This presentation will discuss enterprise web mapping applications that we've been developing for large utilities and communications companies, based on a number of open source geospatial components. At this time last year the main elements of our solution were PostGIS, MapFish and Google Maps. Since then we've added GeoServer into the mix, and we're just finishing a migration from Google Maps to Leaflet on the front end (but still able to pull in data from Google as well as OpenStreetMap, Bing and other sources). We'll talk about examples of what our customers have been doing, including how we helped one of them with recovery from Hurricane Sandy, and how we're handling some very large volumes of near real time data from cable networks using PostGIS and GeoServer. And we'll talk about various technical architecture issues including our approach to offline mobile web applications on various platforms, our experience of moving to Leaflet, and best practices on updating PostGIS with large volumes of near real time data.