Reference

Resources & study plan

The exam facts, a time-weighted plan, the official Microsoft materials, hands-on practice ideas, and a command quick reference to pull the five domains together.

Exam at a glance

Item	Detail
Exam code	AZ-400
Full name	Designing and Implementing Microsoft DevOps Solutions
Certification	Microsoft Certified: DevOps Engineer Expert
Prerequisite	AZ-104 or AZ-204 (needed for the certification, not to sit the exam)
Passing score	700 / 1000
Duration	~120 minutes
Questions	~40–60: multiple choice, case studies, drag-and-drop, build-list, hotspot, yes/no
Skills measured	Effective July 27, 2026
Renewal	Annual, free online assessment on Microsoft Learn

The prerequisite catches people out

You can take and pass AZ-400 without holding AZ-104 or AZ-204, but the DevOps Engineer Expert certification is only issued once you also hold one of those associate certifications. Plan the pair.

Weighting — where to spend your time

3 · Build & release pipelines50–55%

1 · Processes & communications10–15%

2 · Source control strategy10–15%

4 · Security & compliance10–15%

5 · Instrumentation strategy5–10%

A four-week study plan

Week	Focus	Do
1	Foundations + Domain 3 part A	Set up a free Azure DevOps org and a GitHub repo. Read Domain 1 & Domain 2. Build a first YAML pipeline (3.3) and package a library (3.1).
2	Domain 3 part B (the bulk)	Work through 3.2, 3.4, 3.5, 3.6. Deploy an app with slots, add an approval, deploy a Bicep template with `what-if`.
3	Security & instrumentation	Read Domain 4 & Domain 5. Configure OIDC to Azure, enable CodeQL and Dependabot, wire Application Insights and write a few KQL queries.
4	Consolidate & test	Drill the Exam Tips. Take the official practice assessment, revisit weak domains, redo the rapid-recap tables until automatic.

Hands-on beats reading

AZ-400 rewards people who have actually built pipelines. A free Azure DevOps organization (5 users, free Microsoft-hosted minutes) and a public GitHub repo (free Actions minutes) cost nothing. Building even a small CI/CD flow end-to-end cements more than any amount of reading.

Official Microsoft resources

Resource	Link
Exam page	AZ-400 exam
Study guide (skills measured)	Official study guide
Certification	DevOps Engineer Expert
Free practice assessment	Practice questions
Learning paths	Course AZ-400T00
Azure DevOps docs	learn.microsoft.com/azure/devops
GitHub Actions docs	docs.github.com/actions
Bicep docs	Bicep documentation
Azure Monitor docs	Azure Monitor documentation
DevOps resource center	learn.microsoft.com/devops
Exam sandbox	Try the exam UI

Command & tooling quick reference

Git recovery & history

git the ones that appear in questions

git revert <sha>                 # safe undo for pushed/shared commits
git reset --soft|--mixed|--hard  # local undo (rewrites history)
git reflog                        # find lost commits/branches (local, ~90 days)
git cherry-pick <sha>             # port one commit forward (release fixes)
git lfs track "*.psd"             # large files → LFS (commit .gitattributes!)
git filter-repo --path secret --invert-paths   # purge from all history
scalar clone <url>                # fast clone of a huge repo

Azure CLI — IaC & deployments

azure cli

az deployment group what-if -g RG --template-file main.bicep   # preview
az deployment group create  -g RG --template-file main.bicep   # incremental
az bicep decompile --file template.json                        # ARM → Bicep
az webapp deployment slot swap -g RG -n app --slot staging     # blue-green
az pipelines runs update --id $(Build.BuildId) --retention-lease-days 365
az artifacts universal publish --feed F --name pkg --version 1.0.0 --path .
az monitor metrics alert create --name CPU --condition "avg Percentage CPU > 80" ...

KQL — the patterns to know

KQL

requests
| where timestamp > ago(1h)                    // time filter
| where success == false                       // filter
| summarize count(), p95 = percentile(duration, 95) by bin(timestamp, 1h)
| order by p95 desc
| render timechart                             // visualise

Platform equivalents

Need	Azure Pipelines	GitHub Actions
Publish results on failure	`condition: succeededOrFailed()`	`if: always()`
Job ordering	`dependsOn`	`needs`
Matrix	`strategy: matrix`	`strategy: matrix` (+ `fail-fast`)
Manual with inputs	`parameters`	`workflow_dispatch`
Reuse	Templates / `extends`	Reusable workflows / composite actions
Secretless Azure auth	WIF service connection	OIDC + `id-token: write`
Cancel superseded runs	`pr: autoCancel`	`concurrency: cancel-in-progress`

More study notes

This is the rebuilt v2 of the AZ-400 notes. Find the wider collection of certification study notes on the author's study-notes hub, including the MS-102 notes that share this design.