YAML Basics

YAML (YAML Ain't Markup Language) is a human-readable data serialization format. GitHub Actions workflows are written entirely in YAML.

Key-Value Pairs

name: "My Workflow"
on: push

Lists/Arrays

Lists use a hyphen (-) followed by a space.

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
      - name: Run tests

Indentation is Critical!

YAML uses indentation (spaces, never tabs) to denote structure. Incorrect indentation will cause your pipeline to fail before it even runs.