Day 37 of 60
·
Production & continuous
Real-user monitoring + error tracking
Your dashboards measure your servers. RUM measures your users; and the gap between the two is where churn happens silently.
ProblemYou see what monitoring measures; you don't see what users experience.
How it works
Browser/SDK telemetry capturing real user latency, errors, and Core Web Vitals. Error tracking aggregates exceptions with stack traces.
What it catches
Real-user errors, performance regressions on real devices, browser-specific issues, regional latency.
Tools
Sentry · Hybrid Datadog RUM · SaaS GlitchTip · OSS
Verdict by project size
Small
Must
Medium
Must
Large
Must
Extra-large
Must
Cost
| Project size | Setup | Maint / mo | Tool / mo | CI / run |
|---|---|---|---|---|
| Small <10k LOC | 2h | 1h | $0 | , |
| Medium 10–100k LOC | 1d | 3h | $200 | , |
| Large 100k–1M LOC | 3d | 10h | $2k | , |
| Extra-large >1M LOC | 10d | 30h | $10k | , |
Setup = engineer-days to first useful run ·
Maint = engineer-hours / month at steady state ·
Tool = out-of-pocket $ / month ·
CI = minutes added (or saved) per pipeline run
Lifecycle & ownership
When in lifecycle
Release Operate Observe
Continuous in prod · Always-on, observing real traffic.
Who owns it
SRE / DevOps / Platform
CI/CD, observability, reliability
Collaborates with: Developer
Reference implementations
-
Sentry examples
Reference apps for error tracking and real-user telemetry capture.
-
OpenTelemetry JS browser example
Browser and Node telemetry examples for real-user instrumentation.
-
Elastic RUM examples
Frontend real-user monitoring examples with page-load and route-change tracing.
Quick check
Real-user monitoring (RUM) closes which observability gap?
One question. Pick the best answer. Your streak is saved locally on this device.
Save the lesson
Download SVG ↓
Screenshot for a 1:1, drop it in Slack, or download the SVG.