Product Updates
Python SDK Lazy Loading: 7.5x Faster Initialization, 80% Less Memory Use
Kanwar Baweja
May 27, 2025 - 2 min read
We shipped a major performance improvement to our Python SDKs.
Now, every Speakeasy-generated Python SDK will defer loading of modules until they’re actually needed — instead of loading everything upfront when the SDK is imported.
We’ve implemented this by making use of Python’s forward references and lazy loading of modules. This approach maintains full type safety and IDE autocomplete functionality while completely avoiding the performance penalty of eager imports.
Why it matters
With this update, Python SDKs will show dramatic performance improvements across two key metrics:
- 8.5x faster initialization: In a sample of large customer SDKs, import time was reduced from 1.7 seconds to just 0.2 seconds. Faster imports mean better developer experience: less waiting during development, faster CI/CD test runs, and quicker serverless cold starts
- 80% reduced memory footprint: Similarly, memory usage was cut from ~98MB to ~22MB on initial import
Performance Impact
Initialization Time Improvements
In the example below, the time taken for the import statement dropped from 1.26 sec to 0.17 sec — 7.5x faster! This improves the developer experience considerably.
Before lazy loading:
After lazy loading:
Memory Usage Reduction
The memory used by the process was reduced from 124 MB to 40MB — a 68% reduction in memory footprint.
Before lazy loading:
After lazy loading:
Performance measurements were taken using this script .
Key Benefits
- Faster Development Cycles: Reduced import times mean less waiting during development iterations
- Improved CI/CD Performance: Faster test suite execution with quicker SDK imports
- Better Serverless Performance: Reduced cold start times for serverless functions
- Lower Resource Costs: Decreased memory usage translates to lower infrastructure costs
- Maintained Developer Experience: Full type safety and IDE autocomplete functionality preserved
Technical Implementation
Our lazy loading implementation leverages:
- Python Forward References: Maintaining type hints without eager imports
- Module-level Lazy Loading: Deferring module initialization until first use
- Preserved Type Safety: Full static analysis support maintained
- IDE Compatibility: Autocomplete and IntelliSense continue to work seamlessly
Getting Started
Simply ensure your Speakeasy CLI is upgraded to version v1.549.0:
Every Python SDK generated with this version and above will incorporate these improvements automatically, and your applications will start faster and use less memory!
What’s Next
This performance improvement is just the beginning. We’re continuously working on optimizing our SDK generation to provide the best possible developer experience. Stay tuned for more performance enhancements across all our supported languages.
Try out the new lazy loading feature in your Python SDKs and experience the performance boost firsthand!