pyang

What it is and what it does

pyang is a YANG validator and code generator for network data models. YANG (RFC 7950) is a data modeling language used with NETCONF for network device configuration. pyang reads YANG modules, validates them for correctness against the YANG grammar and RFC specifications, and can transform them into other formats (YIN, DSDL schemas, UML diagrams, tree representations, XML skeletons, and JSON). It includes a plugin system for extending its output capabilities, making it suitable for both standalone validation workflows and integration into larger network automation or code-generation pipelines.

The package depends only on lxml for XML processing and is written in pure Python, making it portable across platforms. It has been actively maintained since its first release, with support for Python 3.7 through 3.11. The tool is commonly used by network engineers and automation developers who need to validate vendor or standards-based YANG models, generate documentation from data models, or translate models into formats suitable for schema validation or code generation.

Use it for:

• Validate YANG modules from network device vendors or IETF standards before deploying them in NETCONF-based automation.
• Convert YANG models to DSDL schemas for validating XML instance documents from network devices.
• Generate tree diagrams or UML visualizations of YANG data models for documentation and design review.
• Transform YANG modules to YIN (XML representation) for processing or archival in XML-based workflows.
• Build custom code generators by writing pyang plugins to emit device-specific or language-specific code from YANG models.

Worth the install?

AI-flagged interpretation of the facts on this page — verify before relying

pyang validates YANG data models (RFC 7950), converts between YANG and YIN formats, and generates code and documentation from YANG modules via a plugin framework.

Yes. pyang is a stable, actively maintained tool with no known vulnerabilities, low install friction, and a permissive license. Install it if you work with YANG models, NETCONF, or network data modeling; otherwise, it is not a general-purpose utility.

Install

pyang on PyPI

pip install pyang

uv add pyang

poetry add pyang

Installing pyang

Before you install

Low install friction; pure Python wheel with a single runtime dependency (lxml). Actively maintained with a recent release (2025-08-29) and ongoing repository activity.

License in practice

BSD permissive license allows use in most commercial and open-source projects without significant restriction.

Quickstart

pip install pyang
python -c "from pyang import context; ctx = context.Context()"

Verify before relying

• Whether the plugin framework is documented well enough for custom code generation without reading source code.
• Performance characteristics when validating large or deeply nested YANG modules.
• Whether all IETF RFCs listed (RFC 6020, 6087, 6110, 6643, 7950, 7952, 8040, 8407, 8791, 9595) are fully implemented or partially supported.

Package facts

Evidence: pyang-2.7.1-py2.py3-none-any.whl

Keywords: YANG, validator

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