What does the YAML formatter do?

The formatter normalises indentation to consistent 2-space increments and ensures there is a space after every colon separator. It produces a clean, readable YAML file without changing the data values.

Does this tool validate YAML?

The tool parses the YAML to build the tree view, which effectively validates the structure. If the YAML cannot be parsed, an error message is shown in the tree panel. The formatter itself performs a best-effort normalisation even on partially invalid input.

Is my YAML uploaded anywhere?

No. All formatting and parsing happens entirely in your browser. No data is sent to a server.

Can I use this for Kubernetes or Docker Compose YAML?

Yes. Kubernetes manifests and Docker Compose files are standard YAML. Paste them directly into the input panel to format them and inspect their structure in the tree view.

What types are colour-coded in the tree view?

Strings appear in green with quotes, numbers in blue, booleans in orange, and null values in grey. Arrays show their item count in brackets and objects show their key count in braces.

Does the tree view support deep nesting?

Yes. The tree view renders to any depth. Nodes at depth 0 and 1 are expanded by default; deeper nodes start collapsed so the view is not overwhelming for large documents.

What is the difference between YAML and JSON?

YAML is a superset of JSON designed to be more human-readable. It uses indentation instead of braces, supports comments, and has more expressive syntax for scalars. JSON is more portable and is the default format for APIs.

Can this formatter handle multi-document YAML files (with --- separators)?

The current parser handles single-document YAML. Multi-document files separated by --- are not fully supported. Split the documents and process each one individually.

YAML Formatter & Viewer

Format YAML with normalized indentation and explore its structure as an interactive tree.

Input YAML

Formatted YAML will appear here

Free online YAML formatter and tree viewer

YAML is the configuration language of modern infrastructure: Kubernetes, Docker Compose, GitHub Actions, Ansible, and dozens of other tools all use YAML. But YAML's whitespace-sensitive syntax makes it easy to introduce indentation errors that are invisible to the eye. This tool normalises indentation and lets you visually explore the structure of any YAML document in an interactive tree.

The tree view is especially useful for large, deeply nested configurations like Kubernetes manifests. You can collapse entire branches to focus on the part you care about, and the colour-coded value types make it easy to spot type mismatches at a glance. All processing is client-side: paste your YAML, explore it, copy the formatted output, and move on.

Step-by-step guide

1
Paste your YAML
Copy any YAML content: configuration files, CI/CD pipelines, Kubernetes manifests, Docker Compose files: and paste it into the input panel.
2
Use Sample to try it out
Click Sample to load example YAML and see both the formatted output and tree view immediately.
3
Switch between Formatted and Tree View
Use the tabs on the output panel to toggle between the normalised formatted YAML and the interactive collapsible tree.
4
Expand and collapse the tree
In Tree View, click any key with children to expand or collapse that branch. Types and values are colour-coded for quick reading.
5
Copy the formatted YAML
On the Formatted tab, click Copy to grab the normalised YAML ready to paste back into your project.

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Frequently Asked Questions

What does the YAML formatter do?: The formatter normalises indentation to consistent 2-space increments and ensures there is a space after every colon separator. It produces a clean, readable YAML file without changing the data values.
Does this tool validate YAML?: The tool parses the YAML to build the tree view, which effectively validates the structure. If the YAML cannot be parsed, an error message is shown in the tree panel. The formatter itself performs a best-effort normalisation even on partially invalid input.
Is my YAML uploaded anywhere?: No. All formatting and parsing happens entirely in your browser. No data is sent to a server.
Can I use this for Kubernetes or Docker Compose YAML?: Yes. Kubernetes manifests and Docker Compose files are standard YAML. Paste them directly into the input panel to format them and inspect their structure in the tree view.
What types are colour-coded in the tree view?: Strings appear in green with quotes, numbers in blue, booleans in orange, and null values in grey. Arrays show their item count in brackets and objects show their key count in braces.
Does the tree view support deep nesting?: Yes. The tree view renders to any depth. Nodes at depth 0 and 1 are expanded by default; deeper nodes start collapsed so the view is not overwhelming for large documents.
What is the difference between YAML and JSON?: YAML is a superset of JSON designed to be more human-readable. It uses indentation instead of braces, supports comments, and has more expressive syntax for scalars. JSON is more portable and is the default format for APIs.
Can this formatter handle multi-document YAML files (with --- separators)?: The current parser handles single-document YAML. Multi-document files separated by --- are not fully supported. Split the documents and process each one individually.

AlteredIdea vs alternatives

vs server-side tools: Everything runs in your browser: your data never leaves your device.

vs VS Code extensions: No install needed. Works instantly in any browser.

vs paid tools: Completely free, no account required.

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