Systems Correctness Practices at AWS: Leveraging Formal and Semi-Formal Methods

February 4, 2025 Volume 22, issue 6 PDF Systems Correctness Practices at AWS Leveraging Formal and Semi-formal Methods Marc Brooker and Ankush Desai AWS (Amazon Web Services) strives to deliver reliable services that customers can trust completely. This demands maintaining the highest standards of security, durability, integrity, and availability—with systems correctness serving as the cornerstone for achieving these priorities. An April 2015 paper published in Communications of the ACM, titled "How Amazon Web Services Uses Formal Methods," highlighted the approach for ensuring the correctness of critical services that have since become among the most widely used by AWS customers.21 Central to this approach was TLA+,14 a formal specification language developed by Leslie Lamport. Our experience at AWS with TLA+ revealed two significant advantages of applying formal methods in practice. First, we could identify and eliminate subtle bugs early in development—bugs that would have el ... Read full article.