Introduction

Perfection is finally attained not when there is no longer anything to add, but when there is no longer anything to take away.

- Antoine de Saint-Exupéry

Falcon is a reliable, high-performance Python web framework for building large-scale app backends and microservices. It encourages the REST architectural style, and tries to do as little as possible while remaining highly effective.

Falcon apps work with any WSGI server, and run great under CPython 2.7, PyPy, and CPython 3.3+.

How is Falcon different?

We designed Falcon to support the demanding needs of large-scale microservices and responsive app backends. Falcon complements more general Python web frameworks by providing bare-metal performance, reliability, and flexibility wherever you need it.

Fast. Same hardware, more requests. Falcon turns around requests several times faster than most other Python frameworks. For an extra speed boost, Falcon compiles itself with Cython when available, and also works well with PyPy. Considering a move to another programming language? Benchmark with Falcon + PyPy first.

Reliable. We go to great lengths to avoid introducing breaking changes, and when we do they are fully documented and only introduced (in the spirit of SemVer) with a major version increment. The code is rigorously tested with numerous inputs and we require 100% coverage at all times. Six and mimeparse are the only third-party dependencies.

Flexible. Falcon leaves a lot of decisions and implementation details to you, the API developer. This gives you a lot of freedom to customize and tune your implementation. Due to Falcon’s minimalist design, Python community members are free to independently innovate on Falcon add-ons and complementary packages.

Debuggable. Falcon eschews magic. It’s easy to tell which inputs lead to which outputs. Unhandled exceptions are never encapsulated or masked. Potentially surprising behaviors, such as automatic request body parsing, are well-documented and disabled by default. Finally, when it comes to the framework itself, we take care to keep logic paths simple and understandable. All this makes it easier to reason about the code and to debug edge cases in large-scale deployments.

Features

• Highly-optimized, extensible code base
• Intuitive routing via URI templates and REST-inspired resource classes
• Easy access to headers and bodies through request and response classes
• DRY request processing via middleware components and hooks
• Idiomatic HTTP error responses
• Straightforward exception handling
• Snappy unit testing through WSGI helpers and mocks
• CPython 2.6-2.7, PyPy 2.7, Jython 2.7, and

About Apache 2.0

Falcon is released under the terms of the Apache 2.0 License. This means that you can use it in your commercial applications without having to also open-source your own code. It also means that if someone happens to contribute code that is associated with a patent, you are granted a free license to use said patent. That’s a pretty sweet deal.

Now, if you do make changes to Falcon itself, please consider contributing your awesome work back to the community.

Falcon License

Copyright 2012-2017 by Rackspace Hosting, Inc. and other contributors, as noted in the individual source code files.

Licensed under the Apache License, Version 2.0 (the “License”); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

By contributing to this project, you agree to also license your source code under the terms of the Apache License, Version 2.0, as described above.