Open 311 is an Open Application Programming Interface (API) that specifies a technical standard for service requests in municipal governments. It represents an innovation in the 311 systems, one-stop centers for managing non-emergency customer calls. The customer requests are routed to the appropriate department seamlessly through citizen relationship management (CiRM) systems. Although a technical standard, the Open 311 has profound organizational impacts on municipal governments. The Open 311 has enhanced the capabilities of the traditional 311 call centers, as well as enabled the diffusion of 311 services to those cities without such call centers. In this chapter, we examine this diffusion of Open 311 innovation among municipal governments (cities and counties). The main question is: What are the attributes of Open 311 that have contributed to its diffusion among municipal governments?.