YAML Formatter & Validator

Free

Free online YAML formatter. Beautify YAML with configurable indent, validate syntax with line-level error reporting, and convert between YAML and JSON. Built for GitHub Actions, Kubernetes, and pytest configs.

#yaml#formatter#validator#github-actions#kubernetes

YAML Workspace

Format, Validate & Convert

Valid YAML

YAML Input

Formatted YAML

name: CI Pipeline
'on':
  push:
    branches:
      - main
  pull_request:
    branches:
      - main
jobs:
  test:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        node-version:
          - 18
          - 20
          - 22
    steps:
      - uses: actions/checkout@v4
      - name: Setup Node.js
        uses: actions/setup-node@v4
        with:
          node-version: ${{ matrix.node-version }}
      - run: npm ci
      - run: npm test

Frequently Asked Questions(click to expand)

What is YAML?

YAML (YAML Ain't Markup Language) is a human-readable data serialization format. It's widely used for configuration files in CI/CD pipelines (GitHub Actions, GitLab CI), container orchestration (Kubernetes, Docker Compose), and Python testing frameworks (pytest, tox).

How do I convert YAML to JSON?

Select the "YAML → JSON" mode above, paste your YAML content in the left pane, and the equivalent JSON will be generated instantly in the right pane. You can copy it with one click.

What YAML syntax errors can this tool detect?

This validator detects indentation errors, duplicate keys, invalid characters, missing colons, incorrect nesting, and malformed arrays/objects. Error messages include the exact line number for quick debugging.