Azure DevOps Engineer Expert (AZ-400) prep, adaptive plan with ARIA
AZ-400 is Microsoft's expert-tier DevOps cert. The prerequisite is AZ-104 (admin) or AZ-204 (developer). The exam tests CI/CD pipeline design, secure infrastructure-as-code, branch strategies, telemetry, and process automation across both Azure DevOps and GitHub. 150 minutes, with a mix of multiple choice and case studies.
What the exam is
Five objectives. The build and release pipelines domain is the headline, accounting for nearly half the score.
| Domain | Weight |
|---|---|
| Design and implement processes and communications | 10-15% |
| Design and implement a source control strategy | 15-20% |
| Design and implement build and release pipelines | 40-45% |
| Develop a security and compliance plan | 10-15% |
| Implement an instrumentation strategy | 10-15% |
Passing score 700 out of 1000.
How 
ARIA preps you for it
The CAT eval lands a per-domain skill estimate after fifteen to twenty-five questions. Most candidates land heavy on Build and Release Pipelines (the 40-45% domain), because YAML pipeline syntax, multi-stage gates, and approval workflows are unforgiving on edge-case behavior. The roadmap weights phases to your real gaps.
The error backlog tags every miss by service area (Azure Pipelines, Repos, Artifacts, Boards, GitHub Actions, Key Vault) and returns it on the standard 3-day, 7-day, 21-day schedule.
Common pitfalls on this cert
Memorizing classic Release Pipelines while skipping YAML. Microsoft is migrating everyone to YAML-defined pipelines. Classic UI questions still appear, but YAML is the heavier scoring surface.
Underestimating branch policy questions. Branch policies, required reviewers, and build validation rules show up in every domain.
Skipping GitHub Actions because the cert says "Azure DevOps". AZ-400 covers GitHub Actions in roughly a third of the pipeline questions. Treat them as one tool family.
Prerequisite
AZ-400 expects you to already hold AZ-104 or AZ-204. Microsoft also recommends two years of Azure experience plus one of the associate certs. Sitting it cold is a wall.
The pass guarantee
Same five conditions as every cert: all milestones done, all phases done, two mocks at target or above, one gauntlet at eighty, live readiness eighty or higher. Sit AZ-400 inside the 60-day window after eligibility, fail, get a full refund of the Exam Ready plan.