Microsoft · DP-420
Microsoft Certified: Azure Cosmos DB Developer Specialty (DP-420) Practice Tests
Write efficient queries, create indexing policies, manage, and provision resources in the SQL API and SDK with Microsoft Azure Cosmos DB.
Exam Details
Practice Questions
677
≈ 13 practice exams
Duration
100 minutes
Passing Score
700/1000
Difficulty
SpecialtyLast Updated
Jan 2025
Topics Covered
Design and implement data modelsDesign and implement data distributionIntegrate an Azure Cosmos DB solutionOptimize an Azure Cosmos DB solutionMaintain an Azure Cosmos DB solution
Microsoft Certified: Azure Cosmos DB Developer Specialty (DP-420) Practice Exam Preparation
Use this DP-420 practice exam to prepare for Microsoft Certified: Azure Cosmos DB Developer Specialty (DP-420) with realistic questions, detailed explanations, and focused study modes. The practice bank includes 677 questions for Microsoft DP-420, so you can review the exam steadily instead of relying on one long cram session.
As you practice, pay extra attention to recurring topics such as Design and implement data models, Design and implement data distribution, Integrate an Azure Cosmos DB solution, Optimize an Azure Cosmos DB solution, and Maintain an Azure Cosmos DB solution. Start with short sessions to identify weak areas, then move into timed quizzes once your accuracy is consistent.
The explanations are especially useful when you want to connect exam wording to the responsibilities and scenarios described in the official certification guidance. Use the free preview first, then unlock the full question bank when you are ready to build a complete study routine.
Exam Domain Breakdown
Design and implement data models38%
Design and implement data distribution8%
Integrate an Azure Cosmos DB solution8%
Optimize an Azure Cosmos DB solution18%
Maintain an Azure Cosmos DB solution28%
Exam Overview
The Microsoft Certified: Azure Cosmos DB Developer Specialty (DP-420) validates subject matter expertise in designing, implementing, and monitoring cloud-native applications that store and manage data using Azure Cosmos DB. The certification covers the full development lifecycle: modeling non-relational data, selecting partition keys, managing throughput and scaling, implementing the SQL API and .NET/Java SDKs, writing server-side JavaScript (stored procedures, triggers, user-defined functions), and integrating Cosmos DB with other Azure services such as Azure Functions, Azure Synapse Link, and Event Hubs.
The exam was last updated on January 27, 2025, and reflects current platform capabilities including hierarchical partition keys, the integrated cache, Always Encrypted, and Azure Synapse Link with Change Data Capture. Candidates are assessed on their ability to optimize query performance through indexing strategies and cost analysis, implement change feeds, configure backup and restore, enforce security controls using Microsoft Entra ID and Azure RBAC, and automate operations using Azure Resource Manager templates and PowerShell/CLI.
Who Should Take This Exam
This certification is intended for developers and data engineers with hands-on experience building Azure applications that rely on Azure Cosmos DB for NoSQL as their primary data store. Suitable job titles include Azure Developer, Cloud Application Developer, and Data Engineer. Candidates typically have two or more years of experience working with Azure services and are comfortable reading C# or Java application code, writing SQL queries for the Cosmos DB NoSQL API, and interpreting JSON documents.
Professionals pursuing this certification often work in roles where they are responsible for both the data modeling decisions and the operational health of a Cosmos DB solution—including security, availability, resilience, and performance. It is particularly relevant for those building globally distributed, high-throughput applications such as IoT platforms, e-commerce systems, and real-time analytics pipelines.
Prerequisites
Microsoft does not enforce formal prerequisites for DP-420, but candidates are expected to have practical experience developing applications for Azure and working with Azure Cosmos DB database technologies. Specifically, candidates should be proficient with the Azure Cosmos DB for NoSQL API, able to write efficient SQL queries against it, create and tune indexing policies, and use the Azure Cosmos DB SDK (C# or Java). Familiarity with JSON structure and the ability to write server-side JavaScript for stored procedures and triggers is also required.
A solid understanding of Azure fundamentals—including resource provisioning, Azure role-based access control (RBAC), Azure Monitor, and ARM templates—is strongly recommended. Candidates who have completed the AZ-900 (Azure Fundamentals) or AZ-204 (Azure Developer Associate) certification will find much of this background knowledge directly applicable. Microsoft's free learning path DP-420T00 (Design and Implement Cloud-Native Applications with Azure Cosmos DB) is the official preparatory course.
Exam Format
Exam DP-420 is a proctored assessment delivered through Pearson VUE, available both online (remote proctored) and at Pearson VUE test centers. Candidates are given 100 minutes to complete the exam. The number of questions is not publicly disclosed and may vary, but the exam may include multiple question types such as multiple choice, drag-and-drop, build-list, case studies, and interactive lab components. A score of 700 or higher on a scale of 100–1000 is required to pass.
The exam is available in English, Japanese, Chinese (Simplified), Chinese (Traditional), Korean, German, French, Spanish, Portuguese (Brazil), and Italian. If taking the exam in a non-English localization, candidates may request an additional 30 minutes. The certification expires annually and can be renewed at no cost by passing a free online assessment on Microsoft Learn. The exam price is approximately $165 USD, varying by country or region of the testing location.
Skills Measured
- 1.Design and implement data models (35–40%): Covers non-relational data modeling for the NoSQL API including multi-entity containers, document denormalization, reference patterns, TTL configuration, document versioning, and schema versioning. Also includes partitioning strategy selection, synthetic and hierarchical partition keys, throughput sizing (serverless vs. provisioned), SDK client connectivity (gateway vs. direct mode), SQL query implementation (arrays, aggregation, subqueries, functions), SDK CRUD and patch operations, transactional batch, optimistic concurrency with ETags, session consistency, pagination, and server-side JavaScript (stored procedures, triggers, UDFs).
- 2.Design and implement data distribution (5–10%): Covers global replication strategy including automatic and manual failover policies, consistency model selection (strong, bounded staleness, session, consistent prefix, eventual) and their trade-offs in latency, availability, and RU cost. Also includes multi-region write configuration and custom conflict resolution policies for the NoSQL API.
- 3.Integrate an Azure Cosmos DB solution (5–10%): Covers enabling and querying Azure Synapse Link for analytical workloads, choosing between Synapse Link and the Spark Connector, implementing custom partitioning in Synapse Link, Change Data Capture in the analytical store, and time travel. Also includes integration patterns using Azure Functions with Change Feed for denormalization, referential integrity, aggregation, and archiving, as well as Azure AI Search integration and Event Hubs eventing.
- 4.Optimize an Azure Cosmos DB solution (15–20%): Covers query performance tuning through index adjustments, RU cost calculation for queries and point operations, use of the Azure Cosmos DB integrated cache, change feed processing via Azure Functions triggers and SDK consumers, change feed estimator for scaling, and defining indexing strategies (read-heavy vs. write-heavy, composite indexes, custom indexing policies).
- 5.Maintain an Azure Cosmos DB solution (25–30%): Covers monitoring with Azure Monitor (normalized RU usage, server-side latency, partition distribution, replication metrics), configuring alerts and diagnostic logs, implementing periodic and continuous backup, point-in-time recovery, and security controls including network access, encryption (service-managed and customer-managed keys, Always Encrypted), Microsoft Entra ID data plane access, Azure RBAC for control plane, CORS, Key Vault key management. Also includes data movement strategies (SDK bulk, Azure Data Factory, Kafka connector, Stream Analytics, Spark Connector, IoT Hub) and DevOps automation with ARM templates and PowerShell/CLI.
Study Tips
- Use the official Microsoft Learn learning path DP-420T00 (Design and Implement Cloud-Native Applications with Azure Cosmos DB) as your primary study resource—it maps directly to exam domains and includes hands-on sandbox exercises for SDK operations, indexing, and partitioning.
- Take the free official Practice Assessment on Microsoft Learn (Assessment ID 104) multiple times. It mirrors the style and difficulty of real exam questions and provides explanations that link back to documentation—use it to identify weak domains before exam day.
- Set up a free-tier Azure Cosmos DB account and the Azure Cosmos DB Emulator for offline development. Practice writing NoSQL API queries, configuring composite indexes via the Data Explorer, implementing stored procedures in JavaScript, and using the .NET or Java SDK to perform batch and patch operations.
- Focus significant study time on partitioning and indexing—together these two sub-domains underpin both the Design and implement data models domain (35–40%) and the Optimize domain (15–20%). Work through partition key selection scenarios, calculate RU costs for cross-partition queries, and experiment with custom indexing policies to understand read/write trade-offs.
- Study consistency models in depth: understand the five levels (strong, bounded staleness, session, consistent prefix, eventual), their RU cost implications, latency characteristics, and when to override the account-level consistency at the per-request level using SDK request options.
- Review the Maintain domain (25–30%) carefully—it is the second-largest domain. Practice configuring Azure Monitor diagnostic settings, setting up alerts for 429 (rate-limited) requests, and walking through both periodic and continuous backup/restore workflows in the Azure portal.
- Consult the official DP-420 Study Guide on Microsoft Learn (aka.ms/dp420-StudyGuide) to review the full list of objectives as of January 27, 2025. Pay particular attention to recently added topics such as Always Encrypted, hierarchical partition keys, and Synapse Link Change Data Capture, which reflect the latest exam update.
Career Benefits
Earning the Azure Cosmos DB Developer Specialty positions professionals for roles such as Senior Azure Developer, Cloud-Native Application Architect, and Data Platform Engineer—positions that command premium salaries due to the specialized nature of globally distributed database design. According to industry surveys, Azure-certified developers with specialty credentials typically earn between $120,000 and $165,000 USD annually in North American markets, with variation by region and total experience. Demand for Cosmos DB expertise is driven by enterprises building IoT, gaming, retail, and financial services applications that require low-latency, multi-region access at scale.
Compared to the broader AZ-204 (Azure Developer Associate), DP-420 demonstrates deep, focused expertise in a specific high-value technology—making it particularly compelling on a resume for organizations heavily invested in the Azure data platform. The certification is recognized globally and renewable annually at no cost, ensuring that credential holders remain current with platform evolution. It also pairs well with certifications such as DP-203 (Azure Data Engineer Associate) for professionals who straddle application development and data engineering responsibilities.
Sample Questions
5 sample questions with answers and explanations. The full bank has 677 questions, enough for 13 full-length practice exams.
Preview — answers shown1. DisasterRecovery Corp has an Azure Cosmos DB account named recoveryaccount with multi-region write enabled and periodic backup configuration. They need to configure point-in-time restores (PITRs) for the past seven days. What two actions must they perform? (Select two!)
Multiple correct answersAChange the backup policy to continuous mode
BDisable multi-region writes for the account
CIncrease the backup retention period setting
DConfigure backup storage redundancy options
EEnable availability zones in all regions
FSet up cross-region backup replication
Explanation
Point-in-time restores require continuous backup mode, which is incompatible with multi-region write accounts. First, the account must be converted from multi-region writes to single-region writes, then the backup policy must be changed from periodic to continuous mode. Continuous backup automatically provides a minimum seven-day retention period, meeting the requirement. Backup retention, storage redundancy, and backup replication settings are not applicable since they relate to periodic backup features. Availability zones provide within-region redundancy but don't affect backup mode compatibility. The fundamental requirement is switching to continuous backup, which necessitates disabling multi-region writes first.
2. RegionalApp Corp needs to specify region configuration for global distribution across their multi-tier application. They have web applications in East US and West Europe, mobile APIs in Southeast Asia, and batch processing in Central US. Each tier has different latency requirements and data consistency needs. How should they specify regions for optimal global distribution?
AConfigure all application tiers to connect to their geographically nearest Azure Cosmos DB regions for minimum latency
BUse a single primary region (East US) for all applications to ensure data consistency with read replicas in other regions
CConfigure dynamic region selection based on current performance metrics and regional availability
DImplement tier-specific region configurations with web apps using local regions and batch processing using cost-optimized regions
Explanation
Configuring each application tier to connect to their geographically nearest regions provides optimal latency and performance for global distribution. This approach leverages Azure Cosmos DB's multi-region capabilities effectively while maintaining good performance for all application tiers. A single primary region would create unnecessary latency for distant applications. Tier-specific configurations might optimize costs but could compromise performance for some tiers. Dynamic region selection adds complexity without significant benefits over geographic proximity and could create unpredictable performance patterns that are difficult to troubleshoot and optimize.
3. ReadOptimize Corp has an Azure Cosmos DB for NoSQL account with read-heavy workloads. They want to implement integrated caching to improve read performance. What should they do first?
AEnable Azure Synapse Link for analytical workloads
BConfigure Azure Cache for Redis integration
CEnable multi-region reads with automatic failover
DCreate a dedicated gateway for the account
Explanation
Creating a dedicated gateway is the mandatory first step for enabling Azure Cosmos DB integrated cache. The dedicated gateway provides the infrastructure layer where the integrated cache operates, intercepting read requests and serving cached responses when possible. The integrated cache is built into the dedicated gateway service and cannot function without it. Azure Synapse Link enables analytical capabilities but doesn't provide transactional read caching. Azure Cache for Redis is a separate caching service and not the same as Cosmos DB's integrated cache feature. Multi-region reads improve availability and performance but don't provide the same request-level caching benefits as the integrated cache. The dedicated gateway is the foundational requirement for integrated caching functionality.
4. DataEncryption Solutions Inc needs to configure data encryption for their Azure Cosmos DB account handling financial transactions and customer data. They need encryption at rest, in transit, and field-level encryption for sensitive data elements like credit card numbers and social security numbers. What comprehensive encryption strategy should they implement?
AUse Azure Cosmos DB default encryption at rest and HTTPS for transport, with application-level encryption for sensitive fields
BImplement customer-managed keys for encryption at rest, enforce HTTPS/TLS for transport, and use Always Encrypted for field-level protection
CConfigure service-managed encryption for all scenarios and rely on network security for additional protection
DUse transparent data encryption with Azure Key Vault integration and implement custom field-level encryption logic
Explanation
Customer-managed keys for encryption at rest provide enhanced control and compliance capabilities for financial data, HTTPS/TLS ensures secure data transmission, and Always Encrypted provides robust field-level protection for sensitive data elements. This comprehensive approach addresses all encryption requirements for financial services. Application-level encryption for sensitive fields doesn't provide the same level of integration and key management as Always Encrypted. Service-managed encryption alone doesn't provide the control required for financial data compliance. Transparent data encryption is not a Cosmos DB feature, and custom encryption logic adds complexity without providing benefits over Always Encrypted.
5. StorageLimitation Corp is evaluating throughput models for their document management system that will store large amounts of archived documents and media files. They project storage needs of 5TB within the first year, with potential growth to 20TB over three years. Which throughput model can accommodate their storage requirements?
ADatabase-level shared throughput to distribute storage costs across multiple containers
BServerless throughput since it offers the most cost-effective storage pricing
CProvisioned throughput for unlimited storage capacity to support projected growth
DAutoscaling throughput to match storage scaling with throughput scaling automatically
Explanation
Provisioned throughput supports unlimited storage capacity, which is necessary for the projected 5-20TB storage requirements. Serverless has a maximum storage limit of 1TB per container, which would be exceeded in the first year. While autoscaling is a form of provisioned throughput that could work, the fundamental requirement is storage capacity, which eliminates serverless due to its 1TB limit. Database-level sharing affects throughput allocation and costs but doesn't change the underlying storage capacity limits of different throughput models. Only provisioned throughput (including autoscaling variants) can handle the unlimited storage growth projected.
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