About YAML Validator
Validate your YAML documents instantly with our free online YAML validator. Check syntax, detect errors with line numbers, and ensure your YAML is well-formed. Perfect for developers working with Docker Compose, Kubernetes manifests, GitHub Actions, Ansible playbooks, and CI/CD configurations. All processing happens client-side — your data never leaves your device.
Features
- Pure Client-Side: No data sent to any server. Your YAML stays private.
- File Upload & Drag-Drop: Upload .yaml, .yml, or .txt files directly.
- Detailed Error Messages: Clear error messages with exact line numbers when validation fails.
- Document Statistics: See key count, arrays, objects, and document size at a glance.
- One-Click Actions: Copy validation report to clipboard or download as a text file.
- YAML 1.2 Support: Handles anchors, aliases, and all standard YAML types.
How to Use
- Paste your YAML into the input area, or drag & drop a file.
- Click Validate YAML.
- Review the validation result — green for valid, red for errors.
- Copy or download the validation report if needed.
Common Use Cases
- CI/CD Configs: Validate GitHub Actions, GitLab CI, or Docker Compose YAML before deployment.
- Kubernetes: Check K8s manifest YAML for syntax errors before applying.
- Ansible: Ensure playbook YAML is well-formed before running.
- API Specs: Validate OpenAPI/Swagger YAML definitions.
FAQ
Is this tool free?
Yes, 100% free. No sign-up, no limits.
Is my data private?
Absolutely. All validation happens in your browser. We never see your data.
What YAML versions are supported?
We support YAML 1.2 via the js-yaml library, handling anchors, aliases, and all standard types.
How are errors reported?
Errors include the exact line number and a descriptive message so you can quickly locate and fix issues.
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