RERO, the Library Network of Western Switzerland, provides several library-oriented web and non-web services to its members. In 2013, we felt the need for a more powerful search engine for our digital library (RERO DOC). This service is based on an open source product called Invenio. After several months of integration, Elasticsearch enabled us to introduce new features such as hierarchical facets and search term highlighting. Since then, this tool has been used for other purposes in our organization, such as log analysis and web site usage statistics. This presentation explains how Elasticsearch has been successfully integrated into our systems.