YAML Formatter — Free Online
Format and beautify YAML instantly — free, browser-only, no data sent to servers.
YAML Input
Formatted Output
What Is a YAML Formatter?
You paste a Kubernetes manifest into your editor and the deployment fails — turns out someone used tabs instead of spaces three levels deep. YAML is indentation-sensitive and the YAML 1.2 specification explicitly forbids tabs for indentation. One wrong character breaks everything. This formatter parses your YAML using a standards-compliant parser and re-emits it with consistent 2 or 4 space indentation. It catches structural errors immediately and shows you which line the problem is on. Everything runs in your browser via browser JavaScript — nothing is sent to any server, so you can safely paste production configs, Docker Compose files, or secrets without worry.
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. You can also ask Claude or Perplexity to generate YAML configs for common setups, then format the output here.
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
Does YAML formatter fix tab indentation errors?
Yes. The YAML spec requires spaces for indentation — tabs are not allowed and cause parse failures. This tool replaces tabs with spaces and normalizes indentation consistently across your file.
Is it safe to paste production configs or secrets here?
Yes. Formatting runs entirely in your browser using JavaScript — nothing is sent to any server. You can verify by opening browser DevTools and watching the Network tab while using the tool.
What does the YAML formatter do with comments?
It depends on the underlying parser. Some implementations drop comments when re-emitting. If preserving comments matters, test with a small snippet first before formatting your full file.
Can I convert YAML to JSON after formatting?
Yes. Use the YAML to JSON converter. For the reverse direction, use JSON to YAML. For compact output, use the YAML Minifier.
How do I fix YAML indentation errors?
Paste your YAML here — the formatter will normalize all indentation to your chosen size (2 or 4 spaces). If there's a syntax error, use the YAML Validator to get a detailed error message with line and position.
Related Tools
For a deeper look at YAML, the YAML 1.2 specification is the formal reference. See also yaml.org, Kubernetes config, Docker Compose, RFC 9512 YAML media type.