Dynamics 365 Plug-in Best Practices

Microsoft Dynamics 365 is a powerful platform for building business applications, and one of its most extensible features is the ability to write custom plug-ins. Plug-ins are pieces of .NET code that execute in response to events within the Dataverse platform—such as record creation, updates, deletes, and more.

When developed and deployed correctly, plug-ins can add rich business logic and automation to your Dynamics 365 apps. However, poor plug-in design can lead to performance issues, maintenance headaches, and even data integrity problems. That’s why following best practices is crucial.

This article walks you through essential plug-in development best practices, from architecture to coding, debugging, and deployment.

What Are Plug-ins in Dynamics 365?

A plug-in is a custom business logic handler written in C# (or VB.NET) that executes in response to specific events triggered by the Dataverse event pipeline. These events can be:

Create
Update
Delete
Assign
SetState / SetStateDynamicEntity
Associate / Disassociate

Plug-ins run synchronously or asynchronously, depending on their registration, and can be configured to run in different pipeline stages (PreValidation, PreOperation, PostOperation).

Why Use Plug-ins?

Plug-ins allow developers to:

Implement complex business rules
Integrate external systems
Enforce validations that aren’t possible via business rules or workflows
Modify related records during transactions
Perform audit or logging operations

Plug-in Development Best Practices

1. Design for Minimalism

Avoid overcomplicating plug-ins. They should perform only the logic necessary to complete a task. Keep code clean and focused.

📌 Each plug-in should have a single responsibility.

2. Use Early Exit Conditions

Check for essential conditions early and exit if unnecessary to continue. This improves performance and avoids unintended executions.

Example:

if (!context.InputParameters.Contains("Target") || !(context.InputParameters["Target"] is Entity))
    return;

3. Avoid Hardcoded Values

Do not hardcode:

Record IDs
Entity names
Field names

Use nameof() where possible or store configurable values in Environment Variables or Custom Settings.

4. Use Tracing for Debugging

Always inject ITracingService and log meaningful messages. It’s critical for diagnosing errors in production, especially with sandboxed plug-ins.

Example:

tracingService.Trace("Plug-in started for entity: {0}", entity.LogicalName);

5. Respect the Execution Context

Always check the MessageName, Stage, Mode, and Depth before executing business logic. This avoids recursion and ensures your code runs only under intended conditions.

if (context.Depth > 1)
    return; // Prevent infinite loops

6. Use Late-Bound vs Early-Bound Wisely

Late-bound (e.g., Entity["fieldname"]) provides flexibility across entities but is error-prone and less readable.
Early-bound (e.g., account.name) is safer and easier to maintain but requires entity classes to be regenerated when schema changes.

✅ Use early-bound models in large or team-based projects for clarity and type safety.

7. Limit Use of Service Calls

Avoid making unnecessary calls to IOrganizationService. Minimize the number of Create, Update, or Retrieve calls by:

Using Target data already provided
Avoiding redundant fetches

Also, avoid looping over records with separate calls—use RetrieveMultiple when needed.

8. Avoid Synchronous Plug-ins Unless Required

Synchronous plug-ins impact the UI and overall system responsiveness. Prefer asynchronous plug-ins for tasks like:

External API calls
Heavy data processing
Integrations

9. Handle Exceptions Gracefully

Catch exceptions and log meaningful error messages. Never throw raw exceptions. Instead, use:

throw new InvalidPluginExecutionException("A validation error occurred: [details]");

This provides a cleaner user experience.

10. Test in Isolation

Write unit tests where possible using mocking frameworks like:

Moq
FakeXrmEasy
XrmUnitTest

These help catch logic errors before deploying to environments.

Plug-in Structure Best Practices

Organize your plug-in solution like this:

/Plugins
  |-- BasePlugin.cs
  |-- AccountCreatePlugin.cs
  |-- ContactUpdatePlugin.cs
/Models
/Services
/Helpers

Separate logic into service classes, keeping your plug-in entry class lean.

Example Pattern:

public class AccountCreatePlugin : PluginBase
{
    protected override void ExecutePluginLogic(LocalPluginContext localContext)
    {
        var accountService = new AccountService(localContext);
        accountService.HandleAccountCreation();
    }
}

Security Considerations

Run plug-ins in the least privileged security context.
Avoid impersonating system admins unless explicitly needed.
Secure all data used in external API calls or logging.

Deployment Best Practices

Use a Solution Strategy

Always register plug-ins through a solution.
Maintain plug-ins under source control (e.g., Git).
Follow ALM practices using Azure DevOps, GitHub Actions, or Power Platform Pipelines.

Register Plug-ins with Plugin Registration Tool (PRT) or DevOps

Use:

Plugin Registration Tool for development
Solution deployment with Plug-in Assemblies for CI/CD pipelines

Choosing Between Plug-ins and Alternatives

Task	Use Plug-in?	Alternatives
Complex record validation	✅ Yes	Business rules (if simple)
Real-time integration	✅ Yes (if sync)	Power Automate (async)
Updating related records	✅ Yes	Workflows (limited)
External service call	❌ Prefer async	Power Automate / Azure Function
UI logic	❌	JavaScript

📌 Choose the right tool for the job. Don’t overuse plug-ins for every scenario.

Tips for Performance and Maintainability

Use batch operations when possible.
Avoid deep nesting in logic.
Use Dependency Injection (DI) if building with frameworks like XrmUnitTest.
Keep assemblies small and modular.
Use versioning in assemblies for better tracking.

Real-World Example: Plug-in for Duplicate Email Check

public class ContactCreatePlugin : IPlugin
{
    public void Execute(IServiceProvider serviceProvider)
    {
        var context = (IPluginExecutionContext)serviceProvider.GetService(typeof(IPluginExecutionContext));
        var serviceFactory = (IOrganizationServiceFactory)serviceProvider.GetService(typeof(IOrganizationServiceFactory));
        var service = serviceFactory.CreateOrganizationService(context.UserId);
        var tracing = (ITracingService)serviceProvider.GetService(typeof(ITracingService));

        try
        {
            if (!(context.InputParameters["Target"] is Entity target) || target.LogicalName != "contact") return;

            if (target.Contains("emailaddress1"))
            {
                string email = target["emailaddress1"].ToString();
                var query = new QueryExpression("contact")
                {
                    ColumnSet = new ColumnSet("contactid"),
                    Criteria = { Conditions = { new ConditionExpression("emailaddress1", ConditionOperator.Equal, email) } }
                };

                var results = service.RetrieveMultiple(query);
                if (results.Entities.Count > 0)
                {
                    throw new InvalidPluginExecutionException($"A contact with the email '{email}' already exists.");
                }
            }
        }
        catch (Exception ex)
        {
            tracing.Trace("ContactCreatePlugin: {0}", ex.ToString());
            throw new InvalidPluginExecutionException("An error occurred in the ContactCreatePlugin.", ex);
        }
    }
}