AZ-400 prerequisites and exam tips
To earn the DevOps Engineer Expert certification, Microsoft requires that you pass AZ-400 and also hold the Azure Administrator Associate or the Azure Developer Associate certification. The Azure Developer Associate certification has since been retired, so for anyone starting now the realistic prerequisite is Azure Administrator Associate, earned with AZ-104. Microsoft also expects practical experience on both GitHub and Azure DevOps.
What Microsoft says about prerequisites
| Item | What the official pages state |
|---|---|
| Required exam | AZ-400 |
| Required associate certification | Azure Administrator Associate or Azure Developer Associate (at least one) |
| Azure Developer Associate status | Microsoft’s page marks the certification and its renewal assessment as retired |
| Experience | Administering and developing in Azure, with strong skills in at least one; implementing both GitHub and Azure DevOps solutions |
| Role | Developer or infrastructure administrator on a cross-functional team |
Check the DevOps Engineer Expert page on Microsoft Learn before booking, because certification rules change and the page is the authority. If you hold neither associate credential, AZ-104 is the straightforward way to meet the requirement, and AZ-104 vs AZ-305 shows how it fits with the architect route.
What experience helps
You do not need all of this on day one, but each item removes a gap:
- Writing YAML pipelines in Azure Pipelines and GitHub Actions, including templates and environments.
- Using Git beyond commit and push: rebasing, cherry-picking, recovering from mistakes.
- Deploying Azure resources with Bicep or ARM templates and the Azure CLI.
- Basic Azure administration: identities, role assignments, networking and App Service, which is exactly what AZ-104 tests.
- Reading logs and writing a short KQL query.
If the architect route is also on your list, AZ-305 vs AZ-400 compares the two expert exams.
Exam tips
Weight your time by weight. More than half the marks are pipelines. Spend half your study time writing and debugging pipelines, not reading about them.
Know both products. Many questions give one side of a pair and expect the other: branch policy and branch protection rule, environment approval and GitHub environment reviewer, variable group and GitHub variables or secrets, template and reusable workflow, service connection and federated credential.
Read YAML like a reviewer. Check the trigger, the dependsOn, the condition and the pool before reading the steps. Many wrong answers differ by one keyword.
Prefer secretless and managed options. When a scenario mentions credentials, an option using federation, managed identity or Key Vault usually beats one with stored secrets.
Match strategy to the constraint. Instant rollback points to blue-green or slots; limited exposure points to canary or ring; separating deployment from release points to feature flags.
Do not over-read the portal. Menus and blade names change. The exam asks which feature or setting meets a requirement.
Use Microsoft Learn sparingly. On role-based exams you can open Learn in the exam window, but the clock runs. Use it for a single detail, such as a parameter name.
Practise under time. Do the free practice test in one sitting and review the explanations afterwards. For the day itself, see the exam day guide.