ConfigGenerator

YAML Validator

Validate YAML syntax online, find indentation errors, check Kubernetes, OpenAPI, Docker Compose, GitHub Actions, Helm, and schema-based YAML.

Output:A ready-to-use configuration file for YAML Validator with best practices applied.

What is this tool?

Quick Answer: What is a YAML Validator?

Use a YAML Validator when you need to check YAML syntax, verify indentation, find duplicate keys, test schema compatibility, and catch configuration errors before deployment. It is an essential tool for parsing YAML files like Kubernetes manifests, Docker Compose, and CI/CD pipelines to ensure they are structurally valid.

YAML Validator vs YAML Linter

A YAML Validator checks if your file is structurally correct according to the YAML 1.1 or 1.2 specification (e.g., checking for unclosed strings, tab characters, or broken mapping). A YAML Linter (like `yamllint`) goes a step further and enforces stylistic rules, such as maximum line length, trailing spaces, or specific quote usage. This online tool acts as a syntax validator.

Common YAML Syntax Errors

If your YAML is invalid, it is likely due to one of these common mistakes:

  • Using Tabs: YAML absolutely forbids the use of tabs for indentation. You must use spaces.
  • Bad Indentation: Children elements must be indented consistently further than their parent.
  • Unescaped Colons in Strings: A colon followed by a space (: ) is an indicator of a key/value pair. If you have this inside a string, you must wrap the string in quotes.
  • Duplicate Keys: Having the same key twice in the same dictionary is invalid in YAML 1.2 and will cause errors in most parsers.

Validate YAML with JSON Schema

Because YAML is a superset of JSON, many developers use JSON Schema to validate YAML configuration files. This validator supports checking your YAML structure against popular schemas, ensuring that your Docker Compose, Kubernetes, GitHub Actions, Helm, CloudFormation, Azure Pipelines, and Ansible files not only have valid syntax, but also have the correct keys and data types required by those platforms.

How to Use This Tool

  1. Paste Code: Paste your YAML configuration into the editor or upload your .yml file.
  2. Check Syntax: The validator parses the file instantly. If valid, you'll see a success message.
  3. Fix Errors: If invalid, the validator will show the exact line number, column, and a plain-English explanation of the error so you can fix it.

Frequently Asked Questions

What is a YAML Validator?
A YAML Validator is a tool that parses YAML code to ensure it follows the official YAML syntax rules. It catches errors like bad indentation, tab characters, and unescaped colons.
How do I validate YAML online?
Simply paste your YAML text into this validator. It will automatically parse the structure and tell you if it is valid or point out the exact line where an error occurred.
What is a YAML syntax error?
A syntax error means your code violates the rules of the YAML language. The most common errors are using tabs instead of spaces, misaligning indentation levels, or forgetting to quote strings that contain special characters like colons.
How do I fix YAML indentation?
Ensure that you are using spaces (not tabs). Check that child elements are indented exactly 2 spaces (or your chosen standard) relative to their parent element. Tools like our YAML Formatter can help fix this automatically.
Can I validate Kubernetes YAML?
Yes, this validator ensures your Kubernetes YAML is syntactically valid. If you select the Kubernetes schema, it will also verify that you have required fields like apiVersion, kind, and metadata.
Can I validate OpenAPI YAML?
Yes, you can validate OpenAPI (Swagger) YAML files. Because these files can get very large, validation is processed efficiently in your browser without uploading.
Can I validate YAML with JSON Schema?
Yes. Many configuration files (like Docker Compose or GitHub Actions) have official JSON Schemas. This tool can apply those schemas to your YAML to ensure the keys and data types are correct.
Is YAML validation done locally?
Yes. All YAML parsing and validation is executed by JavaScript in your local browser. Your configuration data is never sent to our servers.

How We Keep Your Configs Safe & Valid

Built-in Error Checking

Every file is checked against official rules. We catch missing fields and bad syntax. YAML indentation errors are flagged right away. Kubernetes, Terraform, and Docker specs are all covered. API versions and labels are verified too. You get valid output every time you generate.

100% Private & Local

All tools run in your browser only. Your API keys never leave your machine. We do not use any tracking scripts. No data is sent to any server. Passwords and secrets stay on your device. Crypto operations use the Web Crypto API. Your privacy is fully protected at all times.

Secure Settings by Default

Configs use safe defaults out of the box. Containers run as non-root users. Root filesystems are set to read-only. Dangerous Linux capabilities are dropped. Network policies limit pod-to-pod traffic. TLS 1.3 is enabled for web servers. Security headers are added where needed.

Ready for CI/CD & Git

Output files are ready for your Git repo. Use them with ArgoCD, Flux, or GitHub Actions. Files use clear formatting and comments. Code review is easy for your team. Indentation and key order are consistent. Test in staging before going to production. Every file is clean and well-structured.

Infrastructure as Code

Store configs in Git alongside your code. Terraform modules include typed variables. Backend configs support remote state locking. Outputs work across multiple modules. Ansible playbooks use clear task steps. Chef and Puppet configs are also supported. Every file works with version control tools.

Monitoring & Tracing

Set up Prometheus with auto-discovery rules. Create Grafana dashboards with template variables. Add alerting rules with severity labels. Use OpenTelemetry for trace collection. Forward logs to Loki or Elasticsearch. Connect to Jaeger or Tempo for tracing. Monitor metrics, logs, and traces together.

Container & Docker Safety

Dockerfiles use multi-stage builds for small images. Base images are pinned to exact versions. Dev files are excluded from final images. Health checks are added for orchestrator use. Containers switch to non-root users. Docker Compose uses named volumes and networks. Resource limits are set in deploy configs.

Multiple Output Formats

Export as YAML, JSON, HCL, or TOML. Kubernetes uses YAML with proper separators. Terraform uses HCL with correct escaping. JSON output has consistent indentation. Copy to clipboard with one click. Preview output with syntax highlighting. Line numbers help you review quickly.