Synthetic Testing
What it is
Synthetic testing (synthetic/active monitoring) is a technique that continuously generates scripted, simulated user traffic against a live application from external locations to verify availability, responsiveness, and key flows — even when no real users are online. In Azure it’s delivered by Application Insights availability tests (URL ping, multi-step, and standard tests).
Why it exists
Passive telemetry only tells you about real users’ traffic — if nobody is online during an outage, you won’t know until users complain. Synthetic testing exists to proactively verify the app is up and responding before users are impacted, by simulating requests from fixed global points on a schedule.
Key ideas
- Run tests from multiple global locations on a schedule (e.g. every 5 minutes) against URLs or multi-step flows.
- Availability tests in Application Insights: URL ping, standard test (combines request + dependency validation), and multi-step web test (a recorded user journey).
- Each test reports success/failure, response time, and location breakdown; failures can fire alerts via action groups.
- Complements passive monitoring: synthetic = proactive, telemetry = reactive/real-user.
Exam notes
- Synthetic testing = proactive availability monitoring; App Insights availability tests are the Azure implementation.
- Remember the three test kinds: URL ping (basic), standard (request + dependencies), multi-step (browser journey).
- Tests run from global locations → catches regional issues; successful results prove an endpoint is reachable and responsive, not that the app is bug-free.
- Commonly feeds status dashboards and alerts (the “is it up?” signal in the feedback loop).
Related
application-insights · azure-monitor · alerting · continuous-feedback · feedback-loop
📘 Source: Microsoft Learn — Synthetic Testing