Microsoft AB-400: Extending Microsoft Power Platform Solutions with Code and AI

Last checked October 22, 2026 against the official Microsoft exam page.

1. Question 1Extend the platform

   A plug-in must run only once for each record update, even when the same update triggers the plug-in through another step. Which technique helps prevent duplicate execution?

   1. AChecking the execution context and a guard value such as a depth or correlation check before processing
   2. BDisabling the Organization service for the plug-in assembly, which breaks the record update pipeline in production
   3. CRegistering the plug-in twice on the same message with identical filtering attributes and different execution stages
   4. DRunning the plug-in in a loop until it succeeds and retrying each failed attempt without a limit
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   Correct answer: A

   Guards based on execution context prevent duplicate or recursive processing. Double registration duplicates work, loops amplify problems, and disabling the service breaks plug-ins.

2. Question 2Extend the user experience

   A model-driven app form needs to show or hide a field based on the value of another field without a server round trip. Which approach is recommended?

   1. AA plug-in that runs on every read and returns field visibility from the server
   2. BA scheduled batch that updates the form nightly and writes results to the record
   3. CClient scripting using the Client API on the form's OnChange event
   4. DA flow triggered by a button in the browser after each click
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   Correct answer: C

   Client scripting on OnChange reacts immediately in the browser without a server round trip. Plug-ins on read, browser-triggered flows and nightly batches do not provide immediate form behavior.

3. Question 3Build Microsoft Power Platform solutions

   A team must decide whether a requirement can be met with out-of-the-box functionality or needs custom code. Which factor should be evaluated first?

   1. AThe color of the app's logo in the header, since branding choices decide whether custom code is needed
   2. BThe name of the solution publisher and its prefix, since naming conventions do not affect the design
   3. CWhether a built-in feature such as a model-driven app view, business rule, or flow already meets the requirement
   4. DThe number of developers available for the project and their experience with C#, since staffing levels determine the build approach
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   Correct answer: C

   Evaluating whether built-in features meet the requirement avoids unnecessary custom code. Logo colors, team size and publisher names do not determine the design.

4. Question 4Extend the platform

   A Dataverse custom API should accept a request with input parameters and return a result that other apps can use. Which configuration is required?

   1. AA flow that runs every minute with no outputs and writes logs to a SharePoint list
   2. BA custom API message with defined request and response parameters bound to a plug-in
   3. CA web resource that returns static HTML and renders a page for each caller
   4. DA canvas app that exports a CSV file from a Dataverse table when pressed
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   Correct answer: B

   A custom API with defined parameters and a bound plug-in gives a reusable, contract-based server operation. Static HTML, CSV exports and minute-level flows do not form an API contract.

5. Question 5Extend the user experience

   A developer wants a command bar button that is visible only for records in an approved status. Which configuration supports this?

   1. AA ribbon button with a display rule based on the status column value
   2. BA button that remains visible and hides itself with CSS through a custom stylesheet
   3. CA canvas app button embedded in a model-driven form with an OnSelect formula
   4. DA flow that deletes the button when the status changes and rebuilds the ribbon XML
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   Correct answer: A

   Display rules on ribbon buttons control visibility based on record values. CSS-only hiding is cosmetic, canvas buttons do not appear in the model-driven command bar, and flows do not manage button display.