YAML Formatter & Validator | Online YAML Beautifier & Checker
Beautify, format, and validate YAML with automatic indentation and syntax highlighting. Detect tabs, inconsistent spacing, and duplicate keys — all securely in your browser.
How to Use This Tool
- 1
Paste or type YAML into the input area.
- 2
Use Live mode for instant validation or Manual mode and click ‘Format’.
- 3
Fix issues using line numbers for guidance (e.g., spacing, quotes, or keys).
- 4
Adjust indentation (2/4 spaces) and copy or download the formatted YAML.
Use Cases & Examples
Kubernetes YAML Validation
Format and validate Kubernetes manifests before deployment to ensure indentation accuracy.
Docker Compose File Formatting
Fix spacing and validate docker-compose.yml to maintain structure integrity.
CI/CD Configuration Review
Lint and validate YAML CI/CD pipeline files (GitHub Actions, GitLab CI, CircleCI).
Ansible Playbook Formatting
Reformat and validate Ansible playbooks, roles, and variable files for readability and consistency.
How YAML Formatting and Validation Works
YAML uses indentation (spaces only) to define hierarchy — tabs are invalid.
The validator parses YAML 1.2 syntax and reports exact line/column for errors.
Anchors, aliases, comments, and multi-line strings are preserved during formatting.
Duplicate keys and control characters are flagged for correction.
Frequently Asked Questions
Q.Can I use tabs for indentation in YAML?
A. No — YAML forbids tabs by specification. Use spaces for indentation (2 or 4) to avoid parse errors.
Q.Does this formatter preserve anchors and aliases?
A. Yes. Anchors (&) and aliases (*) are preserved when reformatting YAML content.
Q.Why does my YAML fail validation?
A. Typical YAML errors include tabs, inconsistent spacing, missing colons or quotes, and duplicate keys. The validator points to the exact line for correction.
Q.Can I use this for Kubernetes or Docker Compose files?
A. Yes. The formatter supports Kubernetes, Docker Compose, Ansible, and CI/CD YAML configs following YAML 1.2 standards.
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