50+ AWS Interview Questions and Answers for 2026

Amazon Web Services remains the dominant force in cloud computing, commanding the largest market share among cloud services providers. For engineers and architects pursuing AWS-focused roles, thorough interview preparation is essential. Companies hiring for cloud positions assess both theoretical knowledge and practical problem-solving ability.

This guide covers AWS interview questions across experience levels and specialized roles, helping you prioritize your preparation efficiently. Whether you're targeting a solutions architect position, a DevOps role, or a data engineering opportunity, understanding these concepts will strengthen your candidacy.

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How to Prepare for an AWS Interview

Before diving into specific questions, understand that AWS interviews vary significantly based on the role. A solutions architect interview focuses on design decisions and high availability patterns, while DevOps positions emphasize automation, CI/CD pipelines, and infrastructure as code. Data engineering roles prioritize services like Redshift, Kinesis, and DynamoDB.

Start by mastering core AWS services that appear in nearly every interview: Amazon EC2, Amazon S3, VPC, IAM, Amazon RDS, and AWS Lambda. Deep understanding of these fundamentals demonstrates solid knowledge and provides context for learning specialized services.

Modern interviews go beyond memorization. Interviewers want to see how you approach real-world challenges, make architectural decisions, and debug issues. Practice designing solutions and explaining your reasoning. If you're also preparing for broader IT interview questions, many foundational concepts overlap.

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Foundational AWS Interview Questions

What is AWS, and why do companies choose it?

AWS is Amazon's comprehensive cloud platform offering 200+ services spanning compute, storage, databases, networking, analytics, and machine learning. Companies choose AWS for its first-mover advantage, global infrastructure spanning multiple AWS regions, breadth of services, and continuous innovation. The on-demand pricing model allows organizations to provision resources without upfront capital expenditure, paying only for what they use.

Explain the difference between AWS Regions and Availability Zones

Regions are geographically separate locations (like us-east-1 or eu-west-2), while availability zones are isolated data centers within a region. Each AWS region has multiple availability zones connected by low latency links. This architecture enables fault tolerance and disaster recovery. When designing for high availability, you deploy resources across multiple availability zones so that if one data center fails, your workload continues running.

What is the AWS Shared Responsibility Model?

This fundamental security concept divides responsibilities between AWS and customers. AWS manages security "of" the cloud, including physical infrastructure, networking hardware, and the hypervisor. Customers handle security "in" the cloud: data encryption, application security, identity and access management, operating system patching, and firewall configuration through security groups. Understanding these permissions boundaries is critical for any AWS role.

What is Amazon EC2?

Amazon EC2 (Elastic Compute Cloud) provides virtual servers with configurable compute capacity. When selecting instance types, consider CPU requirements, memory needs, network throughput, and pricing. Instance families include general purpose, compute optimized, memory optimized, and storage optimized. For cost optimization, evaluate reserved instances for predictable workloads or spot instances for fault-tolerant applications.

What is the difference between stopping and terminating an EC2 instance?

Stopping an instance preserves the root EBS volume and instance metadata while halting compute charges. The instance can restart later. Terminating permanently deletes the instance and, by default, its root volume. Stopped EC2 instances still incur EBS storage costs. Enable termination protection for critical instances to prevent accidental deletion.

What is Amazon S3?

Amazon S3 (Simple Storage Service) is object storage with virtually unlimited scalability. S3 guarantees 99.999999999% (11 nines) durability through automatic replication across multiple availability zones. Use cases include static website hosting, backups, data lakes, and application assets. Understanding S3 bucket security, lifecycle policies, and storage classes like S3 Glacier for archival is essential.

What is Amazon VPC?

A Virtual Private Cloud is a logically isolated network within AWS where you launch resources. Core components include subnets (public and private subnet configurations), route tables for routing decisions, internet gateways, NAT gateway for outbound traffic from private subnets, security groups acting as instance-level firewalls, and network ACLs for subnet-level control.

What is IAM?

Identity and Access Management controls access to AWS resources. IAM includes users, groups, IAM roles, and policies defining permissions. Roles provide temporary credentials for services and cross-account access, preferred over long-term user credentials. The principle of least privilege guides IAM design: grant only the permissions necessary for specific tasks.

Compare Security Groups and Network ACLs

Security groups are stateful, operate at the instance level, allow rules only, and evaluate all rules before deciding. Network ACLs are stateless, operate at the subnet level, support allow and deny rules, and process rules in order. Use both for defense in depth. Security groups handle most use cases, while network ACLs provide additional subnet-level control.

What is Amazon CloudWatch?

CloudWatch is AWS's monitoring and observability service. It collects metrics from AWS resources, aggregates logs, triggers alarms based on thresholds, and displays dashboards. CloudWatch integrates with auto scaling to automatically adjust capacity based on metrics and supports real-time monitoring of your applications.

What is AWS Lambda?

AWS Lambda is a serverless computer that runs code in response to events without managing servers. Lambda offers automatic scalability, pay-per-execution pricing, and zero infrastructure management. Unlike EC2 instances, Lambda has execution time limits and cold start considerations. It excels for event-driven workloads, API backends, and data processing pipelines.

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Intermediate AWS Interview Questions

What are the different S3 storage classes?

S3 offers multiple storage classes with different cost and access trade-offs. S3 Standard suits frequently accessed data. S3 Intelligent-Tiering automatically moves objects between tiers. S3 Standard-IA and One Zone-IA serve infrequently accessed data. S3 Glacier options (Instant Retrieval, Flexible Retrieval, Deep Archive) provide archival storage with varying retrieval times. Lifecycle policies automate transitions between classes.

Compare Amazon RDS with DynamoDB

Amazon RDS provides managed relational database engines including MySQL, PostgreSQL, and others, supporting complex SQL queries and ACID transactions. DynamoDB is a NoSQL database offering single-digit millisecond latency, flexible schema, and automatic scaling. Choose RDS for structured data with complex relationships. Choose DynamoDB for high-throughput key-value access patterns and horizontal scalability.

If you're preparing for database-focused roles, reviewing SQL interview questions strengthens your relational database knowledge.

Explain Elastic Load Balancer types

AWS offers multiple ELB options. Application Load Balancer operates at Layer 7, handling HTTP/HTTPS with path-based routing for web applications. Network Load Balancer operates at Layer 4, providing ultra-low latency and static IP addresses. Gateway Load Balancer integrates third-party appliances. Classic Load Balancer is legacy. Selection depends on your application's protocol and performance requirements.

What is an Auto Scaling Group?

Auto scaling groups manage collections of EC2 instances for automatic scaling based on demand. Required components include launch templates defining instance configuration, minimum/maximum/desired capacity settings, scaling policies (target tracking, step, simple), and health checks. ASGs integrate with elastic load balancers to distribute traffic across healthy instances, ensuring high availability.

What is AWS CloudFormation?

AWS CloudFormation is infrastructure as code (IaC) using JSON or YAML templates to provision AWS resources. It enables version control, repeatability, and automated provisioning. Key concepts include stacks (collections of resources), change sets (preview changes), and drift detection. CloudFormation supports nested templates for modular architectures. Terraform offers a similar IaC approach with multi-cloud support.

How do you secure an S3 bucket?

Implement multiple security layers: bucket policies and ACLs for access control, block public access settings, encryption at rest (SSE-S3, SSE-KMS using AWS Key Management Service, or SSE-C), versioning for data protection, MFA delete for critical buckets, access logging for audit trails, and VPC endpoints for private access. Defense in depth prevents single points of failure.

Compare S3, EBS, and EFS

S3 is object storage accessed via API with unlimited capacity. EBS provides block storage attached to single EC2 instances with high performance for databases. EFS offers shared file system storage accessible from multiple instances. Choose S3 for static assets and data lakes, EBS for boot volumes and databases requiring low latency, EFS for shared application data.

What is the difference between RDS Read Replicas and Multi-AZ?

Read Replicas provide read scalability using asynchronous replication, can exist in different regions, and serve read traffic. Multi-AZ provides high availability with synchronous replication and automatic failover to a standby instance. Read Replicas scale read performance; Multi-AZ ensures durability and availability. Many production deployments use both.

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Advanced AWS Interview Questions

Design a highly available web application architecture

A robust architecture includes: multi-AZ deployment across availability zones, auto scaling groups for compute, application load balancer distributing traffic, Amazon RDS Multi-AZ for the database, Amazon S3 for static assets, CloudFront CDN for global content delivery, and Route 53 for DNS with health checks and failover routing. This design addresses fault tolerance, scalability, and disaster recovery requirements.

Compare VPC Peering with AWS Transit Gateway

VPC Peering creates point-to-point connections between VPCs but is non-transitive and doesn't scale well with many VPCs. Transit Gateway provides a hub-and-spoke model with transitive routing, centralized management, and support for thousands of VPCs. Transit Gateway costs more but simplifies complex networking. Choose peering for simple two-VPC scenarios; choose Transit Gateway for enterprise multi-VPC architectures.

What is a Lambda cold start and how do you mitigate it?

Cold starts occur when Lambda creates new execution environments, adding latency to the first request. Mitigation strategies include provisioned concurrency (keeps environments warm), optimizing deployment package size, choosing appropriate runtimes, minimizing initialization code, and keeping functions warm with scheduled invocations. Understanding cold starts matters for latency-sensitive workloads.

Design a CI/CD pipeline for containerized applications

Use CodePipeline for orchestration, connecting to GitHub or CodeCommit for source control. CodeBuild handles building and testing, pushing images to ECR (Elastic Container Registry). Deploy to ECS or EKS (Kubernetes) using CodeDeploy or native deployment controllers. Implement blue-green deployments for zero-downtime releases with rollback capability. This workflow enables continuous automation from commit to production.

For comprehensive preparation on DevOps engineer interview questions, focus on CI/CD, Docker, and automation patterns.

Explain the AWS Well-Architected Framework

The framework includes six pillars: Operational Excellence (automation, monitoring), Security (identity and access management, data protection), Reliability (fault tolerance, disaster recovery), Performance Efficiency (right-sizing, caching), Cost Optimization (reserved instances, cost explorer analysis), and Sustainability (environmental impact). These pillars guide architectural decisions and provide evaluation criteria for workloads.

How would you optimize AWS costs?

Cost optimization strategies include: right-sizing instances based on actual CPU and memory utilization, using reserved instances or Savings Plans for predictable workloads, leveraging spot instances for fault-tolerant processing, implementing S3 lifecycle policies to move data to cheaper tiers, reviewing unused resources with Cost Explorer and Trusted Advisor, and choosing appropriate storage classes. Cost-effective architecture balances performance with spending.

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Scenario-Based Questions

Your web application experiences intermittent 502 errors during peak traffic. How do you troubleshoot?

Systematically investigate: check ALB access logs for error patterns, verify target health checks and configuration, examine application logs for exceptions, review timeout settings, confirm security groups allow necessary traffic, and assess whether targets are overwhelmed. Metrics from CloudWatch help identify whether the issue is capacity, configuration, or application-level. Methodical debugging prevents guesswork.

IAM access keys were accidentally committed to GitHub. What's your incident response?

Immediately rotate and delete the compromised credentials. Review CloudTrail logs for unauthorized access during the exposure window. Assess what AWS resources those credentials could access. Implement preventive measures including git-secrets scanning, credential rotation policies, and developer training. Document the incident and update security procedures.

Understanding how companies evaluate candidates through their tech interview process helps you prepare for these scenario-based discussions.

Design a real-time IoT data processing system

Use IoT Core for device connectivity, Kinesis Data Streams for high-throughput ingestion, Lambda or Kinesis Data Analytics for processing, DynamoDB for hot data with low latency access, S3 for raw data archival, and QuickSight for dashboards. Consider partition strategies for scalability and throughput requirements. This architecture handles messaging from thousands of devices with real-time analytics.

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Data Engineering Questions

How would you set up a data lake on AWS?

S3 serves as the storage layer with appropriate bucket organization. AWS Glue handles ETL and maintains the data catalog. Lake Formation provides governance and fine-grained permissions. Athena enables serverless SQL queries directly on S3. Redshift Spectrum integrates data warehouse queries with the lake. Choose columnar formats like Parquet for analytical workloads and implement partitioning for query performance.

If you're deciding between roles, understanding the difference between a data engineer vs data scientist clarifies which AWS services matter most for your career path.

Preparing for Success

AWS interviews test depth of knowledge and practical thinking. Preparation should include hands-on practice with AWS Free Tier, not just memorization. Success comes from demonstrating how you approach problems, make trade-offs, and learn continuously.

Understanding how leading companies build the ultimate interview process gives you insight into what evaluators prioritize.

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Frequently Asked Questions (FAQs)

Do I need AWS certification? 

Certifications validate knowledge and help pass resume screening but aren't strictly required. Hands-on experience matters more for senior roles. Consider certifications as complements to practical skills.

Which services should I prioritize? 

Focus on EC2, S3, VPC, IAM, RDS, Lambda, and CloudFormation as foundations. Then specialize based on your target role.

How important is hands-on experience? 

Critical, especially for senior positions. Interviewers distinguish between candidates who've read documentation versus those who've deployed and debugged real systems.

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Ready to Land Your Next AWS Role?

Mastering AWS interview questions is one piece of landing your ideal role. Finding companies that match your skills, seniority, and career goals requires equal attention.

Lupa connects senior LATAM professionals with leading U.S. and global companies seeking genuine AWS expertise. Our methodology-driven approach includes deep technical evaluation, cultural fit assessment, and comprehensive preparation support. We work with companies actively hiring across solutions architect, DevOps, and data engineering roles.

Great AWS knowledge opens doors. Strategic representation ensures you walk through the right ones.

Book a discovery call to explore opportunities that match your cloud expertise.

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