Craig is the sole developer of Sparrow Wallet, a Bitcoin only desktop wallet with a focus on security, privacy and usability. His work aims to provide users with a rich interface that provides full control and transparency over their funds, while being simple enough for beginners to start and grow their understanding over time. Sparrow Wallet has a strong focus on privacy, providing users access to a number of of privacy-related technologies including coinjoin using Whirlpool. His goal remains building Sparrow on standards developed through interaction with the Bitcoin open source community.

"I see simplicity not so much as a disregard for complexity, but as a clarification of the significant." - Glenn Murcutt