Layer 3 · Go deeper · 8 min
Go deeper
Size it, build it, then make the calls an interviewer will push you on.
Back of the envelope
Size it up
Tap through each step of the arithmetic.
What does a gateway hop cost?
Can AWS API Gateway in Hyderabad take a 10:00 tatkal rush?
What do WebSocket API limits mean for a million users?
Build-up · 6 steps
From direct calls to a front door
Three clients and three services. Each step adds one job to the gateway, or keeps one out, and says why.
Step 1 of 6
Direct calls
Web, mobile and partner clients call every service directly. Each service terminates TLS, checks tokens, limits callers and logs, all in its own code.
4 interview moments
You’re the candidate
The interviewer pushes on the hard parts. Pick an approach and see how it holds up.
Deep dive 1 of 4
Interviewer
“Marketing wants coupon codes validated in the gateway, since every order passes through it. Do you agree?”
Your move. Pick an approach:
Deep dive 2 of 4
Interviewer
“Where should the JWT be verified?”
Your move. Pick an approach:
Deep dive 3 of 4
Interviewer
“Payments sometimes times out behind the gateway. What retry policy should the gateway have?”
Your move. Pick an approach:
Deep dive 4 of 4
Interviewer
“A tatkal-style sale opens at 10:00 on AWS API Gateway in Hyderabad, with 50,000 taps expected in 10 seconds. What do you do?”
Your move. Pick an approach: