Modern applications are expected to be available around the clock. Customers expect websites, mobile applications, payment systems, and APIs to function reliably regardless of traffic volume, geographic location, or infrastructure failures.
Consider a typical online shopping platform. During normal business hours, the application serves approximately 10,000 users. On major sale events such as Black Friday, traffic may increase tenfold within minutes. If the application becomes unavailable during this period, the organization risks losing revenue, customer trust, and brand reputation.
Historically, software development and operations teams worked independently. Developers focused on delivering features, while operations teams were responsible for maintaining infrastructure and responding to outages. This separation often created conflicting priorities:
As systems became increasingly complex, traditional operational practices were no longer sufficient. Manual server administration, reactive troubleshooting, and repetitive operational tasks created bottlenecks that prevented organizations from scaling effectively.
To address these challenges, Google introduced Site Reliability Engineering.