Many governments have published their data on the web with the goals of improving transparency and stimulating innovation, among others. In order to achieve these goals, users must be able to discover and understand these Open Government Data (OGD). The use of semantic annotation has been proven in previous studies to be effective in meeting this need. Yet, the process of annotating data remains an open challenge. Although efforts have been made in recent years to simplify this process, there is still a lack of semantic annotation tools that integrate well with OGD portals. To this end, we present ODSAG (Open Data Semantic Annotation and Graph), a chrome extension that can be easily interoperable with any OGD portal, automatically annotates an open dataset and creates graphs from it.