AZ-204 Study Guide — Developing Solutions for Microsoft Azure

AZ-204: Developing Solutions for Microsoft Azure

Key Takeaways

• Highest-weight domain (25–30%): Azure Compute — know App Service and Azure Functions cold
• Identity (Entra ID, managed identities) appears across multiple domains — don’t skip it
• The exam tests SDK usage, not just concepts — write real code with Azure.Storage.Blobs, Azure.Security.KeyVault.Secrets, and Microsoft.Azure.Cosmos
• Cosmos DB partition key strategy is the most common trick question — understand hot partitions
• Build something real: a small API with App Service + Cosmos DB + Key Vault teaches more than any mock exam

The AZ-204 is Microsoft’s developer-focused Azure certification. It tests your ability to build, deploy, and maintain cloud applications using Azure services and SDKs. If you write code that runs on Azure, this is your cert.

Exam Domains

Domain	Weight	Key Focus
Develop Azure compute solutions	25–30% 🔥	App Service, Functions, Containers
Implement Azure security	20–25% 🔥	Managed identity, Key Vault, Entra ID
Develop for Azure storage	15–20%	Blob storage, Cosmos DB
Monitor, troubleshoot, and optimize	15–20%	App Insights, caching, CDN
Connect to and consume Azure services	15–20%	Service Bus, Event Grid, API Management

Core Services to Know Cold

Azure App Service

• Deployment slots, scaling rules, configuration settings
• Know the difference between appsettings in code vs. App Service Configuration
• Understand how slot swaps work and what settings are “sticky”

Azure Functions

• Triggers and bindings (HTTP, Timer, Queue, Blob)
• Durable Functions — orchestrator, activity, and entity patterns
• Cold start implications for Consumption vs. Premium plans

Azure Blob Storage

• Storage account types, access tiers (Hot, Cool, Archive)
• Lifecycle management policies
• SAS tokens and stored access policies — know when to use each

Azure Cosmos DB

• Partition key strategy — this is the most common gotcha
• Consistency levels: Strong → Eventual and the trade-offs
• RU estimation and capacity planning basics

Interview Angle — Cosmos DB

“Walk me through choosing a partition key” tests real understanding. The rule: pick a key with high cardinality (many distinct values) that aligns with your most common query. userId is usually better than status or country. A bad partition key creates a hot partition — all requests hammer one physical shard, defeating the distributed model.

Azure Key Vault

• Managed identities for authentication (system-assigned vs. user-assigned)
• Secrets, keys, and certificates — when to use each
• Key Vault references in App Service configuration

Interview Angle — Managed Identities

“How do you avoid hardcoding credentials?” is a perennial interview question. The answer: managed identities. Azure assigns a service principal to your compute resource; it authenticates to Key Vault (or other services) without any secrets in config or environment variables. System-assigned identities are tied to the resource lifecycle; user-assigned identities are reusable across multiple resources.

Study Approach That Worked

1. Microsoft Learn paths — Free, exam-aligned, and they include sandboxes
2. Build something real — I built a small API with App Service + Cosmos DB + Key Vault to internalize the patterns
3. Practice tests — MeasureUp official practice exams are closest to the real thing
4. Know the SDKs — The exam tests Azure.Storage.Blobs, Azure.Security.KeyVault.Secrets, Microsoft.Azure.Cosmos client libraries. Write code with them, don’t just read docs.

Exam Day Tips

• Time management: 60 questions in ~120 minutes. Don’t spend more than 2 minutes on any single question early on.
• Case studies: Read the requirements first, then the architecture. Most answers are in the requirements.
• Code snippets: They test real SDK usage. If you’ve written C# against these APIs, you’ll recognise the patterns.
• Flag and return: If a question feels 50/50, flag it and move on. Fresh eyes help.

What Surprised Me

The exam tested more Azure AD (now Entra ID) integration than I expected — especially around managed identities and MSAL authentication flows. Don’t skip the identity section.

Two other areas that caught me off guard: Durable Functions (orchestrator vs. activity function patterns appear more than you’d expect) and SAS token types (account SAS vs. service SAS vs. user delegation SAS — know when each applies).

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Last updated: March 2026. Exam objectives may change — always check the official skills outline.