FastAPI

FastAPI has established itself as a leading API framework, particularly popular in the ML services space due to its combination of performance, ease of use, and robust feature set. The framework excels in providing a modern, type-safe approach to API development while maintaining excellent performance characteristics.

The documentation is exceptional, offering comprehensive coverage with clear examples and explanations. The automatic API documentation generation is particularly valuable, providing interactive documentation out of the box. The framework's use of modern Python features, including type hints and async support, contributes to a robust development experience.

The community around FastAPI is very active, with regular contributions and a growing ecosystem of extensions and tools. The framework's performance is outstanding, making it particularly suitable for ML service deployment where response time is critical. The type checking capabilities help catch errors early in development.

While there is a learning curve for advanced patterns, particularly around dependency injection and complex async patterns, the investment in learning pays off through improved development efficiency and code quality. The framework's approach to background tasks, while functional, could benefit from more built-in features for complex scenarios.