DevOps is a culture and practice in software engineering that aims to enhance cooperation and communication between IT operations teams and software development teams. In order to help teams deliver applications and updates more quickly and reliably, DevOps aims to automate the procedures and tools involved in the software development and deployment lifecycle.
SRE (Site Reliability Engineering) is a DevOps approach and discipline that concentrates on the performance, availability, and reliability of software systems. SRE teams are in charge of introducing automation and other methods to increase the reliability and efficiency of operations, as well as making sure that systems are built and run in a way that satisfies service-level goals.
DevOps and SRE differ primarily in that SRE is a discipline within DevOps that focuses on reliability and performance, while DevOps is a larger culture and practice. In other words, SRE concentrates on the operational aspects of running software systems, whereas DevOps covers the complete lifecycle of software development and deployment.