The IoTCrawler is a project, funded by EU under the H2020 programme, whose main objective is to become a scalable, flexible and secure search engine for IoT information. Its intention is not to become a new IoT platform competing with existing ones, but being a higher frame of reference for all of them, creating an IoT ecosystem, quite like any web.based search engine is for websites and webpages. It provides scalable and efficient methods for discovery, crawling, indexing and ranking of IoT resources in large-scale cross-platform, cross-disciplinary systems and scenarios. IoTCrawler improves on other approaches by providing and considering as main driving pillars the enablers for secure and privacy-aware access of IoT resources while also, providing monitoring and analysis of QoS and QoI that is evaluated during the ranking of suitable resources and supports fault recovery and service continuity.