A site reliability engineer (SRE) is a software engineering discipline that combines software development with systems administration. The main goal of an SRE is to create and maintain a scalable and highly available system. 

SREs are responsible for ensuring that a company’s website or service is always up and running. They do this by monitoring the site or service for any problems and then fixing them as quickly as possible. In addition to monitoring and fixing problems, SREs also work on improving the site or service to make it more reliable.

SREs use a variety of tools to do their job, including monitoring tools, logging tools, and configuration management tools. They also use scripting languages such as Python and Ruby to automate tasks.