PL-400 · Sample questions

PL-400 sample questions with answers and explanations

9 real questions from the CertifyDeck PL-400 bank, spread across the domains of the official Microsoft Power Platform Developer skills outline, with the correct answer and a full explanation of why the other options are wrong. They are original questions written from the public syllabus, not exam dumps, and they are the same style you will find in the practice tests and mock exams.

1. Question 1Domain: Create a technical designMedium

   A team is building five canvas apps that all need the same branded header with a logo, navigation buttons, and consistent styling that non-technical makers should be able to drop onto a screen without writing code. Which approach should the architect recommend?

   • B.Create a canvas component packaged in a component library and share it across apps
   • A.Build a Power Apps component framework (PCF) code component in TypeScript
   • C.Duplicate the header controls manually on each app screen
   • D.Implement the header as injected client-side JavaScript
   Show answer and explanation

   Correct answer: B. Create a canvas component packaged in a component library and share it across apps

   Explanation

   Canvas components in a component library are the no-code, reusable building block makers can insert directly. PCF targets more complex custom controls typically built by developers, and duplication or injected script is not maintainable.

   Official references

   • Canvas component libraries
   • Official PL-400 study guide
2. Question 2Domain: Implement Power Apps improvementsMedium

   A canvas app must show the running total of an order's line items only while the user is editing the order, without saving to Dataverse until the user submits. Which Power Fx approach best fits this requirement?

   • B.Write a Dataverse plug-in to calculate the total on each keystroke
   • C.Call a cloud flow on every field change to recalculate the total
   • D.Store the running total directly in a hidden Dataverse field on every change
   • A.Use a local collection to hold line items and Sum() over it for the running total
   Show answer and explanation

   Correct answer: A. Use a local collection to hold line items and Sum() over it for the running total

   Explanation

   A local collection plus Sum() gives an instant, client-side running total with no server round-trip or premature persistence, matching the "not saved until submit" requirement.

   Official references

   • Power Fx overview
   • Official PL-400 study guide
3. Question 3Domain: Implement Power Apps improvementsMedium

   Contoso University needs a component to expose a property that returns a table of selected items so the host app can act on the whole selection at once. Which custom property data type should the maker choose?

   • A.Table
   • B.Record
   • C.Boolean
   • D.Screen
   Show answer and explanation

   Correct answer: A. Table

   Explanation

   Custom properties in canvas app components support a Table data type specifically for exposing collections of records, which fits a multi-selection scenario where the host app needs the full list of selected items. Record only represents a single row of data, not multiple selections. Boolean only holds true/false. Screen is not a valid custom property data type.

   Official references

   • Custom properties for canvas app components
   • Official PL-400 study guide
4. Question 4Domain: Develop integrationsEasy

   Which of the following best describes a webhook service endpoint in the context of Dataverse plug-in registration?

   • B.A SQL Server stored procedure triggered on row insert
   • C.A SharePoint document library event receiver
   • A.An HTTP endpoint that receives an HTTP POST request when a registered Dataverse event occurs
   • D.An Azure Active Directory conditional access policy
   Show answer and explanation

   Correct answer: A. An HTTP endpoint that receives an HTTP POST request when a registered Dataverse event occurs

   Explanation

   A webhook endpoint is an HTTP(S) URL that Dataverse calls with an HTTP POST containing the execution context whenever a registered plug-in step fires. The other options are unrelated integration mechanisms not used as Dataverse service endpoints.

   Official references

   • Use webhooks with Dataverse
   • Official PL-400 study guide
5. Question 5Domain: Extend the platformMedium

   At Blue Yonder Airlines, every flight booking add-on must have its price recalculated with a 10% loyalty-member discount at the exact moment the add-on record is created, using the loyalty tier already stored on the parent booking. The team wants this rule to run for every client (web, mobile, and integrations) and be impossible to bypass. Where should the core discount calculation logic be implemented?

   • A.In client-side JavaScript form scripts on the add-on form, since it runs immediately when the user enters data
   • B.In a Power Automate flow triggered on a schedule that periodically corrects prices
   • C.In a plug-in registered on the Create message of the add-on table, so it always runs server-side regardless of client
   • D.In a canvas app formula that recalculates price before submitting the form
   Show answer and explanation

   Correct answer: C. In a plug-in registered on the Create message of the add-on table, so it always runs server-side regardless of client

   Explanation

   Core business logic that must be enforced consistently and cannot be bypassed belongs on the server, and a plug-in registered on the Create message of the relevant table guarantees the logic runs for every client and integration path, including the Web API directly. Client-side form scripts and canvas app formulas only run for the specific client that hosts them and can be bypassed by other clients or direct API calls. A scheduled flow introduces a delay and does not calculate the value at creation time, which fails the "exact moment" requirement.

   Official references

   • Write a plug-in
   • Best practices for developing plug-ins
   • Official PL-400 study guide
6. Question 6Domain: Extend the user experienceMedium

   A form script must retrieve related contact records for the currently loaded account without triggering a full page navigation, then render a summary on the form. Which approach should it use?

   • B.Xrm.Navigation.openForm on each contact
   • C.A synchronous plug-in triggered by form load
   • A.Xrm.WebApi.retrieveMultipleRecords() to query contacts filtered by the account, then render the results client-side
   • D.Refresh the whole page to force a subgrid to appear
   Show answer and explanation

   Correct answer: A. Xrm.WebApi.retrieveMultipleRecords() to query contacts filtered by the account, then render the results client-side

   Explanation

   Xrm.WebApi.retrieveMultipleRecords() is the client-side, asynchronous way to query related data via the Web API without navigating away or reloading the page. openForm navigates away from the current record, which the requirement explicitly rules out; a plug-in runs server-side and can't render anything on the form; forcing a full page refresh defeats the purpose of an inline summary.

   Official references

   • Xrm.WebApi
   • Official PL-400 study guide
7. Question 7Domain: Extend the user experienceMedium

   A developer at Fabrikam Logistics writes an OnChange handler for the "shippingmethod" option set field on the Order form. The handler must dynamically show or hide the "expeditedcost" field depending on the selected option. Which Client API call correctly hides the field?

   • B.formContext.getAttribute("expeditedcost").setRequiredLevel("none")
   • C.formContext.ui.tabs.get("general").setVisible(false)
   • D.formContext.getAttribute("expeditedcost").setSubmitMode("never")
   • A.formContext.getControl("expeditedcost").setVisible(false)
   Show answer and explanation

   Correct answer: A. formContext.getControl("expeditedcost").setVisible(false)

   Explanation

   Visibility of a field control is toggled with getControl(name).setVisible(boolean). setRequiredLevel changes the business requirement level, not visibility. Hiding the whole tab (option C) would hide unrelated fields too. setSubmitMode controls whether the value is saved, not whether it is displayed.

   Official references

   • Control.setVisible (Client API reference)
   • Official PL-400 study guide
8. Question 8Domain: Build Power Platform solutionsMedium

   A solution's cloud flow needs to call a different API endpoint URL in development, test, and production, without editing the flow definition after each deployment. What should the architect use?

   • A.Hardcode the URL in the flow's HTTP action
   • C.Store the URL in a SharePoint list
   • D.Have users enter the URL manually each run
   • B.Create an environment variable for the URL with a different current value per environment
   Show answer and explanation

   Correct answer: B. Create an environment variable for the URL with a different current value per environment

   Explanation

   Environment variables are solution-aware values that differ per environment without modifying the underlying flow definition after deployment — exactly this scenario. Hardcoding the URL means editing the flow after every deployment; a SharePoint list adds an external dependency with no solution-layer environment binding; manual entry isn't reliable or automatable.

   Official references

   • Environment variables
   • Official PL-400 study guide
9. Question 9Domain: Build Power Platform solutionsEasy

   A maker at Thornbury Insurance tries to delete a choice column from a table, but Dataverse blocks the deletion with a dependency error. What is the most likely reason?

   • A.The column is referenced by another component, such as a form, view, or business rule, that must be removed or updated first
   • B.Choice columns can never be deleted once a single record has been saved
   • C.Dataverse blocks all column deletions in sandbox environments
   • D.Only System Administrators can delete columns, and this is unrelated to dependencies
   Show answer and explanation

   Correct answer: A. The column is referenced by another component, such as a form, view, or business rule, that must be removed or updated first

   Explanation

   Dataverse tracks component dependencies, and it will block deletion of a column, table, or other component if another component (a form, view, chart, business rule, or similar) still references it. The dependent components must be updated or removed first before the deletion is allowed.

   Official references

   • Remove a dependent component
   • Official PL-400 study guide