ECMWF is an operational centre, producing global numerical weather predictions. ECMWF also operates many services for the EU Copernicus programme . ecCharts is a suite of web based services to visualise and explore ECMWF real-time forecast. The service offers a Web Map Service (WMS) as well as an interactive client application which provides forecast data for meteorological community including Copernicus services. Recent development work involved the replacement of the client application with OpenLayers and implementing a caching system with MapProxy. This posed many challenges due to size and frequent updates of the data, combined with the challenges of offering a fast and smooth user experience. The work also resulted in contributions to open source projects, like OpenLayers, which will benefit the wider user community. This talk presents the benefits of moving to open source community software,the architecture of the updated system and on the challenges and the solutions that are taken when dealing with big and dynamic data sets both at the frontend and at the backend services.