YAML Validator

Validate YAML syntax and find errors instantly in your browser

Paste YAML on the left to validate...

What is YAML Validator?

The YAML Validator checks your YAML syntax for errors and reports them with exact line numbers, making it easy to find and fix problems in configuration files. YAML is used in Docker Compose, Kubernetes, GitHub Actions, Ansible, and many other tools — a single indentation mistake or tab character can break an entire deployment. This tool catches common YAML errors instantly in your browser without any server upload.

Why Use DevBench YAML Validator?

DevBench tools are built with one principle: everything runs in your browser. Unlike most online tools that upload your data to remote servers, DevBench processes everything locally using client-side JavaScript. This means your files, code, and sensitive data never leave your device. There are no accounts to create, no usage limits, no watermarks, and no paywalls. Every tool on DevBench is completely free to use as many times as you need. Whether you are a professional developer, a student learning to code, or someone who occasionally needs a quick utility, DevBench gives you instant access to powerful tools without friction.

How to Use YAML Validator

Using the YAML Validator is straightforward and requires no installation or sign-up. Follow these steps to get started:

  1. Paste your YAML content into the input textarea
  2. Errors appear instantly with line numbers
  3. Click Load Sample to see correct YAML syntax
  4. Fix the errors shown and re-paste to confirm the YAML is clean
  5. Use for validating config files before deployment

All processing happens directly in your browser, so your data stays private and results are instant.

Examples

Here are some common examples of how the YAML Validator is used in real-world scenarios:

  • Validate a Docker Compose YAML file before running docker-compose up
  • Check a Kubernetes manifest for syntax errors before kubectl apply
  • Validate a GitHub Actions workflow YAML before pushing
  • Check an Ansible playbook YAML for indentation errors
  • Validate a config.yaml file for a web application

Use Cases

The YAML Validator is used by developers, designers, and professionals across many industries. Common use cases include:

  • DevOps engineers validating Kubernetes and Docker YAML files
  • Developers checking GitHub Actions workflow syntax
  • Ansible users validating playbook YAML before running
  • Anyone debugging YAML indentation and syntax errors
  • CI/CD pipeline developers catching YAML errors early
  • Students learning YAML syntax rules
  • Teams reviewing configuration files before deployment

Whether you are a beginner learning the basics or an experienced developer working on complex projects, this tool is designed to fit seamlessly into your workflow.

Frequently Asked Questions

Here are answers to the most common questions about the YAML Validator:

What are the most common YAML errors?

The most common YAML errors are: using tab characters instead of spaces for indentation, inconsistent indentation levels, missing spaces after colons, and unmatched quotes.

Why does YAML not allow tabs?

The YAML specification explicitly forbids tab characters for indentation because different editors display tabs at different widths. Always use spaces — 2 spaces per level is the most common convention.

Is my YAML sent to a server?

No. All validation runs entirely in your browser using JavaScript. Your YAML content never leaves your device.

Does this validate YAML schemas?

This tool validates YAML syntax only. It does not validate against a specific schema like Kubernetes CRD schemas. For schema validation, use a dedicated schema validator.

What indentation should I use in YAML?

Use 2 spaces per indentation level. This is the most widely accepted YAML convention used by Kubernetes, Docker Compose, and GitHub Actions.