Disclosed are various embodiments for securing execution of page generation code. The page generation code may be instrumented with code that facilitates monitoring of one or more resources consumed by the page generation code. Various checks relating, for example, to code size and whether exception-handling code is present may be performed. The page generation code may be executed to generate a network page in response to a request obtained from a client. One or more resource consumption limits may be enforced upon the page generation code.