Flask

Starlette includes an application class Starlette that nicely ties together all of its other functionality. A list of middleware to run for every request. A starlette application will always automatically include two middleware classes. ServerErrorMiddleware is added as the very outermost middleware, to handle any uncaught errors occurring anywhere in the entire stack. ExceptionMiddleware is added as the very innermost middleware, to deal with handled exception cases occurring in the routing or endpoints. Startup handler callables do not take any arguments and may be either standard functions or async functions. Shutdown handler callables do not take any arguments and may be either standard functions or async functions.

Express is a minimal and flexible Node.js web application framework that provides a robust set of features for web and mobile applications. With a myriad of HTTP utility methods and middleware at your disposal, creating a robust API is quick and easy. Express provides a thin layer of fundamental web application features, without obscuring Node.js features that you know and love. Express has no notion of a database. This concept is left up to third-party Node modules, allowing you to interface with nearly any database. In Express, 404 responses are not the result of an error, so the error-handler middleware will not capture them. This behavior is because a 404 response simply indicates the absence of additional work to do; in other words, Express has executed all middleware functions and routes, and found that none of them responded.