Interview Prep
AWS interview questions and how to answer them
AWS interviews cover a lot of ground. The questions that trip people up are the ones about IAM, VPC networking, and how to choose between services with overlapping capabilities. These reflect what cloud and backend interviews actually ask.
PrepVault surfaces the questions you need and keeps your study guides organized. Free to start.
AWS interview questions and how to answer them
A team reports a sudden S3 cost spike. How would you investigate and reduce the cost safely?
Break down cost drivers. Check versions and multipart uploads. Review request patterns. Apply safe lifecycle controls
How do On-Demand, Reserved Instances, Savings Plans, and Spot Instances differ?
On-Demand flexibility. commitment discounts. Spot interruptions. mixed strategy
How does CloudFormation rollback behavior work?
rollback to stable state. resource-specific limits. events reveal root cause. stateful resource caution
What is IAM and why is the principle of least privilege important in AWS?
IAM users, groups, roles, policies. least privilege = minimum needed. roles for services, users for humans. policies are JSON allow/deny rules
What are IaC best practices for team workflows?
version control. change previews. policy checks. drift detection
How does IAM policy evaluation order work when multiple policies apply?
explicit Deny always wins. default is implicit deny. SCPs apply before identity and resource policies. permissions boundaries limit maximum permissions
What are the main sections of a CloudFormation template?
Resources required. Parameters customize. Conditions control creation. Outputs expose values
How should leadership evaluate IAM risk and maturity?
federation coverage. active access keys. privileged roles. external findings
How would you handle an accidental data deletion on an RDS production database?
Stop further damage. Find deletion time. Restore separately. Validate before cutover
How does the SNS fan-out pattern with SQS work?
One publish many queues. Independent consumers. Failure isolation. Filter policies optional
Common mistakes
- Naming services without knowing when to use them
- Fuzzy on IAM and VPC basics
- Ignoring cost in the design
What interviewers weigh
- Choosing between overlapping services
- A grasp of IAM and networking
- Cost-aware decisions