YAML Formatter
Format, validate, and pretty print YAML files instantly in your browser.
YAML Formatter Features
Format and validate YAML with ease.
Catches syntax errors with helpful messages.
Formats YAML with consistent indentation.
Choose 2 or 4 space indentation.
Key Takeaways
- Your YAML is parsed locally in your browser and stays on your device, with no upload to a server.
- Format parses and re-emits clean YAML at your chosen 2 or 4 space indent, while Validate only checks syntax and updates the status line without changing anything.
- Formatting strips comments because the document is parsed into a data structure and rebuilt, so if you need to keep inline comments, use Validate and edit by hand instead.
- YAML forbids tab characters for indentation, so replace any leading tabs with spaces, and use a dedicated YAML to JSON converter if you need to change formats.
How to Format YAML
Paste your YAML
Drop your YAML into the input editor. This can be a Kubernetes manifest, a Docker Compose file, a CI pipeline config, or any other YAML document. The text stays on your device and is parsed locally in your browser.
Pick indent size and click Format
Choose 2 or 4 space indentation, then click Format YAML. The tool parses your input, rebuilds it from the resulting data structure, and re-emits it with consistent spacing and long lines kept intact rather than wrapped.
Validate, then copy
Use Validate to check syntax without changing anything, and watch the status line for a confirmation or a specific error. When the output looks right, click Copy Result to put the formatted YAML on your clipboard, or Clear to start over.
Format vs Validate: What Each Button Does
This formatter runs two related but distinct actions on your YAML. Knowing which one to use saves time when you only want to check syntax versus when you want clean, normalized output.
| Aspect | Format YAML | Validate |
|---|---|---|
| Main purpose | Parse and re-emit clean, indented YAML | Confirm the document parses without errors |
| Changes the output box | Yes, writes formatted YAML | No, only updates the status line |
| Indent setting used | Yes, 2 or 4 spaces | Not applicable |
| Error reporting | Shows the parser message and clears output | Shows the parser message inline |
| Comments | Stripped during re-emit | Preserved, since nothing is rewritten |
| Best for | Normalizing messy or inconsistent files | Quick syntax checks before committing |
When This Formatter Fits
Cleaning up config files
Hand-edited Kubernetes, Docker Compose, or CI files often drift into mixed indentation. Reformatting with a fixed 2 or 4 space indent gives every file the same predictable shape.
Catching syntax errors early
Bad indentation, stray tabs, or unclosed quotes break YAML in ways that are hard to spot by eye. Validate surfaces the parser message so you can fix it before a deploy fails.
Normalizing before review
When YAML comes from many contributors, formatting it the same way reduces noisy diffs and makes pull requests easier to read and compare.
When to look elsewhere
If you must keep inline comments, format manually instead, since parsing strips them. To turn YAML into JSON, use a dedicated YAML to JSON converter rather than this formatter.
Common Problems and Fixes
My comments disappeared after formatting
This is expected. Formatting parses your YAML into a data structure and re-emits it, and the parser does not retain comments. If comments matter, run Validate to check syntax and keep editing the original by hand.
I get a parse error mentioning a tab
YAML does not allow tab characters for indentation. Replace any leading tabs with spaces, then format again. The error message in the status line points to where the parser stopped.
The output looks different from my input layout
The formatter rebuilds YAML in a normalized style, so flow versus block layout, quoting, and key order may change while the underlying data stays the same. Long lines are kept on one line rather than wrapped.
Nothing happens or the library will not load
If the status line reports that the library is not loaded, refresh the page so the formatting script can load fully. An empty input simply clears the output, so make sure you pasted content before clicking Format.
About YAML Formatter
Format and validate YAML configuration files with configurable indent size. Highlights syntax errors instantly.
Frequently Asked Questions
Is this tool free to use?
Yes, this tool is completely free.
No account or registration is required.
You can use it as many times as you like.
Is my data private?
Browser-side workflows run locally.
Your data is never sent to any server.
We do not store, log, or share your input.
Does it work on mobile?
Yes, the tool is fully responsive.
It works on phones, tablets, and desktops.
No app download is needed.
Do I need to install anything?
No installation is required.
It runs entirely in your web browser.
Works on any modern browser without plugins.
Is there a file size limit?
There is no strict file size limit.
Very large inputs may be limited by browser memory.
For best performance, keep inputs under a few MB.
Can I use the output commercially?
Yes, there are no restrictions on usage.
The output belongs entirely to you.
Use it for personal or commercial projects freely.
What browsers are supported?
All modern browsers are supported.
This includes Chrome, Firefox, Safari, and Edge.
Keep your browser updated for best results.
How accurate is the result?
Results are highly accurate for standard inputs.
Edge cases may produce unexpected output.
Always review the output before using it in production.
Sources and References
Format and tool details on this page are based on the official specifications and documentation below.
- YAML 1.2 Specification- yaml.org