It is our pleasure to welcome the reader to the (pre-workshop) proceedings of the 2nd International Workshop on Crowd Sourcing in Software Engineering (CSI-SE 2015), co-located with the 37th International Conference on Software Engineering (ICSE 2015) held in Florence, Italy, May 19, 2015. A number of trends under the broad banner of crowdsourcing are beginning to fundamentally disrupt the way in which software is engineered. Programmers increasingly rely on crowdsourced knowledge and code, as they look to Q&A sites for answers or use code from publicly posted snippets. Programmers play, compete, and learn with the crowd, engaging in programming competitions and puzzles with crowds of programmers. Online IDEs make radically new forms of collaboration possible, allowing developers to synchronously program with crowds of distributed programmers. Programmer reputation is increasingly visible on Q&A sites and public code repositories, opening new possibilities in how developers find jobs and companies identify talent. Crowds of non-programmers increasingly participate in development, usability testing software or even constructing specifications while playing games. Crowdfunding democratizes choices about which software is built, broadening the software which might be feasibly constructed. Approaches for crowd development seek to microtask software development, dramatically increasing participation in open source by enabling software projects to |