Performance Testing Series — Part 1: Why Functional Testing Isn't Enough & Your First JMeter Load Test
"It passed every test case. Then 200 users logged in at once — and it fell over."
I've shipped features that sailed through functional QA. Every test case green. Every acceptance criterion met.
And then they hit production traffic and buckled.
Not because the logic was wrong. Because nobody asked the one question functional testing never asks:






