question: 1
A developer is building a serverless application that must respond to image uploads in Amazon S3. Which service should be used to handle this event?
A. Amazon EC2
B. Amazon SQS
C. AWS Lambda
D. Amazon DynamoDB
correct answer: C
explanation: ⚡ AWS Lambda can be triggered by S3 events to process new object uploads in real time.

question: 2
Which AWS service provides temporary security credentials for users or applications?
A. IAM
B. Amazon Cognito
C. AWS STS
D. AWS KMS
correct answer: C
explanation: 🕒 AWS Security Token Service (STS) provides temporary, limited-privilege credentials for IAM roles or federated users.

question: 3
A developer wants to use environment variables in a Lambda function. Where should they be set?
A. In the code
B. In Lambda function configuration
C. In an S3 bucket
D. In IAM policy
correct answer: B
explanation: ⚙️ Environment variables for Lambda functions can be defined in the configuration for easier code reuse and management.

question: 4
Which service allows you to deploy a Docker container without managing servers?
A. Amazon EC2
B. AWS Lambda
C. Amazon ECS Fargate
D. AWS CodeBuild
correct answer: C
explanation: 🐳 ECS Fargate lets you run containers without managing EC2 instances, offering a fully serverless experience.

question: 5
How can a developer track usage of an API deployed in Amazon API Gateway?
A. AWS Config
B. CloudTrail
C. Amazon CloudWatch Metrics
D. AWS X-Ray
correct answer: C
explanation: 📊 CloudWatch Metrics tracks API Gateway performance such as request count and latency.

question: 6
What does Amazon DynamoDB use as its primary data structure?
A. Tables
B. Buckets
C. Streams
D. Queues
correct answer: A
explanation: 📁 DynamoDB stores data in tables composed of items and attributes.

question: 7
Which AWS service simplifies user sign-up and authentication for web and mobile apps?
A. IAM
B. Cognito
C. KMS
D. STS
correct answer: B
explanation: 🔐 Amazon Cognito handles user authentication and federation with built-in support for social identity providers.

question: 8
A Lambda function needs access to an S3 bucket. What is the best practice to allow this?
A. Embed credentials in the function
B. Use hard-coded access keys
C. Attach an IAM role to the Lambda function
D. Create a public S3 bucket
correct answer: C
explanation: 🛡️ The best practice is to use IAM roles attached to Lambda functions for secure access.

question: 9
Which service allows a developer to automate builds and run unit tests?
A. CodeCommit
B. CodePipeline
C. CodeDeploy
D. CodeBuild
correct answer: D
explanation: 🧪 CodeBuild compiles source code, runs tests, and produces artifacts for deployment.

question: 10
What feature of DynamoDB helps reduce read latency by keeping data close to users?
A. Global tables
B. Streams
C. TTL
D. Secondary indexes
correct answer: A
explanation: 🌍 Global tables replicate data across AWS Regions, ensuring low-latency reads worldwide.

question: 11
Which of the following can be used to trace a request through multiple services in a microservice app?
A. CloudWatch
B. X-Ray
C. S3
D. SNS
correct answer: B
explanation: 🧵 AWS X-Ray helps developers analyze and debug distributed applications using request tracing.

question: 12
Which database is best suited for storing key-value data at high speed and low latency?
A. RDS
B. Redshift
C. DynamoDB
D. Neptune
correct answer: C
explanation: 🚀 DynamoDB is optimized for key-value and document data access with single-digit millisecond latency.

question: 13
A developer is using Amazon SQS. What feature ensures that each message is only processed once?
A. FIFO queues
B. Dead-letter queues
C. Visibility timeout
D. Batch processing
correct answer: A
explanation: 🔁 FIFO queues ensure exactly-once processing with preserved message order.

question: 14
What allows a Lambda function to scale automatically with increasing requests?
A. VPC
B. S3
C. Built-in concurrency
D. IAM role
correct answer: C
explanation: 🚦 Lambda handles automatic scaling using built-in concurrency control.

question: 15
Which AWS tool helps detect and troubleshoot errors in Lambda functions?
A. CloudWatch Logs
B. IAM
C. CodeDeploy
D. AWS Config
correct answer: A
explanation: 📋 CloudWatch Logs captures logs from Lambda executions for analysis and debugging.

question: 16
Which of the following services can invoke a Lambda function directly?
A. S3
B. CloudFront
C. IAM
D. CloudFormation
correct answer: A
explanation: 🗂️ S3 can invoke a Lambda function when events such as object creation occur.

question: 17
Where should a developer store database credentials securely?
A. Environment variable
B. Code comments
C. AWS Secrets Manager
D. Plain text in S3
correct answer: C
explanation: 🔐 AWS Secrets Manager stores, rotates, and retrieves secrets securely.

question: 18
What service lets developers create RESTful APIs with integrated Lambda functions?
A. CloudFormation
B. AppSync
C. API Gateway
D. S3
correct answer: C
explanation: 🌐 API Gateway is commonly used to create REST APIs that trigger Lambda functions.

question: 19
Which of the following AWS services supports WebSocket communication?
A. SNS
B. API Gateway
C. DynamoDB
D. CloudTrail
correct answer: B
explanation: 📡 API Gateway supports WebSocket APIs for real-time, bidirectional communication.

question: 20
Which tool is used to define and provision AWS infrastructure using code?
A. CloudWatch
B. X-Ray
C. CloudFormation
D. IAM
correct answer: C
explanation: 🏗️ AWS CloudFormation lets you define your infrastructure as code using templates.

question: 21
A developer needs to test Lambda locally. Which AWS tool can help?
A. AWS SDK
B. AWS CLI
C. AWS SAM
D. CloudTrail
correct answer: C
explanation: 🧪 AWS SAM (Serverless Application Model) enables local development and testing of Lambda functions.

question: 22
How do you grant temporary access to an S3 bucket from a mobile app?
A. Create public access
B. Use AWS Secrets Manager
C. Use pre-signed URLs
D. Use static credentials
correct answer: C
explanation: 🔑 Pre-signed URLs allow temporary, secure access to S3 objects without sharing credentials.

question: 23
Which AWS service can automate deployments across multiple environments (dev, test, prod)?
A. CodeBuild
B. CodeDeploy
C. CodePipeline
D. Elastic Beanstalk
correct answer: C
explanation: 🔁 CodePipeline automates the build-test-deploy workflow across multiple stages.

question: 24
Which database is best for querying relationships between entities?
A. DynamoDB
B. Aurora
C. Neptune
D. Redshift
correct answer: C
explanation: 🔗 Amazon Neptune is optimized for graph queries and relationships between entities.

question: 25
What feature helps a developer version Lambda functions?
A. Tags
B. Layers
C. Aliases
D. Snapshots
correct answer: C
explanation: 🔁 Aliases point to specific Lambda function versions, making deployment and rollback easier.

question: 26
What is the best way to manage app config separately from code in Lambda?
A. Environment variables
B. S3 bucket names in code
C. Hard-coded values
D. Code comments
correct answer: A
explanation: ⚙️ Environment variables separate configuration from code and support flexible deployments.

question: 27
Which storage class is best for infrequently accessed S3 data?
A. S3 Standard
B. S3 Intelligent-Tiering
C. S3 Glacier
D. S3 One Zone-IA
correct answer: C
explanation: ❄️ S3 Glacier is cost-effective for long-term storage of data that’s rarely accessed.

question: 28
Which tool enables source control for AWS developers?
A. CodeDeploy
B. CodePipeline
C. CodeCommit
D. CodeBuild
correct answer: C
explanation: 🗃️ CodeCommit is a secure, scalable, Git-based repository hosted by AWS.

question: 29
What service helps developers debug performance bottlenecks across AWS resources?
A. CloudTrail
B. CodePipeline
C. X-Ray
D. S3
correct answer: C
explanation: 🕵️‍♂️ AWS X-Ray traces requests across services and helps pinpoint performance issues.

question: 30
How does DynamoDB automatically handle increasing read/write loads?
A. Horizontal scaling
B. Manual provisioning
C. Global replication
D. Fixed throughput
correct answer: A
explanation: 📈 DynamoDB uses horizontal scaling and auto-scaling to handle increased workloads seamlessly.

question: 31
What service lets you send mobile push notifications to iOS and Android devices?
A. Amazon SNS
B. Amazon SQS
C. AWS Lambda
D. Amazon MQ
correct answer: A
explanation: 📱 Amazon SNS supports mobile push notifications to platforms like iOS, Android, and more.

question: 32
How can a developer limit access to an S3 bucket for only specific IP addresses?
A. IAM Role
B. S3 Bucket Policy
C. Lambda authorizer
D. Signed URLs
correct answer: B
explanation: 🔐 Bucket policies can include IP-based conditions to restrict access.

question: 33
Which AWS service helps protect applications against common web exploits?
A. AWS Shield
B. AWS WAF
C. Amazon Inspector
D. Amazon Macie
correct answer: B
explanation: 🛡️ AWS WAF is a web application firewall that protects against threats like SQL injection and XSS.

question: 34
How can a developer avoid race conditions when updating items in DynamoDB?
A. Use scan operations
B. Use conditional writes
C. Use eventual consistency
D. Use parallel writes
correct answer: B
explanation: ⚖️ Conditional writes help ensure updates only occur when the expected state exists.

question: 35
Which AWS service can transform and enrich streaming data in near real-time?
A. Kinesis Firehose
B. AWS Glue
C. Kinesis Data Analytics
D. Lambda
correct answer: C
explanation: 🔁 Kinesis Data Analytics enables SQL-based stream processing in real time.

question: 36
A developer wants to retry failed API calls with exponential backoff. Which AWS SDK feature supports this?
A. Event bridge
B. Retry handler
C. Waiter utility
D. Circuit breaker
correct answer: B
explanation: ♻️ Most AWS SDKs have built-in retry handlers that use exponential backoff for resilience.

question: 37
Which service would a developer use to monitor custom metrics?
A. CloudTrail
B. CloudWatch
C. X-Ray
D. Config
correct answer: B
explanation: 📊 CloudWatch supports both default and custom metrics for application monitoring.

question: 38
Which AWS service allows you to run GraphQL APIs?
A. API Gateway
B. AppSync
C. Lambda
D. CloudFront
correct answer: B
explanation: 🧬 AWS AppSync is designed for building GraphQL APIs with real-time and offline support.

question: 39
What type of IAM policy allows access only during working hours?
A. Inline policy
B. Session policy
C. Time-based condition policy
D. Managed policy
correct answer: C
explanation: 🕒 Time-based conditions in IAM policies restrict actions based on date/time.

question: 40
Which service enables blue/green deployments for Lambda?
A. CodePipeline
B. CodeCommit
C. CodeDeploy
D. CodeBuild
correct answer: C
explanation: 🔄 CodeDeploy supports traffic shifting and blue/green deployments for Lambda functions.

question: 41
A developer needs to store structured, relational data. Which service is best?
A. DynamoDB
B. S3
C. RDS
D. CloudFront
correct answer: C
explanation: 🗃️ Amazon RDS provides a fully managed relational database solution.

question: 42
Which tool allows developers to simulate AWS services locally?
A. CloudFormation
B. LocalStack
C. SAM CLI
D. Elastic Beanstalk
correct answer: B
explanation: 💻 LocalStack emulates AWS services locally for development and testing.

question: 43
How do you prevent a user from deleting S3 objects but still allow uploading?
A. Use S3 versioning
B. Use bucket ACLs
C. Use IAM deny policy for s3:DeleteObject
D. Enable MFA delete
correct answer: C
explanation: 🚫 IAM policies can explicitly deny delete actions while allowing uploads.

question: 44
Which service supports infrastructure version control?
A. CloudWatch
B. X-Ray
C. CloudFormation
D. CodeDeploy
correct answer: C
explanation: 🔁 AWS CloudFormation templates can be versioned and tracked in code repositories.

question: 45
What Lambda feature improves deployment efficiency and reusability?
A. Layers
B. Aliases
C. Tags
D. Environment Variables
correct answer: A
explanation: 📦 Lambda Layers let you package libraries and dependencies separately from function code.

question: 46
Which service is best suited for streaming large volumes of real-time data?
A. SNS
B. SQS
C. Kinesis Data Streams
D. CloudTrail
correct answer: C
explanation: 🔥 Kinesis Data Streams is built for high-throughput, low-latency streaming ingestion.

question: 47
How can a developer protect source code stored in AWS CodeCommit?
A. Enable encryption at rest
B. Use Cognito
C. Use KMS manually
D. Enable Lambda triggers
correct answer: A
explanation: 🔐 CodeCommit encrypts data at rest using AWS-managed KMS by default.

question: 48
What ensures Lambda’s retry mechanism for asynchronous invocations?
A. Dead-letter queues
B. Step Functions
C. Batch processing
D. Timeout setting
correct answer: A
explanation: 📩 DLQs capture failed invocations for later analysis and retries.

question: 49
Which AWS service helps find exposed secrets in source code?
A. Macie
B. CodeGuru
C. Inspector
D. Secrets Detector (via Amazon CodeWhisperer)
correct answer: D
explanation: 🔍 CodeWhisperer and Secrets Detector flag hard-coded secrets in developer code.

question: 50
Which HTTP method is used in a REST API to update an existing resource?
A. GET
B. PUT
C. POST
D. DELETE
correct answer: B
explanation: 🔧 PUT replaces a resource or creates it if it doesn’t exist in RESTful design.

question: 51
Which AWS service offers fully managed Git repositories?
A. CodePipeline
B. CodeDeploy
C. CodeCommit
D. CodeBuild
correct answer: C
explanation: 🧾 CodeCommit is AWS’s Git-based code repository service.

question: 52
What AWS service can help automatically identify inefficient code?
A. CloudTrail
B. CodeDeploy
C. CodeGuru Profiler
D. X-Ray
correct answer: C
explanation: 🧠 CodeGuru Profiler analyzes runtime performance and identifies code bottlenecks.

question: 53
Which service supports real-time application metrics and dashboards?
A. CloudTrail
B. CloudFormation
C. CloudWatch
D. Config
correct answer: C
explanation: 📈 CloudWatch provides dashboards for real-time application metrics and alarms.

question: 54
A developer wants to schedule a daily task to run a Lambda. What should be used?
A. API Gateway
B. CloudTrail
C. EventBridge (or CloudWatch Events)
D. CodePipeline
correct answer: C
explanation: ⏰ EventBridge allows cron-like scheduling for Lambda invocations.

question: 55
Which AWS feature protects an API against excessive requests?
A. Lambda concurrency
B. API Gateway throttling
C. IAM rate limiting
D. X-Ray
correct answer: B
explanation: 🚦 API Gateway has built-in throttling to prevent abuse and overuse.

question: 56
Which method enables secure, serverless file uploads to S3 from a frontend?
A. Public bucket
B. Lambda function
C. Pre-signed URLs
D. S3 direct URL
correct answer: C
explanation: 🔐 Pre-signed URLs give secure, time-limited access for uploading directly to S3.

question: 57
How can a developer reduce cold start times for a Lambda function?
A. Increase memory
B. Use provisioned concurrency
C. Use Python runtime
D. Disable VPC
correct answer: B
explanation: 🚀 Provisioned concurrency keeps functions pre-warmed and reduces cold start latency.

question: 58
Which is the best method for managing large environment configurations in Lambda?
A. Hard-code in function
B. Use S3
C. Use AWS Systems Manager Parameter Store
D. Use CloudTrail
correct answer: C
explanation: 🧾 Parameter Store securely stores configuration values and secrets for apps.

question: 59
Which AWS service helps with decoupling microservices using a publish-subscribe model?
A. Lambda
B. DynamoDB
C. SQS
D. SNS
correct answer: D
explanation: 📣 SNS enables loosely coupled microservices through pub-sub communication.

question: 60
What AWS feature allows developers to simulate REST API errors and test retries?
A. Lambda test events
B. API Gateway mock integration
C. CloudWatch Insights
D. S3 event notifications
correct answer: B
explanation: 🎭 API Gateway mock integrations let developers simulate responses and errors for testing.