Microsoft AB-400 Real Exam Questions [October 2026 Update]

AB-400 is not simply a renumbered PL-400. The exam replaces PL-400 from October 16, 2026, and while the core server-side extensibility domain (Dataverse plug-ins, custom APIs, PCF components, Dataverse Web API) remains unchanged at the top weighting, AB-400 adds an entirely new category of assessed skills that PL-400 never tested: agentic AI as part of the solution developer’s core responsibility.

Microsoft Foundry agents and Copilot Studio integration move from optional platform awareness to exam-assessed developer skills in the Extend Microsoft Power Platform domain – the largest domain at 35-40%. The exam now tests building agents by code, integrating them with Dataverse data via Work IQ, and exposing them through Model Context Protocol (MCP) servers that Copilot agents can discover and call. These are not peripheral features the exam tests at awareness level; they are implemented developer skills requiring code-level understanding of how agents interact with Dataverse APIs, how MCP server tool registrations work, and how custom agent logic integrates with the broader Power Platform.

The practical consequence for PL-400 holders and candidates is clear: study materials written before 2026 are incomplete for AB-400. The plug-in and PCF knowledge transfers fully. The client scripting, connector, and ALM knowledge transfers fully. The agentic AI and MCP content does not transfer from any prior PL-400 preparation – it must be studied fresh from the current AB-400 skills outline and Microsoft Learn documentation.

Exam Snapshot

PL-400 vs. AB-400 – What Changed

Three PL-400 domains collapse into one. The user experience domain more than doubles in weight. Agentic AI goes from absent to assumed.

Domain 1: Build Microsoft Power Platform Solutions (15-20%)

This domain consolidates what PL-400 assessed across three separate domains – technical design, Dataverse configuration, and Power Apps creation – into one foundational solutions domain.

Technical architecture decisions: Choosing where business logic belongs – whether logic runs in cloud flows, client-side scripts, Dataverse business rules, plug-ins, or Azure Functions – based on execution context, performance requirements, user dependency, and testability. The exam tests this as a contextual decision: logic that must execute regardless of the client belongs in a plug-in; logic that should run only in specific UI contexts belongs in client scripts; logic that involves external services belongs in flows or Azure Functions.

Dataverse table type selection: Standard tables for transactional relational data with full Dataverse features (security, auditing, relationships). Virtual tables for external data surfaced inside Dataverse without replication – queried through an external data provider at runtime. Elastic tables for high-volume, high-velocity data where document-style storage is more appropriate than relational rows.

Solution management and ALM: Environment variables (store configuration values that differ between environments, referenced without hard-coding connection strings or IDs in logic), solution layers (how customisations stack across base solutions and customisations and which layer wins on conflict), Power Platform Pipelines (automated deployment between development, test, and production environments within the same tenant), and Power Platform Build Tools (CI/CD pipeline tasks for Azure DevOps and GitHub Actions).

Microsoft Foundry vs. Copilot Studio decision: The exam tests when each agent-building platform is the correct choice – Copilot Studio for maker-configured, low-code conversational agents; Microsoft Foundry for developer-built agents requiring custom code, advanced orchestration, and direct API integration that Copilot Studio cannot express.

Domain 2: Extend the User Experience (25-30%)

The UX domain more than doubles in weight from PL-400 to AB-400 – from 10-15% to 25-30% – reflecting Microsoft’s shift toward richer client-side development including Power Apps code apps as a first-class developer output.

Power Apps Code Apps

Power Apps code apps are full React-based custom applications hosted within the Power Platform environment – not canvas apps with Power Fx formulas, but fully custom web applications with their own component architecture, deployed to and integrated with Power Platform. The exam tests code app creation, connection configuration to Dataverse and external data sources, integration of cloud flows, agents, and environment variables within code app logic, and device and Web API feature usage within code apps.

This is a genuinely new developer surface that did not exist in PL-400. Candidates need hands-on familiarity with code app tooling and the Power Apps CLI commands used to initialise, build, and deploy them.

Power Apps Component Framework (PCF)

PCF components extend the standard Dataverse form field controls with custom-rendered UI components – field components replace a single field’s rendering, dataset components replace a grid or subgrid. PCF components are built using TypeScript and React, packaged with the Power Apps CLI, and deployed through solutions.

The exam tests PCF component lifecycle methods (init(), updateView(), getOutputs(), destroy()), the context object (which provides the component with field values, formatting utilities, the Web API for Dataverse access, device capabilities, and utility functions), and the manifest descriptor that declares the component’s properties, resources, and feature requirements.

Client Scripting in Model-Driven Apps

Client scripts execute JavaScript in the browser when form events fire – OnLoad (form open), OnSave (before record save), OnChange (field value changes), and tab/section show/hide events. Scripts access the form context through the formContext object – reading and writing field values, controlling field disabled state, managing form notifications, and calling Dataverse web API from the client.

The exam tests client script execution order for multiple registered handlers, the correct API for retrieving related record values (the Xrm.WebApi.retrieveMultipleRecords() pattern), and the distinction between synchronous form context operations and the asynchronous Web API pattern.

Custom Pages in Model-Driven Apps

Custom pages embed canvas app pages within model-driven applications – enabling pixel-level control over specific areas of a model-driven form that standard form controls cannot achieve. The exam tests custom page design decisions: when a custom page is appropriate versus a PCF component versus a standard model-driven form customisation.

Domain 3: Extend Microsoft Power Platform (35-40% – Largest Domain)

Dataverse Plug-ins

Plug-ins are .NET assemblies that execute synchronously or asynchronously in response to Dataverse messages – Create, Update, Delete, Retrieve, RetrieveMultiple, and custom API messages. They run inside the Dataverse execution pipeline, giving them access to the organisation service, pre-images and post-images of the triggering record, and a shared parameter bag (input and output parameters).

Execution pipeline stages:

• Pre-Validation: Before database transaction begins – read-only context of target record as submitted.
• Pre-Operation: Inside the database transaction, before Dataverse writes – can modify the target entity’s values before they are persisted.
• Post-Operation: Inside the database transaction, after Dataverse has written – can read the final persisted values; modifications here require an additional service call.

The exam tests which stage is correct for a described requirement – modifying the record before persistence is Pre-Operation; reacting to the persisted record (triggering downstream logic based on final values) is Post-Operation.

Custom APIs extend the Dataverse message catalogue with developer-defined operations – callable like standard Dataverse API messages, supporting request/response parameter contracts, and executable by plug-in logic registered against the custom API’s message. The exam tests Custom APIs as the correct pattern for exposing reusable server-side operations to clients rather than using Action steps in cloud flows or direct SDK calls.

Dataverse Web API and Organisation Service:
The Web API is the REST endpoint for Dataverse – used from client-side code, external applications, and Power Automate HTTP actions. The Organisation Service is the .NET SDK interface – used in plug-ins and console tools running server-side. The exam tests which interface is appropriate for the described execution context.

Performance, concurrency, and bulk operations: ExecuteMultipleRequest batches multiple SDK operations into a single round trip – reducing network overhead for bulk create/update/delete scenarios. Transaction grouping controls whether operations within an ExecuteMultipleRequest share a database transaction. The exam tests when ExecuteMultipleRequest is the correct pattern and what the concurrency and rollback implications are.

Microsoft Foundry Agents with Code

Microsoft Foundry agents built with code implement custom orchestration logic, conditional execution, and external API integration that Copilot Studio’s no-code designer cannot express. The exam tests the developer’s role: implementing agent skills as code, integrating the agent with Dataverse data through Work IQ, registering the agent with an MCP server so that other Copilot agents can discover and invoke its capabilities, and integrating the agent within Power Platform workflows.

MCP servers (Model Context Protocol): MCP servers expose tools – agent-callable function definitions – that Copilot agents can discover and invoke. The exam tests MCP server creation for Power Platform: registering tool definitions (name, description, parameter schema), implementing the tool handler, and hosting the MCP server in a way that Copilot Studio agents can reach it.

Azure Functions Integration

Azure Functions extend Power Platform with scalable, event-driven server-side code for operations that exceed Dataverse plug-in constraints – long-running operations, external API integrations requiring complex authentication, and CPU-intensive transformations. The exam tests trigger types (HTTP, timer, queue, Service Bus), integration with Power Platform through custom connectors or direct HTTP calls from cloud flows, and data transformation between external formats and Dataverse-compatible structures.

Cloud Flows, Workflows, and AI Agents in Automation

The exam tests advanced Power Automate expression authoring – complex dynamic content expressions using the expression language functions (if(), coalesce(), concat(), formatDateTime(), first(), items(), body(), triggerOutputs()), child flow patterns for reusable automation modules, and error handling with scope actions and configure-run-after settings.

Domain 4: Develop Integrations (10-15%)

Custom connectors expose external APIs to Power Platform as reusable, authenticated connection types – making an external API callable from canvas apps, cloud flows, and Copilot agents without requiring users to manage authentication directly. The exam tests connector definition (OpenAPI descriptor, authentication type selection – API key, OAuth 2.0, basic), connector policies (response transformation, dynamic schema), and debugging with the connector test console.

Power Platform connectors and the Dataverse connector: The exam tests when to use the Dataverse connector (built-in, for standard Dataverse operations from cloud flows) versus a custom connector (when the target system has no existing Power Platform connector) versus a virtual table provider (when external data must appear inside Dataverse as queryable rows).

5 Study Tips for Microsoft AB-400

• Study the Dataverse plug-in execution pipeline (Pre-Validation, Pre-Operation, Post-Operation) as a decision framework – know which stage is correct for each described requirement, not just what each stage means.
• Study Microsoft Foundry agent building and MCP server tool registration as new exam content not covered by any PL-400 study material – this is the highest-risk gap for candidates transitioning from PL-400 preparation.
• Study PCF component lifecycle methods and the context object at the method signature level – know which context property provides what capability (Web API access, formatting, device features).
• Study Power Apps code apps as a distinct developer deliverable – different from canvas apps, built with React and the Power Apps CLI, with their own deployment workflow.
• Practice with Cert Empire’s AB-400 exam questions covering all four domains at October 2026 exam depth – including the new Foundry agent and MCP server skills that distinguish AB-400 from PL-400.

Best Study Resources

• Cert Empire AB-400 exam questions PDF and practice simulator (October 2026 edition).
• Microsoft official AB-400 exam page with skills outline (learn.microsoft.com/en-us/credentials/certifications/exams/ab-400/).
• Microsoft Learn: AB-400T00-A course – Extend Microsoft Power Platform Solutions with Code and AI.
• Microsoft Power Platform developer documentation (learn.microsoft.com/en-us/power-platform).
• Microsoft Dataverse documentation – plug-in development, custom API, and PCF guides (learn.microsoft.com/en-us/power-apps/developer/component-framework).

Why Candidates Choose Cert Empire for Microsoft AB-400 Preparation

Free Practice Tests

Sample our AB-400 questions before purchasing. Test your plug-in pipeline knowledge, PCF component lifecycle understanding, and Foundry agent MCP concepts before committing to the full question bank.

Regular Updates

AB-400 launched October 16, 2026, and Microsoft updates its skills outline as Power Platform evolves. Our question bank is continuously reviewed against the current official skills outline to ensure every question reflects active exam content.

Free Exam Guides

Every purchase includes our free AB-400 exam guide covering all four domain weights, the PL-400 to AB-400 content changes, the new Foundry agent and MCP server skills, and a study plan prioritising the Extend Microsoft Power Platform domain as the largest at 35-40%.

PDF Exam Questions – Study Anywhere, Anytime

Download your AB-400 questions instantly after purchase. Study on any device or print the PDF for offline sessions. No login required after download, no expiry on the file.

24/7 Chat Support

Available at any hour for questions about your materials, your order, or specific AB-400 technical concepts – including plug-in execution pipeline stages, PCF context object properties, and MCP server tool registration.

3 Months of Unlimited Access

Three full months of unlimited access to the AB-400 question bank and simulator. Revisit plug-in and custom API questions, PCF lifecycle scenarios, code app deployment questions, and agent integration scenarios as many times as needed.

Official Vendor Resources – Learn from the Source

Every solution in our AB-400 question bank links directly to the relevant official Microsoft Learn documentation – the Power Platform developer docs, the PCF component framework reference, the Dataverse plug-in developer guide, or the Foundry agent documentation – so every answer connects you to the authoritative Microsoft source.

Deep Knowledge – Every Answer, Every Option, Fully Explained

Every AB-400 question includes a complete explanation covering not just why the correct pipeline stage, context method, or agent integration approach is right, but precisely why each incorrect option fails – with a reference to the specific Microsoft Learn documentation page behind the reasoning. You build genuine Power Platform developer expertise, not answer recall.

Interactive Practice Simulator – Think Like the Exam

Our simulator presents Power Platform developer scenarios exactly as the real AB-400 exam does – describing a business requirement and testing which plug-in stage, PCF capability, code app pattern, or MCP server configuration correctly addresses it. Per-question feedback explains the full technical reasoning behind every correct and incorrect option.

Backed by a Full Money-Back Guarantee

If our AB-400 exam questions do not help you pass, you receive a full refund – no questions asked, no conditions.

FAQ’s

What is the Microsoft AB-400 certification?

AB-400 is the exam for the Microsoft Certified: Power Platform Developer Associate credential. It validates the ability to design, develop, and implement AI-powered business solutions using Power Platform – covering Dataverse plug-ins, PCF components, custom APIs, client scripting, Power Apps code apps, Microsoft Foundry agents, MCP servers, custom connectors, and solution ALM.

Does AB-400 replace PL-400?

Yes. PL-400 registration closed on October 16, 2026, and AB-400 became the sole exam for the Power Platform Developer Associate certification on the same date. The certification earned is unchanged – both exams produce the same Microsoft Certified: Power Platform Developer Associate credential.

Will my PL-400 certification still be valid after AB-400 launches?

Yes. Existing PL-400 holders keep the credential and it remains on their Microsoft Learn transcript. Renewal follows the standard Microsoft credentials renewal process through the Credentials portal.

What is new in AB-400 that was not in PL-400?

Power Apps code apps (React-based custom applications in Power Platform), Microsoft Foundry agents built with code, MCP server tool registration for agent discoverability, Copilot Studio agent integration, Python and YAML alongside JavaScript/TypeScript/C#, and AI-assisted development as an assumed part of the developer workflow.

What is an MCP server in the context of AB-400?

MCP (Model Context Protocol) servers expose named tool definitions that Copilot agents can discover and invoke. In AB-400, the exam tests building MCP servers that register custom Power Platform capabilities – making developer-built Foundry agent functions available to Copilot Studio agents through a standard discovery and invocation protocol.

Is Dataverse plug-in knowledge still important for AB-400?

Yes. The Extend Microsoft Power Platform domain remains the largest at 35-40%, and plug-ins, custom APIs, the Dataverse Web API, and the Organisation Service remain its core content. PL-400 plug-in knowledge transfers fully to AB-400.

How many questions are on the AB-400 exam?

The exam contains 40 to 60 questions and you have 120 minutes to complete it. A score of 700 out of 1000 is required to pass.

What languages are tested in AB-400?

C#, JavaScript, TypeScript, and Power Fx remain the primary languages. AB-400 adds Python and YAML to the assessed language set alongside the existing ones, reflecting their use in Foundry agent development and Power Platform automation configuration.

Related Certifications Worth Exploring

Candidates building out their Microsoft Power Platform credentials alongside AB-400 will find the Microsoft PL-200 (Power Platform Functional Consultant) exam questions page covers the functional consultant credential that works alongside the Power Platform Developer – understanding the platform’s configuration and model-driven app design from the consultant perspective. For those expanding into Microsoft’s broader developer ecosystem, the Microsoft AZ-204 (Developing Solutions for Microsoft Azure) exam questions page covers the Azure developer credential for the Azure Functions, Service Bus, and API integration skills that AB-400 requires candidates to apply within Power Platform solutions.