CircleCI is a continuous integration (CI) and continuous delivery (CD) platform that can be used to implement DevOps practices. The company was founded in September 2011 and has raised $315 million in venture capital funding as of 2021, at a valuation of $1.7 billion. CircleCI is one of the world's most popular CI/CD platforms. Facebook, Coinbase, Sony, Kickstarter, GoPro, and Spotify used CircleCI in 2019.