Basic Syntax
# Key-value pairs
name: John Doe
age: 30
active: true
# Nested objects
address:
street: 123 Main St
city: Paris
country: France
# Inline object
address: { street: 123 Main St, city: Paris }
Lists
# Block list
fruits:
- apple
- banana
- cherry
# Inline list
fruits: [apple, banana, cherry]
# List of objects
users:
- name: Alice
role: admin
- name: Bob
role: user
Multiline Strings
# Literal block (preserves newlines)
description: |
Line one.
Line two.
Line three.
# Folded block (joins lines with spaces)
description: >
This is a long sentence
that spans multiple lines
but becomes one line.
# With chomp indicators
text: |+ # Keep trailing newlines
text: |- # Strip trailing newlines
Data Types
string: "hello"
number: 42
float: 3.14
boolean: true # or: false, yes, no, on, off
null_value: null # or: ~
date: 2026-02-22
timestamp: 2026-02-22T10:30:00Z
Anchors & Aliases
# Define anchor
defaults: &defaults
adapter: postgres
host: localhost
# Use alias
development:
<<: *defaults # Merge defaults
database: dev_db
production:
<<: *defaults
database: prod_db
host: db.example.com
Environment Variables
# Docker Compose style
environment:
- DB_HOST=${DB_HOST:-localhost}
- DB_PORT=5432
