PyYAML

PyYAML is a YAML parser and emitter for Python. It provides utilities to parse YAML documents into Python objects and to serialize Python data structures into YAML. The library supports standard YAML features such as mappings, sequences, scalars, anchors, aliases, and tagged values, and can handle multiple documents in a single stream.

PyYAML is implemented as a Python package with optional C speedups via the libyaml project. When the C extension is available, parsing and emitting can be substantially faster, while pure-Python fallback remains compatible.

It offers functions such as safe_load and load for reading YAML, and safe_dump and dump for writing YAML. Since loading YAML from untrusted sources can execute arbitrary code when using the default loader, modern usage recommends specifying a Loader class (for example SafeLoader or FullLoader) to control evaluation and improve security.

It is released under the MIT license and is widely used in Python projects for configuration and data interchange that uses YAML.

PyYAML is maintained as an open-source project and is commonly installed via pip (pip install PyYAML).