Pebble is a project with the vision of building a key value store that allows the storage and retrieval of big data in main memory, instead of distributed systems on disk. Making simpler, faster and cheaper to access and process this data. During the presentation will be exposed the motivations behind this project and current applications. Will be described the algorithm behind the implementation of Pebble, few practical examples will be presented and future work will be discussed. Pebble is based on the work made by Paolo Boldi and Sebastiano Vigna with WebGraph. A reference to their work can be found on this paper: "Paolo Boldi and Sebastiano Vigna. The WebGraph framework I: Compression techniques. In Proc.of the Thirteenth International World Wide Web Conference (WWW 2004), pages 595−601, Manhattan, USA, 2004. ACM Press" http://vigna.di.unimi.it/ftp/papers/WebGraphI.pdf