YAML Formatter, Validator & YAML↔JSON Converter

Format and validate YAML. Convert between YAML and JSON instantly. Detect errors with line numbers. 100% client-side.

Free Always No Account Needed 100% Client-Side

About this tool

YAML (YAML Ain't Markup Language) is a human-friendly data serialization format widely used for configuration files: Kubernetes manifests, Docker Compose, GitHub Actions, Ansible playbooks, and many more.

YAML's indentation-based syntax is clean to write but tricky to debug when something goes wrong — a misaligned space can break an entire config file.

This tool provides:

YAML Formatting — normalize indentation and formatting to a consistent style.

YAML Validation — parse YAML and catch all syntax errors with precise line numbers and descriptive messages.

YAML → JSON — convert YAML configs to JSON for use in JavaScript applications or APIs that require JSON.

JSON → YAML — convert JSON API responses or configs to clean, readable YAML.

Supports YAML 1.2 spec including anchors (&), aliases (*), multi-line strings (| and >), and complex types.

Frequently Asked Questions

What's the difference between YAML and JSON?
YAML is a superset of JSON and is more human-readable, supporting comments, multi-line strings, and anchors. JSON is stricter and better for machine-to-machine exchange.
Does YAML support comments?
Yes! Use # for comments. JSON does not support comments at all.
What are YAML anchors and aliases?
Anchors (&name) define a reusable block; aliases (*name) reference it. This avoids repeating configuration blocks.
Why is indentation so important in YAML?
YAML uses indentation (spaces only, not tabs) to define structure. Incorrect indentation changes the meaning of the document.

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