Algorithms govern almost every facet of our daily lives. Personalized flows of data are generated by black boxes that we cannot interrogate, but that can significantly influence our decisions about what to buy, where to live or work, with whom to interact, and even what to believe. The Algorithmic Transparency Initiative (ATI) seeks to improve the transparency of algorithms that shape society by providing tools and data that can be leveraged by all to hold the powerful accountable. ATI develops tools, methodologies, data sets, and investigations that support research and journalism about digital platforms with a commitment to the highest ethical standards of research, data collection, and user privacy. We are equipping everyone to contribute to this effort through tools to help shed light on these powerful technologies.