Online YAML Validator & Linter

Validate complex YAML configurations for Kubernetes, Docker, and Ansible. Detect indentation errors and syntax issues instantly.

EN TR RU

Input

YAML
Uses yaml_parse() if available, otherwise a small YAML subset parser.

Output

Mastering Infrastructure as Code: The Importance of Valid YAML

In the realm of DevOps and Cloud Native development, YAML is the unspoken king of configuration. From defining CI/CD pipelines in GitHub Actions to orchestrating containers in Docker Compose and Kubernetes, almost everything relies on `.yaml` files. However, YAML is deceptively simple; its strict reliance on whitespace indentation means a single misplaced space can crash an entire deployment. Our Online YAML Validator acts as a pre-flight check for your infrastructure code. It parses the structure, highlights indentation inconsistencies, and ensures your scalars and sequences are formatted correctly before you commit them to your repository.

Debugging "Silent" Parsing Errors

One of the most frustrating aspects of YAML involves "silent" type coercion errors. For instance, creating a country code list with keys like `NO` (Norway) might be interpreted as a boolean `false` in YAML 1.1 spec. Similarly, unquoted version numbers like `3.10` might be truncated to `3.1`. Our Linter helps visualising how parsers interpret your data. By converting your YAML to a strictly typed JSON preview alongside the validation, you can verify that your strings, booleans, and floats are being parsed exactly as you intended, preventing catastrophic runtime configuration failures.

Handling Anchors, Aliases, and Multi-line Blocks

Advanced YAML features like Anchors (`&`) and Aliases (`*`) are powerful for adhering to the DRY (Don't Repeat Yourself) principle but are prone to syntax errors during manual editing. Our tool correctly validates reference integrity, ensuring that every alias points to a valid anchor. Furthermore, it assists in formatting complex multi-line strings—whether you are using the pipe (`|`) for literal blocks or the fold (`>`) operator—making sure line breaks and trailing spaces are preserved or stripped according to the specification.

FAQ
YAML strictly forbids tab characters for indentation; you must use spaces. Our tool detects mixed tabs/spaces or misaligned nesting levels and flags the exact line causing the structural break.
Yes. Ansible relies heavily on YAML lists and dictionaries. Our validator effectively checks the syntax of tasks, handlers, and variable definitions within your playbooks.
Yes. We use a client-side parsing engine. Your database credentials, secret keys, or infrastructure details processed in this tool remain in your browser's memory and are never transmitted to us.
Yes, standard YAML allows multiple documents separated by `---`. Our validator recognizes this delimiter and processes each document segment individually for errors.
Block style uses indentation (typical YAML), while Flow style uses explicit braces `[]` and `{}` (like JSON). Our tool supports and validates both styles, even when mixed in the same file.