Distributed systems are software systems composed of multiple components. Often running on different machines or in different locations, they work together as a single system. Each part has its own job, its own data, and sometimes its own failures, but the goal is for everything to behave consistently for the user.
Think of it as a team rather than a solo act. Services communicate over networks, share responsibilities, and rely on each other to deliver features, process data, or keep things running smoothly. This can bring benefits such as scalability, flexibility, and resilience. But it can also introduce new challenges, such as latency, network failures, data consistency, and cross-service coordination.
Systems become distributed for several reasons. Sometimes it’s about scale. One machine can’t handle the load, so the work is spread out. Sometimes it’s about performance and keeping parts of the system closer to the user. Reliability plays a role. If one component fails, others should be able to step in. Teams also build systems apart so they can build, deploy, and change things independently without tripping over each other. Then there’s the modern reality of third-party software growth. Payments, identity, messaging, analytics, shipping, search… many features rely on external services we don’t own or control. The moment we integrate with them, our system becomes distributed across organisational and technical boundaries.
For testers and Quality Engineers, understanding distributed systems means asking useful questions about how components interact, what happens when one part slows down or fails, and how to observe the system as a whole. It’s all about shining a light into the gaps between services, where some of the most interesting risks and bugs tend to live.
Think of it as a team rather than a solo act. Services communicate over networks, share responsibilities, and rely on each other to deliver features, process data, or keep things running smoothly. This can bring benefits such as scalability, flexibility, and resilience. But it can also introduce new challenges, such as latency, network failures, data consistency, and cross-service coordination.
Systems become distributed for several reasons. Sometimes it’s about scale. One machine can’t handle the load, so the work is spread out. Sometimes it’s about performance and keeping parts of the system closer to the user. Reliability plays a role. If one component fails, others should be able to step in. Teams also build systems apart so they can build, deploy, and change things independently without tripping over each other. Then there’s the modern reality of third-party software growth. Payments, identity, messaging, analytics, shipping, search… many features rely on external services we don’t own or control. The moment we integrate with them, our system becomes distributed across organisational and technical boundaries.
For testers and Quality Engineers, understanding distributed systems means asking useful questions about how components interact, what happens when one part slows down or fails, and how to observe the system as a whole. It’s all about shining a light into the gaps between services, where some of the most interesting risks and bugs tend to live.
