📄 YAML Validator
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Validate and convert YAML to JSON. Detect syntax errors with line numbers.
Validate YAML syntax and instantly see the equivalent JSON output. Built on js-yaml 4.3, this tool supports YAML 1.2 including anchors, aliases, multi-line strings, and complex nested structures. Error messages include line numbers so you can fix indentation issues, missing colons, or duplicate keys fast. All parsing runs in your browser — YAML configs (often containing secrets) never leave your machine.
📋 When to Use the YAML Validator
Your CI pipeline just failed with "invalid YAML" and all you have is the stack trace — paste the config here, find the indentation error on line 47, and fix it before the next push. Validation runs locally — YAML configs (which often contain secrets) never leave your machine.
⚙️ How the YAML Validator Works
The YAML Validator processes your input using conversion algorithms that run entirely in your browser. When you paste or upload content and select the output format, JavaScript parses the input, transforms it using format-specific logic (encoding, decoding, parsing, serializing), and produces the converted output. For file conversions, all processing uses browser-native APIs and JavaScript libraries loaded from CDN — your files are never uploaded to any server. The entire pipeline from input to output stays on your device.
How to Use the YAML Validator
- Paste your YAML — Drop any YAML content into the input area. Sample YAML is pre-loaded.
- Click Validate & Convert — Checks for syntax errors and displays the equivalent JSON. Any indentation or formatting issues are reported with line numbers.
- Or click To JSON — Skip validation feedback and go straight to the JSON output. Useful when you're confident the YAML is valid.
- Fix errors and retry — If validation fails, the error message tells you exactly what's wrong. Fix your YAML and validate again.
Frequently Asked Questions
What YAML features are supported?
The js-yaml library supports YAML 1.2 including anchors, aliases, multi-line strings, and complex nested structures. Most common YAML features work out of the box.
Why is my YAML invalid?
Common issues: inconsistent indentation (tabs vs spaces), missing colons after keys, unquoted strings that look like numbers/booleans, or duplicate keys. The error message usually points to the exact line.
Can I use this for Kubernetes/Docker Compose files?
Yes! The validator works with any YAML, including Kubernetes manifests, Docker Compose files, Ansible playbooks, and CI/CD configs. It validates structure, not schema.
What's the difference between Validate and To JSON?
Validate shows a "Valid YAML" message plus the JSON. To JSON skips the validation message. Both run the same parser — the difference is just the display.
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