Hoare started working on Rust in 2006 as a hobby and Mozilla where he was working took an interest. They gave him a team of engineers and released the first version of it in 2010. Rust is targeted for frustrated C++ developers. The programming language won first place for "most loved programming language" in the Stack Overflow Developer Survey in 2016, 2017 and 2018.
Hoare "burnt out" and stepped down as technical lead in 2013. He moved to working on lower-profile and less-time-sensitive projects such as a test-farm automation for Firefox-on-Android at first; later the wifi-and-cell geolocation service. He quit Mozilla and worked for the payment network, Stellar building a distributed transaction processor for a year and a half. In early 2016, he received a call from Apple Inc to work on Swift (programming language).