What Is Synthetic Testing? How It Works and Why It Matters

Last updated: October 2026

Quick answer

Synthetic testing (also called synthetic monitoring) runs scripted user journeys against a live website or API on a schedule, from outside your network, whether or not real users are on the site. A script signs in, searches or checks out the way a customer would, and records whether each step worked and how long it took. Because the same journey runs the same way every time, you get early warning of outages and slowdowns, a clean baseline for SLAs, and coverage at night or before a launch when there is no real traffic.

How synthetic testing works

1. Script a journey. Record or write the steps of a critical flow, such as login, search, add to cart and checkout, including checks on what should appear.
2. Schedule it. Choose how often it runs (for example every 5 or 15 minutes), from which locations, in which browsers and with which test data.
3. Run it in real browsers or as API calls. Each step is timed and verified: status codes, page content and functional outcomes, not just whether a page loaded.
4. Alert and analyze. When a step fails or crosses a performance threshold, the team is alerted with step-level timings and screenshots, and dashboards show trends over time.

Synthetic testing vs uptime checks

A basic uptime check pings a URL and confirms it responds. Synthetic testing goes further: it completes real tasks, so it catches a checkout button that does nothing, a login that loops, a search that returns the wrong results or a payment step that times out, even when every page still returns 200.

Five reasons teams use synthetic testing

1. Catch problems before customers do

Journeys run around the clock, so failures after a deploy, a configuration change or a third-party outage are spotted within minutes rather than reported by users.

2. Measure and prove SLAs

Consistent, scripted runs produce comparable availability and response-time numbers, which you can use to validate your own SLAs and those of the third-party services you depend on.

3. Monitor during quiet and peak periods

Synthetic tests do not need real traffic. They cover overnight hours, low-traffic regions and pre-launch environments, and they show how performance changes during peak periods.

4. Benchmark across locations and browsers

Running the same journey from several regions and browsers reveals CDN, DNS and hosting issues that only affect some users.

5. Test APIs and B2B web services

Synthetic API checks verify the REST and SOAP services that partners and front-end apps rely on, and they can be chained with browser steps so one journey covers the UI and the services behind it.

Synthetic testing vs real user monitoring (RUM)

Synthetic testing answers “is it working, and how fast?” with a controlled, repeatable baseline. Real user monitoring answers “what did actual visitors experience?” across their real devices, networks and paths. Synthetic tests catch issues proactively, even with no traffic; RUM shows the long tail you did not script. Most teams use both. Read more in synthetic monitoring vs real user monitoring.

How to choose a synthetic testing tool

• Easy journey creation. Recording in the browser, with visual editing, means non-developers can build and update journeys.
• Real browsers and modern web support. JavaScript-heavy pages, single-page apps, iframes and dynamic elements should work without custom code.
• Multi-step and data-driven journeys. Reusable steps such as login, and the ability to run one journey with different data sets.
• Low false-alarm rate. Clear step-level detail and screenshots so the team can tell a real outage from a test problem.
• Locations, schedules and alerts. Frequent runs from the regions you serve, with alerts to email, SMS, Slack or PagerDuty, and maintenance windows.
• API checks. REST calls alongside browser steps.
• Reuse of existing tests. Being able to schedule the same journeys you already use for regression testing saves a lot of work.

Synthetic testing with CloudQA

CloudQA Synthetic Monitoring replays your critical journeys in real Chrome and Firefox browsers on a schedule, from multiple locations, using the same codeless recorder as CloudQA regression tests. Each run gives step-level timings and screenshots, with alerts to email, SMS, Slack and PagerDuty. Synthetic monitoring is set up with our team for CloudQA customers. See how CloudQA synthetic monitoring works.