/CD configs like GitHub Actions. Manually edited YAML often has indentation errors—a single extra space or tab can break deployment. Formatting it here gives you valid, consistent output you can paste back into your project.
Config files like application.yml (Spring Boot) or .gitlab-ci.yml often have deep nesting. Inconsistent indentation makes them hard to read and review in pull requests. Running them through here normalizes the structure. For converting to JSON or XML, use YAML to JSON or YAML to XML.
It's also useful before sharing YAML with teammates. Formatted config in a Slack message or ticket is much easier to read. Running it through the YAML Validator first can catch syntax issues before anyone else sees them.
Frequently Asked Questions
Is my data private?
Yes. The formatting happens in your browser using JavaScript. No data is sent to any server. You can confirm this by opening your browser's Network tab while using the tool.
Why does YAML use spaces instead of tabs?
The YAML spec requires spaces for indentation. Tabs are not allowed. Mixing tabs and spaces causes parse errors. Use 2 or 4 spaces consistently throughout your file.
Can I convert YAML to JSON?
Yes. Use the YAML to JSON tool.
What if my YAML has invalid indentation?
The tool will show a parse error with line and position. Use the YAML Validator to get detailed error messages. Common fixes: replace tabs with spaces, ensure consistent indent size, and check for misaligned nested blocks.
Does this preserve comments?
It depends on the parser. Some implementations drop comments when parsing and re-emitting. Check the output.
Related Tools
For a deeper look at YAML, the YAML 1.2 specification is the formal reference. Learn X in Y minutes offers a quick reference. For JSON comparison, see MDN.