So you've got an AWS interview coming up? I remember my first AWS technical screen years ago - totally bombed it because I underestimated how deep they'd dive into VPC configurations. Since then, I've been on both sides of the table: answering AWS interview questions as a candidate and asking them as a hiring manager. Let me tell you, most guides out there miss what actually happens in real interviews.
Breaking Down AWS Interviews
Forget cookie-cutter advice. AWS roles aren't all the same, and neither are the interviews. I've seen brilliant architects freeze up on basic troubleshooting questions, and junior devs shine because they prepared for the right things. Here's what matters:
Reality check: Only 30% of candidates pass AWS technical interviews on first attempt according to hiring managers I've talked to. Why? Because they memorize definitions instead of understanding flows.
| Role Type | What They REALLY Test | Common Mistakes |
|---|---|---|
| Solutions Architect | Cost vs performance trade-offs, disaster recovery designs, limitation awareness | Not knowing service limits (e.g. DynamoDB partition throughput) |
| DevOps Engineer | CI/CD pipeline debugging, infra-as-code nuances, monitoring under load | Can't explain CloudFormation vs Terraform differences practically |
| Cloud Support | Troubleshooting methodology, reading CloudWatch logs, network isolation | Not structuring diagnostic approach logically |
Last month I interviewed someone who claimed AWS expertise but couldn't explain when to use S3 Standard-IA vs Glacier. Don't be that person.
Core Technical Domains You Must Master
Through trial and error (mostly error), I've found these areas come up in nearly every AWS job interview:
| Domain | Why It Matters | Sample AWS Interview Question |
|---|---|---|
IAM & Security |
Everything starts with permissions | "How would you restrict S3 bucket access to specific IAM roles AND IP ranges?" |
VPC Networking |
Mess this up and nothing works | "Why can't my EC2 instance in private subnet reach the internet despite having NAT gateway?" |
Compute Services |
Foundation of everything | "When would you choose Fargate over EC2 for ECS clusters?" |
Storage Tiers |
Cost optimization hotspot | "Describe lifecycle policy for 50TB video archive accessed quarterly" |
My screwup moment: During my first AWS cloud engineer interview, they asked how to migrate 200GB MySQL DB with minimal downtime. I went straight to DMS without considering schema conversion complexities. Got schooled about AWS SCT that day.
Behavioral Questions That Trip People Up
Everyone prepares for technical AWS interview questions, then gets blindsided by behavioral ones. From what I've seen, these cause more fails than coding tests:
Interviewer confession: When I ask "Describe a cloud project failure", I'm listening for ownership language not excuses. Blaming AWS outages? Instant red flag.
❌ Bad response: "Our S3 billing exploded because AWS pricing is confusing"
✅ Strong response: "We enabled S3 analytics after 40% cost overrun and discovered misconfigured lifecycle policies. Now we enforce tags for cost allocation..."
AWS STAR Method Framework
The STAR method works but needs AWS-specific tweaks:
| Component | AWS Adaptation | Real Example |
|---|---|---|
| Situation | Name specific AWS services involved | "Our Lambda-based image processor..." |
| Task | Quantify cloud impact | "...was timing out with 30MB files" |
| Action | Detail CLI/SDK/config steps | "We moved processing to Step Functions..." |
| Result | Show metrics & cost savings | "...reducing errors by 85% and saving $1.2k/month" |
Scenarios From Actual AWS Interviews
These aren't hypothetical - I've seen variations in real interviews:
Scenario 1: "Our production PHP app on EC2 has intermittent 500 errors. CloudWatch shows normal CPU. Where do you start?"
Most candidates jump to check Apache logs (not wrong). But strong candidates:
- Ask error patterns (timing? user actions?)
- Check ALB access logs for 5xx distribution
- Verify PHP-FPM process saturation
Scenario 2: "Design voting app for 100k daily users. Must prevent fraud."
Basic answers suggest Cognito + DynamoDB. Better answers:
- Propose Lambda@Edge for geo-verification
- Use DynamoDB Accelerator (DAX) for read spikes
- Discuss CloudFront signed URLs vs token authorization
Warning: Interviewers HATE textbook answers. If you say "use auto scaling" without mentioning cool-down periods or custom metrics, you sound like you memorized FAQs.
Whiteboarding Exercises Demystified
From my experience, these cause the most panic:
| Exercise Type | What They Assess | Passing Strategy |
|---|---|---|
| Architecture Diagrams | Service selection justification | Start minimal then add redundancy |
| Troubleshooting Flows | Diagnostic methodology | OSI model approach (L1-L7) |
| Cost Estimation | Real-world awareness | Always add 30% buffer for data transfer |
I once had a candidate draw NAT gateways in public subnets. When I asked why, he admitted he confused NAT with internet gateway. Honesty saved him - we hired him after coaching.
Preparation Roadmap That Works
Forget endless documentation reading. After failing my first two AWS cloud interviews, I developed this bootcamp-style approach:
30-Day AWS Interview Prep Plan
- Week 1: Core services deep dive (EC2, S3, VPC, IAM) - build actual projects
- Week 2: Specialized services (Lambda, ECS, DynamoDB, Kinesis) - recreate AWS reference architectures
- Week 3: Troubleshooting drills using AWS Well-Architected Framework
- Week 4: Mock interviews focusing on weak areas
Resource hierarchy matters:
| Resource Type | What to Use | My Rating |
|---|---|---|
| Documentation | AWS FAQs & User Guides | ★★★★★ (essential) |
| Courses | Adrian Cantrill's SA Pro | ★★★★☆ (labs are gold) |
| Practice | CloudFormation templates | ★★★★★ (build everything) |
| Testing | TD practice exams | ★★★☆☆ (outdated sometimes) |
Costly Mistakes in AWS Interview Prep
I'll be brutally honest - people waste months on ineffective prep:
My failed approach: Spent 60 hour watching video tutorials without touching console. Could explain CAP theorem but couldn't provision encrypted RDS instance. Interviewers spot theoretical-only knowledge instantly.
Other common pitfalls:
- Focusing only on associate-level material for professional roles
- Ignoring recent service updates (e.g. not knowing about Aurora Serverless v2)
- Over-preparing for coding when role requires architecture diagrams
Handling Tricky AWS Interview Questions
Interviewers love curveballs. Here's how to handle common AWS interview questions that stump candidates:
Question: "What happens when I press ENTER after SSH command to EC2?"
Basic answer: "Establishes secure connection". Better answer covering:
- TCP 3-way handshake initiation
- Security group rule verification
- Key pair authentication process
- Session encryption negotiation
Question: "How would you move 50TB from on-prem to AWS cheapest?"
Don't default to Snowball. Consider:
- Data deduplication before transfer
- Compression techniques
- Direct Connect vs VPN cost analysis
- Storage class selection (S3 Intelligent-Tiering)
Questions You Should Ask Interviewers
This determines if you should join them. Ask:
| Ask This | Why It Matters |
|---|---|
| "What's your cloud migration regret?" | Reveals operational maturity |
| "How do you handle production incidents?" | Tests process discipline |
| "What IaC tools do you standardize on?" | Shows engineering rigor |
Real Talk About AWS Interview Questions
Having conducted 100+ interviews, I'll share what never gets discussed:
Truth bomb: For senior roles, they care less about CLI commands and more about your disaster recovery strategy when AZs fail. Have you actually tested failover?
Other unspoken realities:
- Contract roles often have harder technical screens than FTEs
- Startups focus more on cost control than enterprises
- Consulting firms care about documentation rigor
My awkward interview: Once blanked on S3 consistency model during high-pressure session. Recovered by sketching eventual consistency flow on whiteboard. Moral: It's okay to get stuck if you show reasoning.
Post-Interview Reality Check
Don't obsess over "how many AWS interview questions I answered correctly". Instead:
| What Matters | Why It Counts |
|---|---|
| Learning trajectory | How quickly you grasped new concepts during interview |
| Problem-solving approach | Did you ask clarifying questions before coding? |
| Culture reflection | Were admins "AWS experts" or "learners"? Run from know-it-alls |
FAQs: AWS Interview Questions Answered
How many rounds for AWS positions?
Varies wildly. Startups: 2-3 rounds. Enterprises: 4-6 including case studies. FAANG: 7+ with system design marathons. Always ask recruiter upfront.
Do they ask leetcode for cloud roles?
Sometimes, but differently. Instead of binary trees, you'll get "optimize S3 file processing pipeline" with real constraints. Practice with AWS-specific scenarios.
What if I fail a certification?
Actually helpful - interviewers respect transparency. Say: "Failed SysOps last month. Discovered I underestimated CloudWatch Logs Insights. Retaking after drilling logs patterns." Shows growth mindset.
Salary negotiation tips?
Research levels.fyi before calls. For cloud roles, specialization matters - Kubernetes on AWS pays 20% more than vanilla EC2 skills. Prove specialized value.
Look, preparing for AWS interview questions isn't about memorizing every service. It's about thinking in cloud patterns. The best question I ever got wasn't technical: "What AWS service would you remove and why?" My answer? "AWS Config - fight me." We spent 20 minutes debating it. Got the offer.