PyYAML
Python library for YAML serialization and deserialization.
- Status
- Generally available
- Last checked
- Aging · Sep 2, 2026
- License
- Open source
- Pricing
- Free tier · from $0
What it is
PyYAML is a Python library that allows developers to serialize and deserialize data in YAML format, making it easier to work with configuration files and other structured data.
PyYAML stands out for its comprehensive support of the YAML specification and its inclusion of a safe loader to enhance security when handling untrusted input.
When it fits — and when it doesn’t
A good fit for
Developers working with YAML-formatted data who need a reliable and efficient library for serialization and deserialization.
Projects requiring safe loading of YAML files to prevent security vulnerabilities.
Look elsewhere if
Applications that require real-time streaming or processing of YAML data
Scenarios where performance is critical, as PyYAML may not be the fastest option available
Known weaknesses
Each one links to the public issue, changelog or docs page it came from, where we have one.
- 01
Frequent breaking changes between versions
Historical version updates have introduced significant changes that require substantial code adjustments.
- 02
Limited error messages and debugging support
Error messages can be vague, making it difficult to diagnose issues with YAML parsing or serialization.
- 03
Performance overhead for large data sets
PyYAML's parser may introduce performance bottlenecks when dealing with very large YAML files or complex structures.
What it does well
Supports YAML 1.2 specification
Provides both dumping and loading functionalities for YAML data
Offers a safe loader to prevent arbitrary code execution
Pricing
- Free tier
- YesOpen source — free to use
- Paid from
- $0
- Model
- Flat rate
- Enterprise plan
- No
Pricing not independently confirmed — check the vendor’s page.
Performance benchmarks
How Fast Is It?
Set up PyYAML
Setup steps, common gotchas and what to check after 30 days.