Europe is covered by a few thousand GNSS stations, maintained by different agencies with different technical and scientific objectives. Many of these are part of regional networks to provide support for geo-referencing applications such as surveying. One of the objectives of the European Plate Observing System (EPOS) project is to collect all these GNSS data, perform quality control, harmonize formats and present the data and their derived products at dedicated data & product portals, see https://www.epos-ip.org/tcs/gnss-data-and-products, all in close collaboration with EUREF. We present here the efforts carried out by C4G/UBI in the framework of the EPOS project to support the harmonization and dissemination of products: position time series, velocity fields, and strain rate maps.