What Is the Microsoft Online Assessment (OA)?

The Microsoft online assessment is a timed coding test you take alone, before any live interview. Candidates and recruiters shorten it to OA.

It is usually two or three problems in 60 to 90 minutes. You write code in a browser, and hidden test cases grade it. No interviewer watches.

It is a screening step. Microsoft uses it to cut a large applicant pool down to the people worth a live round.

Most online assessments go to students, interns and new graduates. Experienced candidates often skip it and start with a live technical screen.

What the test looks like

Part	What candidates report
Number of problems	2 or 3, sometimes 1 for intern roles
Time limit	60 to 90 minutes for the whole test
Difficulty	Easy to medium, one harder problem at the end
Languages	C++, Java, Python, C#, JavaScript and others
Platform	A hosted coding site, named in the invitation email
Grading	Hidden test cases, run after you submit
Extra parts	Sometimes short multiple-choice questions on complexity

The invitation usually gives you three to seven days to start. Once you open the test, the clock does not stop.

Microsoft does not publish a passing score. Candidates report that clean, fully passing solutions to two problems is the usual bar.

Arrays, strings and hash maps carry most of the test. These appear in nearly every report.

Trees, sorting and simple graph traversal come next. Heavy dynamic programming is less common than at some other companies.

Efficiency matters because the test cases are large. A correct solution that times out scores the same as a wrong one.

Edge cases are where most people lose points. Empty input, a single element, duplicate values and very large values all appear in the hidden tests.

There is no partial credit for explaining yourself. The grader only sees the output.

There is no hint when you stall. You have to spot your own mistake and move on.

So the skill is different. Speed and self-testing matter more than discussion.

You will not get your score. Microsoft rarely shares the result of the test itself.

Candidates report waiting one to three weeks for the next step. A pass leads to a live technical screen, then the full loop.

Silence past three weeks is common and is not always a rejection. University hiring runs in batches, and teams are matched later.

If you do not pass, you can usually apply again in the next hiring cycle.

Learn the patterns, not single problems. A small set of shapes covers most questions. Grokking the Coding Interview is built around them.
Cover the data structures first. Arrays, strings, hash maps and trees pay back most. Grokking Data Structures for Coding Interviews works through each one.
Practice with a timer from day one. Give yourself 30 minutes per problem, then 20. The test is as much about pace as about logic.
Write your own test cases before you submit. Empty input, one element, duplicates and the largest allowed value. This single habit lifts scores the most.
Do a short focused set if the date is close. Grokking the 75 Top Coding Interview Questions and Grokking the Microsoft Coding Interview both fit a tight week.
Plan the rounds after the test. What to expect in a Microsoft technical interview and what questions does Microsoft ask cover the live stages.
Read the process end to end once. The Microsoft interview guide puts every stage in order, from the first email to the offer call.
Keep a short error log. Write down every problem you failed and the reason. Reviewing that list is worth more than solving new problems in the last week.