7.5Designing Effective Synthetic Tests

What to Monitor

Journey	Priority	Frequency	Timeout
Homepage load	Critical	Every 1 min	10s
User login	Critical	Every 2 min	15s
Product search	High	Every 5 min	15s
Add to cart	High	Every 5 min	15s
Checkout flow	Critical	Every 5 min	30s
API health endpoints	Critical	Every 30s	5s

Best Practices

1. Use dedicated test data. Create a "synthetic-test-product" that is always in stock, never on sale, and easily identified in analytics filters.

2. Tag synthetic traffic. Add a header or query parameter (?synthetic=true) so analytics and billing systems can filter out synthetic activity.

3. Run from multiple regions. A test passing in us-east-1 and failing in ap-south-1 immediately identifies regional issues.

4. Keep tests simple. Synthetic tests should be the simplest possible path through a critical flow. Complex multi-branch test logic belongs in CI, not in production monitoring.

5. Set aggressive timeouts. If a checkout flow takes more than 30 seconds in production, it is effectively broken regardless of whether it eventually succeeds.

6. Capture screenshots on failure. Attach screenshots to alert payloads so the on-call engineer can see what the user would see.