yaml-rs 0.1.1

A High-Performance YAML Parser for Python written in Rust

yaml-rs

A High-Performance YAML v1.2 parser for Python written in Rust

🐍 PyPI	🐙 GitHub

Features

• The fastest YAML parser in Python (see benchmarks)
• Full YAML v1.2 spec support

Installation

Using pip:

pip install yaml-rs

Using uv:

uv pip install yaml-rs

Playground

Link: https://lava-sh.github.io/yaml-rs-online/

Example

from pprint import pprint

import yaml_rs

yaml = """\
app:
  name: service
  environment: production
  debug: false
  version: 1.3.5

  log:
    level: INFO
    file: /var/log/service/app.log
    rotation:
      enabled: true
      max_size_mb: 50

  database:
    engine: mariadb
    host: localhost
    port: 3306
    username: app_user
    password: super_secret_password
    pool_size: 10
    timeout_seconds: 30

  metadata:
    author: "John Doe"
    created_at: 2024-01-15T12:00:00Z
    updated_at: 2025-11-09T10:30:00Z
"""
pprint(yaml_rs.loads(yaml))

Comparison with other YAML parsing libraries

[!NOTE] Information current as of March 19, 2026.

YAML 1.1-oriented libraries

PyYAML

PyYAML is a parser for YAML 1.1

It does not pass the yaml-test-suite.

oyaml

oyaml is Ordered YAML: drop-in replacement for PyYAML which preserves dict ordering.

Because it is a fork of PyYAML, it has the same problems.

ryaml

ryaml is a parser with a Rust core focused on compatibility with PyYAML.

YAML 1.2-oriented libraries

ruamel.yaml

ruamel.yaml is a YAML 1.2 parser/emitter for Python.

It supports round-trip preservation of comments, sequence and mapping flow style, and mapping key order.

However, it does not pass the yaml-test-suite.

strictyaml

strictyaml is a Type-safe YAML parser and validator.

It also does not pass the yaml-test-suite.