Compare
YAML vs TOML
YAML and TOML are both text formats used for human-edited configuration. YAML supports flexible hierarchical structures; TOML emphasizes explicit, readable settings with keys and tables. Choose for the tool and data shape.
Which format should you choose?
Use YAML when a tool requires it or the configuration needs complex nesting. Consider TOML for straightforward application settings with clear tables and types.
Good fit for YAML
Configuration files and structured-data authoring
- Settings maintained by people
Good fit for TOML
Application and tool configuration
- Readable settings with structured values
Basic information
| Field | YAML | TOML |
|---|---|---|
| Extension | .yaml, .yml | .toml |
| MIME type | application/yaml | application/toml |
| Common uses | Configuration files and structured-data authoring | Application and tool configuration |
| How to open | Open it in a text editor or YAML-aware tool and preserve space indentation. | Open it in a text editor or configuration-aware editor. Check the application's documentation for supported TOML features. |
| Export or convert | When the recipient requires JSON, convert it and check value types and character encoding. | When converting from JSON or YAML, verify nesting, arrays, string quoting, dates, and value types after parsing. |
Choose by use case
Settings maintained by people
Configuration files and structured-data authoring
YAMLReadable settings with structured values
Application and tool configuration
TOMLKey point 1
YAML supports rich hierarchical representations, but indentation and implicit type rules need care.
More on the differencesKey point 2
TOML uses explicit key-value and table syntax designed for configuration readability.
More on the differencesMore on the differences
Follow the target tool's supported format and version. Validate files with the actual parser and schema, especially dates, numbers, nested data, and whitespace-sensitive syntax.
- YAML is common in infrastructure and automation tools that expect YAML.
- TOML can make application settings easier to scan, but it is not accepted by every YAML-based tool.
- Both formats can be misinterpreted if parser settings or type rules differ.
Frequently asked questions
Is TOML simpler than YAML?
For many straightforward configuration files it can be, but tool requirements and data structure decide. Use the format your application reliably supports.