Synthetic Monitoring Best Practices: What to Monitor and How Often

Most synthetic monitoring setups fail in one of a few predictable ways. They monitor everything and alert on nothing useful. They assert on status code 200 and miss the empty response body. They run flaky browser checks that page someone at 2 AM for a problem that fixed itself by 2:01. Or they go stale — the checkout flow changed three months ago and the check has been failing-then-being-ignored ever since. These are not exotic failures. They are the default outcome of setting up synthetic monitoring without a discipline. Here is the discipline. 1. Monitor the journeys that cost money, not everything Every browser check costs compute and, more importantly, costs maintenance. A check on a path that does not matter is worse than no check — it generates noise that trains your team to ignore alerts. Rank your journeys by cost of silent failure and monitor the top of the list: Authentication — login, signup. The gate to everything else. The revenue path — checkout, upgrade, add payment method. The core product action — the one thing your product exists to do. Critical third-party handoffs — OAuth redirects, payment iframes, SSO. Leave static pages, read-only endpoints, and admin screens to cheaper uptime and API checks . A good rule: if a path breaking would not generate a support ticket or lose revenue, it does not need a browser check. 2. Assert on what the user sees, not just the status code The entire point of synthetic monitoring is catching the failure that a 200 OK hides. So your assertions have to go past the status code. // Weak: passes even when the page renders an error await page . goto ( " https://shop.example.com/checkout " ); expect ( page . url ()). toContain ( " /checkout " ); // Strong: asserts the user can actually complete the action await page . getByRole ( " button " , { name : " Pay now " }). click (); await expect ( page . getByText ( " Order confirmed " )). toBeVisible ({ timeout : 10000 , }); await expect ( page . getByTestId ( " order-number "