Free MB-820 Practice Test Real Exam Questions | Build Business Central Apps

Microsoft MB-820 Practice Test

The Microsoft MB-820 practice test helps Dynamics 365 Business Central developers check their knowledge of AL development, extensions, application objects, testing, telemetry, deployment, and integration. This exam requires more than remembering syntax. Candidates must understand how Business Central works, how extensions are structured, how data and pages are modeled, and how reliable solutions are tested and maintained. You can Discover mock exams across leading vendors to evaluate your current readiness and identify which Business Central development topics require more study. Used correctly, practice questions turn mistakes into focused coding and troubleshooting exercises.

Microsoft names MB-820 Microsoft Dynamics 365 Business Central Developer. The exam supports the Microsoft Certified: Dynamics 365 Business Central Developer Associate credential. It is intended for developers who design, build, test, deploy, troubleshoot, and maintain solutions that extend Business Central or connect it with other applications.

This guide explains the role of an MB-820 practice test, the official exam domains, and a practical method for improving from each assessment. The domain names and weightings follow Microsoft’s current official skills outline, listed as effective June 10, 2025. Certification content can change as Business Central and its development platform evolve, so candidates should compare their study plan with the latest official guide before taking the exam.

What Is a Microsoft MB-820 Practice Test?

A Microsoft MB-820 practice test is a study assessment based on the tasks expected from a Business Central developer. It should check whether you can understand the platform architecture, configure a development environment, create extensions, build AL objects, write maintainable AL code, test and monitor a solution, and integrate Business Central with external systems.

Good MB-820 questions are often scenario based. Instead of asking only what an AL keyword means, a question may describe a business requirement and ask which object, trigger, event, API, query, or permission approach should be used. Other scenarios may involve debugging an extension, improving performance, handling an upgrade, or exchanging JSON data through a REST service.

A practice test is most useful when treated as a diagnostic tool. A score can indicate general readiness, but a detailed review shows whether the problem is syntax, object design, platform knowledge, security, testing, integration, or question interpretation.

Effective practice can help you:

• Understand Business Central architecture and the extension model.
• Configure Visual Studio Code and AL development settings.
• Build and extend tables, pages, reports, enums, and codeunits.
• Use events, interfaces, queries, XMLports, and permission objects.
• Apply AL syntax, data types, procedures, and error handling.
• Create automated tests and analyze telemetry.
• Design APIs and call external REST services.
• Improve debugging, maintenance, performance, and upgrade readiness.

Who Should Use MB-820 Practice Questions?

MB-820 is designed for Business Central developers and technical consultants who build or maintain extensions. It is also relevant for software developers moving into the Dynamics 365 ecosystem, Business Central administrators with development responsibilities, and implementation professionals who need deeper technical knowledge.

Microsoft expects candidates to have applied knowledge of Business Central, the AL language, the development environment, and the tools used to create extensions. Candidates should understand how Business Central relates to Microsoft 365, Dynamics 365, Microsoft Power Platform, AppSource, and external services.

The role includes more than feature development. A Business Central developer may need to:

• Identify the root cause of an issue.
• Fix defects and validate the correction.
• Improve code quality and system performance.
• Keep data current during upgrades.
• Maintain extensions across platform versions.
• Use source control and CI/CD practices.
• Integrate Business Central with other business systems.

Hands-on practice is important. Candidates should be comfortable using Visual Studio Code with the AL Language extension, working with symbols and launch configurations, publishing extensions to a sandbox, debugging code, and reviewing results in Business Central.

Official Microsoft MB-820 Domains and Weightings

The official MB-820 outline contains six skill areas.

Developing with AL objects is the largest domain. However, the other areas are closely connected. A developer cannot build a dependable extension without understanding architecture, the environment, AL code, testing, telemetry, deployment, and integration.

Describe Business Central  10–15%

This domain checks whether you understand the platform before you begin writing code.

Business Central architecture

Candidates should know the main components and capabilities of Business Central. Understand the web client, service tier, database, extensions, applications, environments, and how users interact with the platform.

The official outline includes the core solution and extension approach. Modern Business Central customizations should be delivered through extensions instead of directly changing Microsoft’s base application. This approach supports updates, separates custom code, and makes maintenance more manageable.

You should also understand the update lifecycle for customizations. An extension may work in one version but require testing or adjustment when the platform or application changes. Good development practices reduce dependencies on internal implementation details and use supported events and APIs where possible.

Business Central online and on-premises environments have different management, deployment, infrastructure, update, and integration considerations. Practice questions may ask which capability or responsibility applies to each model. Avoid assuming that a task available on-premises can be performed in exactly the same way online.

Business Central applications

The base app and system app serve different purposes. The system app provides lower-level platform-related application functionality, while the base app contains core business functionality. Developers should understand dependencies and avoid duplicating standard capabilities.

Microsoft also expects candidates to understand Business Central apps and the process of bringing an app to AppSource. AppSource solutions need appropriate structure, naming, testing, documentation, validation, compatibility, and marketplace readiness. Even if you have not published an app, you should understand why AppSource extensions require stronger standards than a private customization used by one tenant.

Install, Develop, and Deploy for Business Central  10–15%

This domain covers the development environment and the extension lifecycle.

Configure the development environment

Business Central development commonly uses Visual Studio Code and the AL Language extension. Candidates should understand how to install and configure the environment, connect to a Business Central sandbox, download symbols, and manage project files.

Important configuration files include app.json, which defines extension metadata and dependencies, and launch.json, which controls connection and debugging settings. A question may present a publishing, symbol, dependency, or debugging issue and ask which configuration needs to be changed.

The outline also includes multiple AL extensions in one workspace. This is useful when a solution contains several related projects or dependencies. You should understand how project references, app IDs, versions, and dependency information affect build order and deployment.

Create, debug, and deploy extensions

Candidates should be able to create or modify an extension, publish it, attach the debugger, use breakpoints, inspect variables, and trace code execution. Debugging is not only about finding syntax errors. It helps identify incorrect business logic, unexpected trigger order, integration failures, and data problems.

Multilanguage development is another objective. User-facing labels, captions, errors, and report content should be designed so they can be translated. Avoid hard-coded display text when localization is required.

Maintaining an extension includes versioning, dependency management, compatibility testing, upgrade code, data changes, and clean deployment. Practice scenarios may ask how to preserve data when a table structure changes or how to update an extension without disrupting users.

Develop by Using AL Objects  35–40%

This is the largest MB-820 domain. Candidates should understand the purpose, structure, and interaction of common AL object types.

Tables, pages, and enums

Tables define how business data is stored. Developers should understand fields, keys, properties, field groups, validation, relationships, and table extensions. A table extension adds fields or behavior to an existing table without modifying Microsoft’s original object.

Pages present data to users. The outline includes different page types, page objects, page extensions, and Role Center pages. Choose a page type based on the user experience: a list, card, document, worksheet, Role Center, API page, or another supported pattern.

Enums provide a controlled set of values and can be extended when designed for extensibility. They are often preferable to older option-based designs because they support cleaner extension scenarios.

Practice questions may describe a requirement to add a field, display it on a page, validate its value, or add a new selectable state. Break the requirement into data, user interface, and logic components before choosing the objects.

Reports

Business Central reports include a data model, triggers, request page, and layout. Candidates should know how to create document reports, design datasets, implement layouts, use processing-only reports, and work with report triggers and functions.

The official outline also includes report substitution. An extension can replace a standard report for a specified usage. Learn when substitution is appropriate and how it differs from creating a completely separate report.

Multilanguage reporting requires captions and labels that can be translated. A report may function correctly but still provide a poor experience if text is hard coded.

XMLports

XMLports are used to import or export structured data. Candidates should understand XMLport properties, nodes, text elements, table elements, formats, field separators, and how XMLports are called from AL code.

A practice scenario may ask how to exchange a delimited file with another system, validate imported values, or export selected records. Identify the file structure and direction of data movement before configuring nodes.

Codeunits, events, and interfaces

Codeunits organize reusable business logic. Developers should know how to create and call them, expose procedures, and use triggers where appropriate.

Events are essential to the extension model. Event publishers announce that something happened; subscribers respond without changing the original object. This reduces coupling and improves upgrade compatibility. Understand business events, integration events, trigger events, and how subscriber parameters affect behaviour.

Interfaces enable multiple implementations behind a common contract. They support cleaner designs when behaviour varies by type or scenario. A question may ask which design avoids a long conditional structure and makes future extensions easier.

Installation and upgrade codeunits support tasks that must run when an extension is installed or upgraded. Use them carefully for setup, data migration, and version transitions.

Permission sets and entitlements

Developers can create or extend permission-set objects. Permission sets define access to Business Central objects and data. Candidates should understand direct and indirect permissions, permission-set extensions, inherent permissions, and troubleshooting access failures.

Do not solve every permission issue by granting broad access. Follow least privilege and determine which object or data operation is being blocked.

Queries

Query objects can join data items, apply filters, aggregate values, and improve data retrieval for reporting or processing. The official outline includes using queries instead of record variables and using query results in reports.

Practise choosing between a query, report dataset, API, or direct record processing. A query can provide efficient read-oriented access, but it is not a replacement for every data operation.

If you are working toward additional Microsoft credentials, View the complete Microsoft exam collection and choose practice material that matches your development or functional-consulting path.

Develop by Using AL  15–20%

This domain focuses on the AL language, user experience, onboarding, development standards, and business-data patterns.

User interface and onboarding

Candidates should understand profiles, views, assisted setup, teaching tips, in-app tours, user assistance, and onboarding checklists. A successful extension is not only technically correct; users must be able to understand and adopt it.

Profiles can tailor the experience for a role. Views can provide filtered or organized page presentations. Assisted setup helps users complete configuration. Teaching tips and tours explain features inside the interface. Use the lightest onboarding method that meets the user’s needs.

Development standards

The official guide includes the Business Central data process model, functional table types, document standards, master-data standards, and design patterns.

Business Central has established patterns for documents, journals, posting, master data, setup, and ledger entries. A custom feature should follow these patterns when it behaves like standard functionality. Reusing familiar patterns makes the solution easier to understand, test, and maintain.

Core AL programming

Candidates need practical knowledge of procedures, variables, data types, expressions, built-in functions, statements, file handling, data manipulation, access modifiers, and error management.

Access modifiers control whether code is available within the object, module, or outside the extension. Choose the narrowest access that supports the design. Exposing unnecessary procedures increases coupling.

Error handling should provide clear feedback and protect data consistency. Understand validation errors, runtime errors, transactions, and when to stop processing. Avoid hiding an important failure simply to let the process continue.

AL record operations are central to Business Central development. Practise filtering, finding, reading, inserting, modifying, deleting, validating, and iterating records. Understand when validation triggers should run and why directly assigning a value can behave differently from calling Validate.

Convert Practice-Test Mistakes Into Coding Tasks

After a mock assessment, organize each incorrect answer by domain and error type.

Useful categories include:

• Platform gap: You did not understand Business Central architecture or app structure.
• Object-selection gap: You selected the wrong AL object for the requirement.
• Language gap: You misunderstood AL syntax, data types, procedures, or record operations.
• Lifecycle gap: You missed a deployment, update, versioning, or upgrade requirement.
• Testing gap: You knew the feature but not how to verify it.
• Integration gap: You confused REST calls, APIs, OData actions, or JSON handling.
• Question-reading error: You missed a condition such as extensibility, performance, localization, or least privilege.

For each error, create a small development task. Build a page extension, write an event subscriber, add a permission set, design a query, create a test codeunit, or call a sample REST endpoint. Short, focused coding exercises build stronger memory than rereading the same explanation.

Make every practice session count by combining structured assessments with Microsoft Learn, official documentation, Visual Studio Code exercises, and a simple mistake log.

Work With Development Tools  10–15%

This domain covers testing and telemetry, two areas that make extensions reliable in production.

Automated testing

Candidates should understand standard Business Central tests, the Test Toolkit, test codeunits, and test procedures. Automated tests help verify that changes work as expected and reduce the risk of breaking existing behaviour.

A useful test should arrange data, perform an action, and verify the result. Tests should be repeatable and independent. Avoid relying on data that happens to exist in one environment.

Test libraries and handler functions can help simulate user interactions or reuse setup logic. Practise identifying what should be tested: successful processing, validation failures, permissions, edge cases, upgrade behaviour, and integrations.

Telemetry

Telemetry helps developers understand how an extension behaves after deployment. The official outline includes configuring telemetry, monitoring and analyzing it, and creating custom telemetry signals.

Useful telemetry can show errors, long-running operations, feature usage, dependency failures, or unexpected patterns. Custom signals should have a clear purpose and should not expose sensitive information.

Testing answers the question “Does the code behave correctly under known conditions?” Telemetry helps answer “What is happening in real environments?” Strong development uses both.

Integrate Business Central With Other Applications  10–15%

This domain checks whether you can exchange information with external services and expose Business Central functionality through supported interfaces.

Calling REST services

Candidates should understand AL HTTP classes, including clients, requests, responses, headers, and content. You should be able to send and receive data, inspect status codes, and handle failures.

JSON is widely used in REST integrations. Practise creating, reading, and navigating JSON objects, arrays, tokens, and values. A successful request is not enough; code should validate the response and handle missing or unexpected data.

Security is also important. Credentials, tokens, keys, and endpoints should be managed safely. Do not hard-code secrets in extension code. Consider timeouts, retries, rate limits, logging, and idempotency when designing an integration.

APIs and OData actions

Business Central APIs expose business data through supported endpoints. Candidates should understand how to create and work with API pages and how versioning, entity names, keys, fields, and data access affect consumers.

OData bound actions operate on a specific entity, while unbound actions are not tied to one record. Questions may ask which action type suits a requirement.

The official outline also includes Read Scale-Out, which can improve read performance by directing eligible read-only workloads to a replica. Understand that it supports reading and is not appropriate for operations that must immediately write or depend on the latest primary-database state.

How to Use MB-820 Mock Assessments Effectively

Use practice in stages:

1. Take a short mixed baseline. Answer without searching documentation.
2. Map each mistake to a domain. This reveals whether the gap is broad or concentrated.
3. Explain the requirement. State the object, behaviour, data, security, or integration need.
4. Compare the nearest choices. Explain why the alternatives do not fit.
5. Check official documentation. Confirm syntax, properties, triggers, limitations, and recommended patterns.
6. Build a small extension. Reproduce the concept in a sandbox.
7. Add a test or telemetry signal. Verify the behaviour and make it observable.
8. Retest with a new scenario. Fresh wording checks actual understanding.

Watch for clues such as “extend without modifying,” “multilanguage,” “upgrade,” “least privilege,” “aggregate,” “external REST service,” “automated test,” “AppSource,” or “read-only performance.” These usually identify the main objective being tested.

What You Get When You Prepare With Us

Our MB-820 preparation structure helps learners connect official objectives with realistic Business Central development work.

• Current domain organization: Practice follows Microsoft’s six official skill areas.
• Scenario-based learning: Questions focus on development decisions rather than isolated definitions.
• Clear explanations: Answer reviews show why an object, method, or pattern fits the requirement.
• Weak-area tracking: Results identify gaps in AL objects, language, deployment, testing, telemetry, or integration.
• Hands-on direction: Missed questions can be converted into small Visual Studio Code tasks.
• Flexible study: Short topic sessions support regular revision, while mixed assessments check overall readiness.
• Maintenance awareness: Practice includes upgrade, security, testing, and performance considerations.

Practice questions should supplement Microsoft Learn, AL documentation, Business Central documentation, and hands-on development. They should not be presented as live exam content or as a guarantee of passing.

Common MB-820 Preparation Mistakes

Studying AL syntax without learning Business Central patterns

Correct syntax can still produce a poor Business Central extension. Learn standard document, posting, master-data, setup, and ledger patterns.

Modifying instead of extending

The extension model is central to Business Central. Prefer supported extension objects, events, interfaces, and APIs over tightly coupled customizations.

Ignoring upgrades

Schema changes, dependencies, data movement, and platform updates affect long-term maintenance. Include upgrade thinking from the beginning.

Skipping automated tests

Manual checking is not enough for a maintained extension. Practise test codeunits, assertions, handlers, and repeatable setup.

Treating telemetry as optional

Production issues are difficult to diagnose without useful signals. Learn how standard and custom telemetry support troubleshooting and performance work.

Memorizing the same practice set

A high score based on remembered wording does not prove development ability. Use new scenarios and implement the concept in a sandbox.

A Four-Week MB-820 Study Framework

Week 1: Architecture and environment

Review Business Central architecture, online versus on-premises differences, base and system apps, extensions, AppSource, Visual Studio Code, AL configuration files, symbols, workspaces, debugging, publishing, localization, and extension maintenance.

Week 2: AL objects

Build and extend tables, pages, enums, reports, XMLports, codeunits, permission sets, and queries. Create one small extension that connects several objects into a complete feature.

Week 3: AL language and platform patterns

Practise procedures, variables, data types, expressions, record operations, files, errors, access modifiers, events, interfaces, UI assistance, onboarding, and Business Central development standards.

Week 4: Testing, telemetry, and integration

Create automated tests, run the Test Toolkit, review telemetry, add custom signals, call an external REST service, process JSON, create an API, and review OData actions. Finish with fresh mixed assessments.

Frequently Asked Questions

What does Microsoft MB-820 cover?

MB-820 covers Business Central architecture, development environments, extensions, AL objects, AL programming, testing, telemetry, REST integrations, APIs, and OData actions.

Which MB-820 domain has the highest weighting?

Develop by using AL objects is the largest domain at 35–40%.

Do I need practical AL experience?

Yes. Candidates should be comfortable creating and debugging extensions in Visual Studio Code and working with common AL objects and language features.

Does MB-820 include integration topics?

Yes. The official outline includes calling REST services, reading and creating JSON, implementing APIs, using bound and unbound OData actions, and Read Scale-Out.

Are testing and telemetry included?

Yes. Candidates should understand the Business Central Test Toolkit, test codeunits and procedures, standard tests, telemetry configuration, analysis, and custom signals.

How should I review a wrong practice answer?

Identify the domain and the missed requirement, check Microsoft documentation, then build a small extension or code sample that demonstrates the correct approach.

Are practice tests enough for MB-820?

No. Combine mock assessments with Microsoft Learn, AL and Business Central documentation, source-control practice, and hands-on sandbox development.