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Brent G Saucedo
Brent G Saucedo

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AZ-204 Azure Developer Associate Cheat Sheet – 2026 Exam Notes

#azure #cloud #certification #devops

The Microsoft Azure Developer Associate (AZ-204) is the essential certification for cloud developers. While the AZ-104 is about managing infrastructure, the AZ-204 is about coding against it.

If you're preparing for the 2026 exam, this deep-dive covers the critical SDK patterns, consistency models, and configuration "gotchas."

1. Develop Azure Compute Solutions (25-30%)

As a developer, you need to know how to host code without managing the underlying VM.

App Service (PaaS)

  • Deployment Slots: (Standard tier+) Used for zero-downtime deployments.
    • Sticky Settings: Mark as "Deployment slot setting" to prevent a setting (like a Dev DB string) from moving to Prod during a swap.
  • CORS: Must be configured in the App Service portal to allow cross-origin JavaScript calls from your frontend.

Azure Functions (Serverless)

  • Consumption Plan: Automatic scaling, pay-per-execution. 1.5GB RAM limit.
  • Premium Plan: Eliminates cold starts, VNET integration, longer timeouts.
  • Durable Functions: State management for serverless.
    • Orchestrator: Defines the workflow. Must be deterministic (No DateTime.Now or Guid.NewGuid).
    • Activity: The function that performs the actual task.

2. Develop for Azure Storage (15-20%)

Focus on how to interact with data via SDKs.

Azure Cosmos DB (SQL API)

  • Consistency Levels: (The "Must-Know" for the exam)
    1. Strong: Highest consistency, highest latency.
    2. Bounded Staleness: Reads lag behind writes by a defined interval.
    3. Session: (Default) Consistent prefix within a single user session.
    4. Consistent Prefix: Updates appear in the correct order.
    5. Eventual: Fastest performance; no guarantee of order.
  • Partition Key: Choose a property with high cardinality to avoid "Hot Partitions."

Blob Storage SDK

  • Access Tiers: Hot (Frequent), Cool (>30 days), Archive (>180 days, requires rehydration).
  • Lifecycle Management: Automate moves between tiers using JSON policies.
  • SAS Tokens: Use User Delegation SAS for best security (backed by Entra ID).

3. Implement Azure Security (15-20%)

The exam heavily tests Zero Trust and secret-less communication.

  • Managed Identities:
    • System-Assigned: Tied to the lifecycle of the resource.
    • User-Assigned: Standalone resource; can be shared across multiple resources.
  • Azure Key Vault: Store Secrets (strings), Keys (encryption), and Certificates. Use RBAC for modern access control.
  • Microsoft Graph: The API for interacting with Entra ID (Users, Groups). Requires GraphServiceClient.

4. Connect to & Consume Azure Services (20-25%)

How to make microservices talk to each other.

Service Type Use Case
Service Bus Message High reliability, transactions, FIFO.
Event Grid Event Reactive programming (e.g., "File uploaded -> Run Function").
Event Hubs Event Big data streaming, telemetry (millions of events/sec).
Queue Storage Message Simple, massive scale, local to a storage account.

API Management (APIM)

  • Policies: XML snippets to change API behavior.
    • <inbound>: Rate limits, JWT validation.
    • <outbound>: Format conversion (XML to JSON).

5. Monitor, Troubleshoot, & Optimize (5-10%)

  • Application Insights: Use the SDK to track custom events, exceptions, and dependencies.
  • Log Analytics: Search logs using KQL (Kusto Query Language).
  • Availability Tests: Use "Ping" tests to ensure your endpoint is reachable globally.

Developer "Gotchas"

  • Tags don't inherit: Tagging a Resource Group does NOT tag the resources inside.
  • App Configuration: Used for centralized Feature Flags.
  • Redis Cache: Implement the Cache-Aside Pattern.
  • Instrumentation Key: Required to link your code to Application Insights.

Good luck with your AZ-204!

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