1. A method comprising: in a proxy server that is configured to receive requests directed toward one or more origin servers and to distribute the requests to one or more of the origin servers for processing, loading, from a data repository, one or more first network traffic filters, wherein each of the one or more first network traffic filters comprises an executable unit of computer program code specifying processing criteria and one or more actions; while the proxy server is executing and without ending execution of the proxy server, performing one or more of: loading and initiating operation of one or more second network traffic filters; removing one or more of the first network traffic filters; reordering one or more of the first network traffic filters; receiving, at the proxy server, a network message; for a particular network traffic filter of the one or more first network traffic filters, wherein the particular network traffic filter comprises particular processing criteria and one or more particular actions: determining whether the network message satisfies the particular processing criteria; in response to determining that the network message satisfies the particular processing criteria, causing the one or more particular actions to be performed; wherein the method is performed on one or more computing devices.