API Gateway is a fully managed front door for APIs. It handles routing, authorization, throttling, and versioning, and it pairs constantly with Lambda to build serverless APIs.
What it does on the exam
The tell is “expose a REST/HTTP API” or “serverless API” — usually API Gateway in front of Lambda. It also handles request throttling (protecting your backend), authorization (with Cognito or Lambda authorizers), and caching responses. It scales automatically and you pay per request.
Test yourself
A team wants to expose a serverless REST API that runs Lambda functions, with built-in throttling and authorization. What sits in front of Lambda?
- An Application Load Balancer only
- Amazon API Gateway
- A NAT gateway
- Amazon Route 53 alone
👉 Click to reveal the answer & explanation
Correct answer: B. API Gateway is the managed front door for serverless APIs, adding routing, throttling, and authorization in front of Lambda. An ALB (A) can invoke Lambda but lacks API Gateway’s API-management features; NAT (C) and DNS (D) don’t manage APIs.
Related topics
AWS Lambda · Amazon Cognito · Step Functions
Ready to pass the AWS Solutions Architect Associate (SAA-C03)?
Stop guessing whether you’re ready. Our full-length, exam-realistic practice exams put you through the exact question style you’ll face — with a detailed explanation behind every answer, so you learn why, not just what.
- ✓ 6 full-length practice exams
- ✓ A detailed explanation for every single question
- ✓ Realistic, scenario-based questions — not memory dumps
- ✓ Lifetime access, kept current for 2026
Get the SAA-C03 Practice Exams →or try 25 free questions first