--- title: "API observability: find the problem and prove the fix | Speedscale" description: "Metrics, logs, and traces tell you where to look. API traffic shows the request, response, and dependency behavior that caused the failure. These guides connect the two." canonical: "https://speedscale.com/blog/category/observability/" --- Observability guides # API observability: find the problem and prove the fix Metrics, logs, and traces tell you where to look. API traffic shows the request, response, and dependency behavior that caused the failure. These guides connect the two. Start here ## How the layers of production visibility fit together [![From Telemetry to Traffic](https://speedscale.com/_astro/featured-image.DjcDKQ-v_1jdGEf.webp)](https://speedscale.com/blog/from-telemetry-to-traffic/) ### [From Telemetry to Traffic](https://speedscale.com/blog/from-telemetry-to-traffic/) Compare eBPF, sidecars, telemetry agents, OpenTelemetry, APM, and proxies through an evolving ladder of production visibility. [Read the guide](https://speedscale.com/blog/from-telemetry-to-traffic/) ## Choose what you need to do ### Understand the gap Learn what metrics, logs, traces, and traffic each reveal about a production problem. * [The Observability Gap: Why Monitoring Data Should Drive Tests](https://speedscale.com/blog/the-observability-gap/) * [The Three Pillars Were Built for Humans](https://speedscale.com/blog/three-pillars-were-built-for-humans/) * [Five things your logs will never tell you](https://speedscale.com/blog/five-things-your-logs-will-never-tell-you/) ### Diagnose a live problem Follow practical workflows for latency, retries, and failures across service boundaries. * [Diagnose Serial N+1 API Calls With Tempo + proxymock](https://speedscale.com/blog/diagnose-n-plus-one-tempo-proxymock/) * [Explain Non-CPU Latency With Prometheus + proxymock](https://speedscale.com/blog/explain-non-cpu-latency-prometheus-proxymock/) * [Separate Application Latency From Network Failure With Hubble](https://speedscale.com/blog/separate-app-latency-network-failure-hubble-proxymock/) ### Turn findings into tests Carry production evidence into repeatable tests that run before the next release. * [From Datadog to CI Tests: Catch Regressions Before Deploy](https://speedscale.com/blog/from-datadog-to-test-suite/) * [Replace API Synthetics with Traffic Replay](https://speedscale.com/blog/replace-api-synthetics-with-traffic-replay/) * [OpenTelemetry Trace Testing for CI Release Gates](https://speedscale.com/blog/otel-trace-testing-ci-release-gates/) ## All observability articles Sep 14, 2026 ### [eBPF: Correlating rustls Plaintext to TCP Connections Without a File Descriptor](https://speedscale.com/blog/ebpf-rustls-plaintext-tcp-correlation/) Follow an eBPF debugging trail through rustls, Tokio inlining, and an empty map to learn how TLS plaintext gets matched to the right TCP connection. Sep 11, 2026 ### [Five Ways to Use OpenTelemetry Beyond Observability](https://speedscale.com/blog/opentelemetry-beyond-observability/) Teams run inventory, security logs, request routing and billing through OpenTelemetry. Five non-observability uses, and the failure mode of each. Aug 27, 2026 ### [Your Observability Stack Found the Fire. Congratulations.](https://speedscale.com/blog/your-observability-stack-found-the-fire/) Observability tells you when production is on fire. Capturing and replaying real traffic lets you recreate the incident, verify the fix, and keep it fixed. Aug 19, 2026 ### [Reliability Engineering in the AI Era](https://speedscale.com/blog/drop-the-site/) See why reliability engineering must span code, testing, telemetry, and incidents as AI agents erase the boundary between pre-production and production. Aug 13, 2026 ### [Reproduce A Rare Retry Path With Loki + proxymock](https://speedscale.com/blog/reproduce-rare-retry-path-loki-proxymock/) Find the rare payload that sends a service down a retry path, correlate it to the recorded response, and prove the fix with proxymock replay. Aug 13, 2026 ### [Synthetic Monitoring Is Broken. Your Production Traffic Can Fix It.](https://speedscale.com/blog/synthetic-monitoring-is-broken-production-traffic-can-fix-it/) Synthetic monitoring depends on scripts engineers maintain by hand. Capturing and replaying real production transactions turns customer behavior into tests. Aug 12, 2026 ### [Observe Opaque Services With OpenTelemetry eBPF + proxymock](https://speedscale.com/blog/observe-opaque-service-opentelemetry-ebpf-proxymock/) Discover endpoints, RED metrics, and traces in an opaque Kubernetes service with OpenTelemetry eBPF Instrumentation, then replay traffic with proxymock. Aug 11, 2026 ### [The Pod Was Cheaper. The Service Wasn’t.](https://speedscale.com/blog/the-cheaper-pod-cost-more/) Use OpenCost and proxymock to prove Kubernetes rightsizing lowers cost per successful request without hiding behavior or throughput regressions in testing. Jul 31, 2026 ### [Flamegraphs Find It. Replay Proves It.](https://speedscale.com/blog/flamegraphs-find-it-replay-proves-it/) Use Grafana Pyroscope and proxymock with an AI coding agent to find a Go CPU hotspot, preserve API behavior, and verify the performance fix. ## Go from alert to reproducible test Capture the API traffic behind a production issue, replay it safely, and verify the fix against the same behavior. [Start Free Trial](https://app.speedscale.com/signup) [See API Observability](https://speedscale.com/features/api-observability/)