Synthetic Monitoring Setup: Detecting Hidden Website Problems

Ordinary ping monitoring shows HTTP 200 but doesn't notice that the login form is broken or a page loads in 10 seconds from a remote region. We've encountered this: a client was losing conversions while users complained to support. Synthetic Monitoring solves this problem — it simulates real actions: logging into an account, filling a cart, placing an order. Tests run from different geolocations every minute. This uncovers hidden failures before they impact your business. We configure synthetic monitoring turnkey: from scenario audit to dashboards and alerts. Our team has over 5 years of monitoring experience and 50+ projects.

How Synthetic Monitoring Reveals Hidden Problems

A scenario is recorded once, then run on a schedule. For example, a login test fills fields and checks for the presence of a dashboard. If a step fails (page not loaded, button not found), the system generates an alert. Thresholds are configurable: 2 consecutive failures in 5 minutes — critical, send to Slack and PagerDuty. This allows faster response than waiting for user reports.

On one project, we discovered that a server in Asia responded with TTFB of 8 seconds due to incorrect CDN configuration. Synthetic Monitoring with a Tokyo location showed this within 5 minutes after deployment. Thanks to the Slack alert, the issue was fixed before users noticed. As a result, error detection time dropped from hours to minutes.

What Ordinary Checks Miss — Synthetic Monitoring Configuration

• API timeout — ping passes, but backend returns 503.
• Broken CSS/JS — page renders incorrectly in a specific browser.
• Slow authentication — login time exceeds 5 seconds in a remote region.

These issues are invisible with standard monitoring. Synthetic Monitoring emulates a browser and measures real user experience. We use three approaches: Datadog Synthetics (cloud), Checkly (code-first), and Grafana k6 (load testing). Let's compare them.

Comparison of Tools

Datadog is convenient for quick no-code setup. Checkly is for developers who want to version control tests in git. k6 is for load testing. The choice depends on your stack and tasks.

Why Choose a Code-First Approach for Tests?

A code-first approach (Checkly, k6) integrates with your CI/CD: deploying tests with the same command as site code. No separate environment needed. Checkly provides ready integrations with Slack and PagerDuty.

// __checks__/login.spec.ts import { test, expect } from '@playwright/test'; test('Login flow works', async ({ page }) => { await page.goto('https://mysite.com/login'); await page.fill('[name="email"]', process.env.MONITOR_EMAIL!); await page.fill('[name="password"]', process.env.MONITOR_PASSWORD!); await page.click('[type="submit"]'); await expect(page).toHaveURL(/\/dashboard/); });