AWS Developer Associate DVA-C02 Study Guide 2026

The AWS Certified Developer - Associate (DVA-C02) is the certification for engineers who build and deploy applications on AWS every day. Unlike the Solutions Architect Associate, which focuses on designing architectures from scratch, the Developer Associate is centered on the development workflow — how you write, debug, deploy, and monitor code running on AWS services. If you already know how to code and want to prove you can do it natively in the AWS ecosystem, this guide gives you the service-by-service knowledge you need.

Lambda Function Best Practices

AWS Lambda is the heart of the DVA-C02 exam. Expect questions on cold start behavior, execution context reuse, and deployment package limits. The exam tests your ability to apply best practices, not just define terms.

• Execution context reuse: Initialize SDK clients, database connections, and configuration outside the handler function so they persist across warm invocations. The exam frequently tests whether candidates understand what lives inside vs. outside the handler.
• Environment variables: Store configuration values and use AWS Secrets Manager or Parameter Store for sensitive data. Know the difference between encrypting environment variables with a customer-managed KMS key vs. the default Lambda-managed key.
• Concurrency: Understand reserved concurrency (caps a function's maximum) vs. provisioned concurrency (eliminates cold starts for latency-sensitive workloads). Know how account-level concurrency limits interact with per-function limits.
• Layers: Use Lambda Layers to share common dependencies across functions. The exam tests the maximum number of layers per function (5) and the total unzipped size limit.
• Aliases and versions: Understand how to use Lambda aliases with weighted traffic shifting to implement canary deployments — a common exam scenario.

API Gateway and Lambda Integration Patterns

API Gateway + Lambda is the most tested integration on the DVA-C02 exam. Know the difference between REST APIs and HTTP APIs in API Gateway: HTTP APIs are cheaper and lower-latency but lack features like request validation, usage plans, and WAF integration. REST APIs are the exam default unless cost optimization is the stated goal.

For Lambda proxy integration, the event object contains the full HTTP request (headers, path parameters, query string, body). The function must return a structured response with statusCode, headers, and body. Non-proxy (custom) integration lets you transform the request and response using Velocity Template Language (VTL) mapping templates — know the basic syntax for extracting parameters and constructing a JSON payload.

Stage variables act like environment variables for API Gateway deployments. They let you route traffic to different Lambda aliases per stage (dev, staging, prod). Exam questions often ask how to promote a deployment or blue/green switch without changing the API consumer's endpoint.

DynamoDB Data Modeling for Developers

DynamoDB appears heavily on the DVA-C02 and trips up many candidates who are used to relational databases. The key mental model shift: you design your table around access patterns, not normalized entities.

• Partition key and sort key: The partition key determines the physical partition. Adding a sort key creates a composite primary key and enables range queries within a partition. Always choose partition keys with high cardinality to distribute load evenly.
• Global Secondary Indexes (GSI) vs. Local Secondary Indexes (LSI): GSIs can have any partition key and are eventually consistent. LSIs share the base table's partition key, support strong consistency, but must be created at table-creation time and cannot be deleted.
• Read/Write capacity modes: On-demand mode auto-scales with no capacity planning; provisioned mode requires setting RCUs and WCUs and is more cost-effective for predictable workloads. Know how DynamoDB Auto Scaling works with provisioned mode.
• Transactions: TransactWriteItems and TransactGetItems allow atomic operations across up to 25 items (or 4 MB). Know the use case — financial transfers, inventory updates — and that transactions consume 2x the capacity units.
• DynamoDB Streams: Enable change data capture. Events flow to Lambda for event-driven processing. Know the four StreamViewType options: KEYS_ONLY, NEW_IMAGE, OLD_IMAGE, NEW_AND_OLD_IMAGES.

Event-Driven Patterns: SQS, SNS, and EventBridge

The DVA-C02 heavily tests event-driven architecture. The three core services — SQS, SNS, and EventBridge — are often tested together in scenario questions asking you to pick the right integration.

SQS is for decoupling producers from consumers with durable queuing. Know the difference between Standard queues (at-least-once delivery, best-effort ordering) and FIFO queues (exactly-once processing, strict ordering, lower throughput). Visibility timeout determines how long a message is hidden after a consumer reads it — set it longer than your Lambda timeout to avoid duplicate processing. Dead-letter queues (DLQs) capture messages that fail processing after the maxReceiveCount threshold.

SNS is for fan-out — one message, multiple subscribers. Combined with SQS, the SNS-to-SQS fan-out pattern lets you broadcast a single event to multiple processing pipelines. EventBridge is the evolution of CloudWatch Events and is the right answer for complex event routing, third-party SaaS integrations, and schema-driven event buses. Know EventBridge rules, event patterns, and targets.

X-Ray Tracing and Debugging

AWS X-Ray provides distributed tracing across Lambda, API Gateway, and other services. For the exam, know how to enable active tracing on Lambda (AWS_XRAY_TRACING enabled in the function configuration) and how the X-Ray SDK creates subsegments to capture downstream calls to DynamoDB, S3, or HTTP endpoints.

The service map in X-Ray console visualizes latency and error rates between components — a common question context. Annotations are indexed metadata that can be used to filter traces in the X-Ray console. Metadata is non-indexed and can store richer data. Know the difference for the exam.

CI/CD with CodePipeline, CodeBuild, and CodeDeploy

AWS developer tooling is a reliable exam domain. CodePipeline orchestrates the pipeline stages. CodeBuild compiles code and runs tests using a buildspec.yml file — know the phases (install, pre_build, build, post_build) and how to publish artifacts. CodeDeploy automates deployments to EC2, on-premises servers, Lambda, and ECS.

• Deployment strategies for Lambda: Canary (e.g., CodeDeployDefault.LambdaCanary10Percent5Minutes shifts 10% traffic, then 100% after 5 minutes), Linear, and All-at-once. Each strategy can trigger CloudWatch alarms to initiate automatic rollback.
• AppSpec file: CodeDeploy uses an appspec.yml that defines hooks for BeforeAllowTraffic and AfterAllowTraffic Lambda functions to run validation tests during a deployment.
• CodeArtifact: A managed artifact repository for npm, Maven, and pip packages. Know how to configure package managers to authenticate against CodeArtifact using temporary tokens fetched via the CLI.

Certify Copilot's DVA-C02 practice questions simulate the scenario-based format of the real exam, reinforcing service behavior, limits, and architectural trade-offs across all these domains so you can build both confidence and speed before exam day.