Format at a glance
- Full name
- YAML Ain't Markup Language
- File extensions
- .yaml, .yml
- MIME types
- application/yaml;charset=utf-8
- Category
- Text and data
- Compression
- Depends on the contained codec
- Transparency
- Not applicable
- Animation
- Not applicable
- Properties
Suitable tools
What is this format?
YAML means YAML Ain't Markup Language. Mappings, sequences and scalars use indentation, dashes and colons. A hash begins a comment.
YAML supports anchors, aliases, multiline strings and typed values. YAML 1.1 and 1.2 parsers can interpret certain words and numbers differently.
What is it used for?
- CI/CD and cloud configuration
- Docker Compose and Kubernetes
- Static sites and application settings
- Readable structured data files
Which programs can open it?
- Visual Studio Code and JetBrains IDEs
- yq and command-line tools
- Programming languages with YAML libraries
- Text editors with syntax validation
Support across devices and browsers
YAML opens in text editors and suitable spreadsheet, development or data tools.
TextEdit, development editors and format-specific applications can read YAML.
Text editors, command-line tools and programming libraries support YAML.
Text and data editors can open YAML, with varying validation and editing features.
Files-compatible editors and development tools can display YAML.
A browser can show the text, but correct presentation or validation requires a suitable parser.
Advantages
- Compact, commentable configuration
- Supports nested structures
- Readable with consistent formatting
Disadvantages
- Indentation errors change structure
- Versions and parsers interpret some values differently
- Complex features can be unsafe in untrusted parsers
Comparison with alternatives
JSON is stricter and more uniform; YAML is often shorter and allows comments.
TOML focuses on configuration and explicit types but becomes more verbose for deep structures.
INI is simpler but cannot represent complex nested data consistently.
LocalFileLab support
YAML is recognized as an input. Text is read locally and handled by the matching parser.
YAML is available as a local output; available settings depend on the format.
LocalFileLab can compress YAML locally or package it in a supported archive; already compressed content will not necessarily become smaller.
A complete YAML preview is not currently available.
Complete preservation of format-specific metadata is not guaranteed.
Related formats
Frequently asked questions
Can YAML use tabs for indentation?
Structure should use spaces. Tabs cause errors or unexpected behavior in many parsers.
Are YAML and YML the same?
Yes. .yaml and .yml are alternative extensions for the same data format.
Why does YAML sometimes turn yes into true?
YAML 1.1 treats several words as booleans. YAML 1.2 is narrower; exact behavior depends on the parser.