This document describes the ECharts for SIP Servlets (E4SS) framework and development kit. E4SS makes use of the ECharts programming language as an alternative programming model built on the SIP Servlet API defined by the Java Community Process. Instead of overriding servlet methods and managing sessions, the programmer defines the application in terms of feature boxes, SIP message ports, and state-machine logic specified in the ECharts language. The use of ECharts to specify application logic greatly encourages component re-use and manages complexity, making it well-suited for Back-to-Back User Agent applications. Such applications can be composed with one another and with suitable proxy applications in order to provide feature-rich services while maintaining feature modularity, through use of a SIP Servlet Application Router. This document explains the E4SS framework abstractions and provides example-driven descriptions of the tools and libraries included with the E4SS development kit. The document also provides instructions on how to configure two common SIP containers, SailFin and OCCAS, for use with E4SS.