Microsoft · Intermediate

Microsoft Azure Cosmos DB Developer Specialty (DP-420) (DP-420) practice exam & study guide

Microsoft DP-420 (Azure Cosmos DB Developer Specialty) is a certification for developers who design and build cloud-native applications on Azure Cosmos DB for NoSQL. It validates expertise in data modeling, partitioning, the SDK and SQL query language, and operating a Cosmos DB solution.

DP-420 is a hands-on developer specialty. Questions expect you to read C#/Java code, write efficient NoSQL queries, design partition keys, and reason about request-unit (RU) cost and consistency.

This free hub gives you everything you need to prepare: a syllabus breakdown by exam domain, realistic practice questions with teacher-style explanations, a glossary of the Cosmos DB concepts the exam relies on, and full-length timed mock exams that mirror the real testing experience.

60
Questions
120 min
Time limit
70%
Mock pass %
5
Domains

Start studying DP-420

New here? Follow the three steps below in order. Everything is free and needs no account.

  1. 1
    Learn the plan

    See all 5 domains in exam-weight order.

    Open study path
  2. 2
    Drill by domain

    Practice one topic at a time with explained answers.

    Start with the first domain
  3. 3
    Sit a timed mock

    60 questions · 120 min · 70% to pass our mock.

    Take the mock exam

All DP-420 study resources

DP-420 exam domains

The DP-420 exam is weighted across 5 domains. Pick any domain below to drill it — or read the full breakdown in the FAQ.

Exam domainExam weightPractice
Design and implement data models38%Practice this topic
Design and implement data distribution8%Practice this topic
Integrate an Azure Cosmos DB solution8%Practice this topic
Optimize an Azure Cosmos DB solution18%Practice this topic
Maintain an Azure Cosmos DB solution28%Practice this topic

Sample DP-420 questions

A sample of the DP-420 questions on this hub. Each links through to the full question, the correct answer, and an explanation of why every other option is wrong.

Key DP-420 terms

Start with these terms, then explore the full glossary. Each links to a plain-English definition written for the DP-420 exam.

DP-420 frequently asked questions

What is the DP-420 certification?+

DP-420 is Microsoft’s specialty certification for Azure Cosmos DB, aimed at developers building globally distributed, low-latency applications.

It is deep rather than broad: nearly all of the exam is about one service, so success rewards genuine hands-on experience with the Cosmos DB for NoSQL API.

What topics are on the DP-420 exam?+

The DP-420 exam is organised into five weighted domains. Microsoft publishes each as a range (35–40%, 5–10%, 5–10%, 15–20%, 25–30%); the single percentages below are our study weights within those ranges, so bias your study toward the heavier domains — Design and implement data models is by far the largest, followed by Maintain an Azure Cosmos DB solution.

Design and implement data models (38%)

The largest domain. Covers non-relational modeling (embedding vs referencing, denormalization), partitioning strategy and partition-key choice (including synthetic and hierarchical keys), sizing and scaling (serverless, provisioned, autoscale, RU throughput), SDK connectivity, the SQL query language, and server-side JavaScript.

Design and implement data distribution (8%)

Covers global distribution and when to use it, automatic and manual failover, the five consistency levels and their availability/latency/RU trade-offs, multi-region writes, and custom conflict-resolution policies.

Integrate an Azure Cosmos DB solution (8%)

Covers analytical workloads (analytical store, Microsoft Fabric mirroring — the current recommended path for new projects — and change data capture) and integrating across services with the change feed and Azure Functions for denormalization, referential integrity, aggregation, and archiving.

Optimize an Azure Cosmos DB solution (18%)

Covers query performance and RU-cost reduction, the integrated cache, change-feed design with Azure Functions and the change-feed estimator, and defining an indexing strategy including composite indexes and read- vs write-heavy policies.

Maintain an Azure Cosmos DB solution (28%)

Covers monitoring and troubleshooting (status codes, Normalized RU Consumption, latency metrics, Azure Monitor alerts and logs), backup and restore (periodic vs continuous, point-in-time), security (managed vs customer-managed keys, RBAC, Microsoft Entra ID, Always Encrypted), data movement, and DevOps with ARM templates.

Is the DP-420 hard?+

DP-420 is hard because it is a deep, code-level specialty: you must design partition keys, write and cost NoSQL queries, and reason about consistency and RU budgets under realistic constraints.

The heavy weighting on data modeling means partitioning mistakes cost you the most. The challenge is genuine developer fluency with Cosmos DB, which is why hands-on practice matters.

How many questions are on the DP-420 exam and how long is it?+

DP-420 typically presents 40 to 60 questions, which may include case studies and multiple formats, and is scored from 100 to 1000.

Our full-length practice mock uses a 60-question, 120-minute session so you can rehearse pacing across all five domains before test day.

What score do you need to pass the DP-420?+

Microsoft scores DP-420 on a scale of 100 to 1000, and you need 700 to pass. Because it is scaled, questions are not all worth the same and there is no penalty for guessing, so answer everything. Our practice mock uses a 70% threshold as a study checkpoint; aim comfortably beyond it before test day.

How much does the DP-420 exam cost?+

The DP-420 exam fee is set by Microsoft and varies by region — check the Microsoft site for current pricing. As a Microsoft specialty certification, it can be renewed for free on Microsoft Learn before it expires. Everything on this hub is free.

Who should take the DP-420?+

DP-420 is aimed at software developers who build applications on Azure Cosmos DB for NoSQL and are comfortable with C# or Java, SQL-style queries, JSON, and PowerShell.

There is no formal prerequisite, but you should have real experience developing apps for Azure before attempting it.

What jobs and salaries can the DP-420 lead to?+

DP-420 maps to roles such as cloud application developer, backend engineer, and data platform developer working with NoSQL at scale.

How much any certification affects pay depends heavily on geography, seniority, and experience, so treat any single salary figure with caution. DP-420 is best viewed as proof of specialized Cosmos DB development skill.

How long does it take to study for the DP-420?+

Developers with some Azure experience often need four to eight weeks, with most of that time spent building and querying real Cosmos DB containers.

Review every explanation, including for questions you answered correctly, because DP-420 distractors are built from plausible but sub-optimal design choices. Use the per-domain results here to find your weakest area, then finish with full-length timed mocks.

How should you prepare for the DP-420?+

Study the five domains above, giving the heaviest weight to data modeling, then drill scenario questions domain by domain while practicing with a real Cosmos DB account or the emulator. Every MockAPI question reveals a full explanation and tells you why each wrong answer is wrong.

When you can design a partition key and cost a query comfortably, move to full-length timed mocks. Use the glossary to keep concepts like RU, logical partition, consistency levels, and the change feed straight, and aim to score consistently above the checkpoint before you book.

Can you take the DP-420 exam online?+

Yes. Microsoft delivers DP-420 through Pearson VUE, so you can test at a physical Pearson VUE centre or online with remote proctoring. The online exam requires a private, quiet room, a clear workspace, a webcam and microphone, a stable connection, and government-issued photo ID, with a proctor monitoring you and a room scan before you start.

If you do not pass, Microsoft requires a 24-hour wait before a second attempt and a 14-day wait before subsequent attempts, with a limit per year.

What certification should you take after the DP-420?+

After DP-420, developers often broaden with Azure developer or data certifications such as AZ-204 or the Fabric analytics tracks, depending on their focus.

For many, the real next step is shipping a production Cosmos DB application. Pairing DP-420 with hands-on delivery is what turns the certificate into a career.