Europeana is an evolving service that tries to be a single access point for Europe’s cultural heritage. The metadata aggregation for Europeana is a procedure that needs interoperability and software tools for transforming metadata to Europeana Semantic Elements (ESE). This aggregation imposes requirements difficult to be implemented in many small institutions. To accommodate these needs and help the Greek institutions contribute their content to Europeana, we developed a series of tools. The Hellenic Aggregator that has established a single communication point with Europeana. The Open Archives Engine (OAE) software for creating digital library aggregators. The oaipmh.com tool for validating OAI-PMH enabled repositories. Other wrappers that enable repeatable generation and harvesting of ESE-compatible metadata via OAI-PMH. We present these tools and the way that helped the Greek cultural institutions in contributing content to Europeana.