4.4. Key Concepts Review (Developer Focus)

💡 First Principle: Active review that forces recall builds stronger memory than passive re-reading — think of this section as your pre-exam mental rehearsal, similar to how athletes visualize their performance before competition.

What if you could predict exactly which tricky distinctions the exam will test? This review section distills the most commonly confused concepts — DynamoDB GSI vs. LSI, SQS Standard vs. FIFO, Cognito User Pools vs. Identity Pools — into focused comparisons. For instance, consider the question "Which Cognito service authenticates users?" — without this review, you might confuse User Pools (authentication) with Identity Pools (AWS credential vending). Without this targeted review, candidates often confuse similar services under exam pressure.