Study Guide for Exam DP-420: Building AI Applications with Azure Cosmos DB

Note

We’re updating the certification’s name and level to reflect the evolving role of Azure Cosmos DB developers. The updated certification will be Microsoft Certified: Azure Cosmos DB AI Developer Associate. This change will go into effect on October 6, 2026. No action is required. Learn more.

Purpose of this document

This study guide should help you understand what to expect on the exam and includes a summary of the topics the exam might cover and links to additional resources. The information and materials in this document should help you focus your studies as you prepare for the exam.

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Updates to the exam

Our exams are updated periodically to reflect skills that are required to perform a role.

We always update the English language version of the exam first. Some exams are localized into other languages, and those are updated approximately eight weeks after the English version is updated. Other available languages are listed in the Schedule Exam section of the Exam Details webpage. If the exam isn't available in your preferred language, you can request an additional 30 minutes to complete the exam.

Note

The bullets that follow each of the skills measured are intended to illustrate how we are assessing that skill. Related topics may be covered in the exam.

Note

Most questions cover features that are general availability (GA). The exam may contain questions on Preview features if those features are commonly used.

Skills measured as of October 6, 2026

Audience profile

As an Azure Cosmos DB Developer Associate, you design, build, and optimize cost effective high-performance scalable applications that use Azure Cosmos DB including system of record for agent memory, conversation state, retrieval indexes, grounding data, and application data.

Your responsibilities include:

  • Designing and implementing data models and data distribution

  • Ingesting and querying data with Azure Cosmos DB database

  • Optimizing application performance, scalability, and cost

  • Implementing secure and production-ready applications

  • Building AI retrieval and RAG solutions

  • Designing and implementing agent memory systems

  • Integration of Azure Cosmos DB with Microsoft Fabric for analytical querying and operational insights

In this role, you collaborate with AI engineers, application developers, solution architects, data engineers, and security professionals to design and implement cost effective high-performance scalable applications.

You should have experience developing applications by using C# or Python. You should be familiar with Azure services, generative AI concepts, retrieval-based systems, and application development practices.

Skills at a glance

  • Design and develop database solutions (40–45%)

  • Secure, optimize, and deploy database solutions (30–35%)

  • Implement AI and Analytics capabilities in database solutions (20–25%)

Design and develop database solutions (40–45%)

Evaluate resource models and SDK solutions

  • Evaluate consistency levels

  • Evaluate Request Unit (RU) consumption requirements

  • Evaluating and configuring appropriate throughput

  • Configure account-level and container-level settings

  • Create and manage database and containers

  • Initialize SDK clients and connections

Implement database operations

  • Implement queries, parameterized queries, paging, and continuation tokens

  • Implement point read operations

  • Implement create, replace, update, patch and delete operations

  • Implement bulk, batch, and transactional operations

  • Configure Time to Live (TTL)

  • Implement concurrency control mechanisms

Design and implement data models and partitioning strategies

  • Design data models for access patterns and operational requirements

  • Design and select partition keys based on cardinality, access patterns, and write distribution requirements

  • Determine when to embed or reference related data

  • Evaluate the impact of partition key selection on scalability and performance

  • Implement hierarchical partition keys (HPKs) and multi-tenant partitioning strategies

  • Implement synthetic partition keys

  • Identify partitioning anti-patterns and partitioning issues during solution reviews

  • Estimate workload cost requirements

Implement change feed

  • Implement change feed operations

  • Differentiate between change feed processor and pull mode models

  • Configure lease containers

  • Implement change feed processing using latest mode or all versions and delete

  • Implement copy container jobs

Design and implement Azure Cosmos DB solutions by using AI-assisted tools

  • Implement Agent Kit to follow Azure Cosmos DB development recommended solutions

  • Implement Agent Kit to accelerate AI application development

Secure, optimize, and deploy database solutions (30–35%)

Implement database security controls

  • Configure authentication mechanisms

  • Configure authorization controls

  • Configure network security

  • Configure dynamic data masking

Implement availability and recovery solutions

  • Configure backup and restore solutions

  • Implement multi-region read and write configurations

  • Configure partition failover solutions

Optimize and remediate database performance

  • Optimize query performance

  • Analyze query performance metrics

  • Analyze index performance metrics

  • Monitor end-to-end latency against service objectives

  • Configure Azure Monitor alerts

  • Analyze diagnostic logs in Log Analytics

Implement Fleet management and monitoring across multiple accounts and subscriptions

  • Configure Fleet level throughput management

  • Configure Fleet monitoring with fleet analytics

Implement AI and analytics capabilities in database solutions (20–25%)

Design and implement AI retrieval

  • Design and implement full-text search

  • Design for vector data, including vector data type, vector indexes, and size

  • Design and implement vector partitioning and sharded DiskANN implementations

  • Implement vector search

  • Design and implement hybrid search

  • Optimize full-text and vector performance

  • Design and implement Retrieval-Augmented Generation (RAG)

Design and implement agent memory stores

  • Design durable memory stores

  • Implement conversation state

  • Implement semantic memory

Design and implement operational analytics on Azure Cosmos DB

  • Choose between Azure Cosmos DB and Cosmos DB in Microsoft Fabric

  • Configure and monitor data mirroring into Microsoft Fabric

  • Query Azure Cosmos DB mirrored JSON data in Microsoft Fabric with T-SQL and Spark

  • Read and write data into Azure Cosmos DB from Microsoft Fabric with Cosmos DB Spark connector

Study resources

We recommend that you train and get hands-on experience before you take the exam. We offer self-study options and classroom training as well as links to documentation, community sites, and videos.

Study resources Links to learning and documentation
Get trained Choose from self-paced learning paths and modules or take an instructor-led course
Find documentation Azure Cosmos DB documentation
Azure documentation
Ask a question Microsoft Q&A | Microsoft Docs
Get community support Analytics on Azure - Microsoft Tech Community
Azure Data Factory - Microsoft Tech Community
Azure - Microsoft Tech Community
Follow Microsoft Learn Microsoft Learn - Microsoft Tech Community
Find a video Exam Readiness Zone
Data Exposed
Browse other Microsoft Learn shows

Change log

The table below summarizes the changes between the current and previous version of the skills measured. The functional groups are in bold typeface followed by the objectives within each group. The table is a comparison between the previous and current version of the exam skills measured and the third column describes the extent of the changes.

Skill area prior to October 6, 2026 Skill area as of October 6, 2026 Change
Audience profile Major
Design and implement data models Design and develop database solutions % of exam increased
Design and implement a non-relational data model for Azure Cosmos DB for NoSQL Design and implement data models and partitioning strategies Minor
Design a data partitioning strategy for Azure Cosmos DB for NoSQL Removed
Plan and implement sizing and scaling for a database created with Azure Cosmos DB Evaluate resource models and SDK solutions Major
Implement client connectivity options in the Azure Cosmos DB SDK Removed
Implement data access by using the SQL language for Azure Cosmos DB for NoSQL Implement database operations Major
Implement data access by using Azure Cosmos DB for NoSQL SDKs Removed
Implement server-side programming in Azure Cosmos DB for NoSQL by using JavaScript Removed
Design and implement Azure Cosmos DB solutions by using AI-assisted tools New
Design and implement data distribution Removed
Design and develop database solutions Added
Design and implement a replication strategy for Azure Cosmos DB Implement availability and recovery solutions Major
Design and implement multi-region write Removed
Integrate an Azure Cosmos DB solution Removed
Design and develop database solutions Added
Enable Azure Cosmos DB analytical workloads Design and implement operational analytics on Azure Cosmos DB Major
Implement solutions across services Deleted
Optimize an Azure Cosmos DB solution Secure, optimize, and deploy database solutions % of exam increased
Optimize query performance when using the API for Azure Cosmos DB for NoSQL Optimize and remediate database performance Minor
Design and implement change feeds for Azure Cosmos DB for NoSQL Implement change feed Minor
Define and implement an indexing strategy for Azure Cosmos DB for NoSQL Optimize and remediate database performance Major
Implement Fleet management and monitoring across multiple accounts and subscriptions New
Maintain an Azure Cosmos DB solution Removed
Monitor and troubleshoot an Azure Cosmos DB solution Optimize and remediate database performance Major
Implement backup and restore for an Azure Cosmos DB solution Implement availability and recovery solutions Major
Implement security for an Azure Cosmos DB solution Implement database security controls Minor
Implement data movement for an Azure Cosmos DB solution Deleted
Implement a DevOps process for an Azure Cosmos DB solution Deleted
Implement AI and analytics capabilities in database solutions New
Design and implement AI retrieval New
Design and implement agent memory stores New
Design and implement operational analytics on Azure Cosmos DB New