This document introduces SAE Python, a sandboxed environment for running Python web applications on Sina App Engine. It discusses how the sandbox limits processes, networking, and file system access for security. The sandbox approach aims to be pragmatic by allowing unmodified application code while restricting potentially dangerous operations. SAE Python supports popular Python web frameworks and provides additional services like MySQL, memcache, and task queues. It uses Apache and mod_wsgi to host applications in an embedded or daemon mode. The document compares SAE Python to other Python hosting providers and outlines roadmap items like Git support and an internal PyPI server.