Synthetic Monitoring
Definition
Proactive monitoring that simulates user interactions on a schedule to verify pages load and APIs respond before real users notice an outage.
Use Cases
- Amazon: Detecting checkout and login regressions before customers are impacted during high-traffic events — Teams run scheduled synthetic transactions that simulate critical paths (sign-in, add-to-cart, checkout) from multiple regions, alerting on step failures and latency thresholds and correlating with logs/metrics for rapid triage (Earlier detection of customer-impacting issues, reduced mean time to detect (MTTD), and improved reliability of critical revenue paths during peak traffic)
- Netflix: Validating service availability and playback-related APIs across regions to catch outages and routing issues early — Engineers use automated probes and synthetic requests to key APIs from multiple locations, combining results with observability data to identify regional failures and dependency problems (Faster identification of regional or dependency-related incidents and improved confidence in service health across global deployments)
- GitHub: Monitoring availability and performance of core web and API endpoints to detect incidents quickly — Runs continuous endpoint checks and synthetic requests against critical user-facing and API routes, alerting on error rates, latency, and availability anomalies and linking to incident response workflows (Improved incident detection and response for critical developer workflows, helping reduce downtime impact)
Provider Equivalents
- AWS: Amazon CloudWatch Synthetics
- Azure: Azure Monitor Application Insights availability tests
- GCP: Google Cloud Monitoring uptime checks
- OCI: OCI Monitoring (HTTP checks via external probes) / OCI Application Performance Monitoring (synthetic monitoring capabilities vary by region/service)
Frequently Asked Questions
- What's the difference between synthetic monitoring and real user monitoring (RUM)?
- Synthetic monitoring uses scripted tests that run on a schedule from known locations, so you can catch problems even when no one is using your app. Real user monitoring (RUM) measures what actual users experience in their browsers or apps (real devices, real networks). Synthetic is great for early warning and testing critical flows; RUM is best for understanding real-world performance and user impact.
- When should I use synthetic monitoring?
- Use it when you need proactive detection of issues on critical paths like login, search, checkout, or key APIs. It’s especially useful after deployments, during peak events, for SLAs/SLOs, and when you want coverage from multiple regions. It’s also a good fit for monitoring third-party dependencies (payment gateways, identity providers) with controlled, repeatable tests.
- How much does synthetic monitoring cost?
- Cost usually depends on (1) how often tests run (every minute vs every 5–15 minutes), (2) how many locations/regions you run from, (3) whether you use simple HTTP checks or full browser journeys, and (4) data retention and alerting/observability ingestion. Browser-based tests are typically more expensive than basic uptime checks because they run longer and collect more artifacts (screenshots, HAR files, logs). To control cost, monitor only critical journeys, run less frequently outside business hours, and keep test scripts efficient.
Category: monitoring
Difficulty: intermediate
Related Terms
See Also