Monitoring & Observability

APM logging and system monitoring

Monitoring and observability are the practices and tooling through which engineering teams understand what their systems are doing in production. While the terms are often used interchangeably, they describe related but distinct concepts. Monitoring typically refers to tracking known failure modes through predefined dashboards and alerts. Observability — a property of the system itself — refers to the ability to understand the internal state of a system from its external outputs, enabling engineers to diagnose novel problems they did not anticipate when writing the code. The three pillars of observability are metrics, logs, and traces. Metrics provide numerical time-series data — request rates, error percentages, CPU utilisation — that are efficient to store and query at scale. Logs capture discrete events with contextual detail, invaluable for root cause analysis but expensive to index at high volume. Distributed traces connect individual requests across multiple microservices, making it possible to understand exactly where latency is introduced or where errors originate in a complex, distributed system. Modern observability platforms unify these three signals and correlate them, allowing engineers to move rapidly from alert to root cause. UK engineering leaders are prioritising observability investment for several reasons. Cloud-native architectures have dramatically increased system complexity: a single user request may traverse dozens of services, each independently deployable and operated by a different team. In this environment, traditional monitoring approaches — checking whether a server is up and its CPU is below 80% — are wholly inadequate. Mean time to detect (MTTD) and mean time to resolve (MTTR) are key operational metrics, and observability tooling is the primary lever for improving them. For UK regulated industries, observability platforms also support compliance and incident reporting obligations. Financial services firms must demonstrate they can detect, respond to, and report operational incidents within defined timeframes. Healthcare technology providers must maintain audit trails of system behaviour for clinical and regulatory review. When evaluating monitoring and observability platforms, assess the quality of automatic instrumentation (reducing the burden on developers to add telemetry), the scalability of the ingestion and querying layer (particularly under traffic spikes when you most need it), alerting flexibility and noise reduction capabilities, integration with incident management workflows, and total cost at your data volume. OpenTelemetry compatibility has become a significant selection criterion, as it protects against vendor lock-in by standardising how telemetry is emitted from applications and infrastructure.