Custom APIs & Business Events

Creating your own Dataverse operations

Simple explanation

Think of custom APIs as adding new buttons to a universal remote control.

Dataverse comes with built-in operations: Create, Update, Delete, Retrieve. These are like the standard buttons on a TV remote — power, volume, channel. But what if you need a “Calculate Shipping” button or a “Validate Insurance” button? You create a custom API.

A custom API is a new operation you define on Dataverse. You name it, declare what inputs it accepts and what outputs it returns, and wire it to a plug-in that does the actual work. Then anyone — apps, flows, external systems — can call your API just like they call the built-in Create or Update.

Business events are the flip side: instead of something calling IN to Dataverse, business events let Dataverse push events OUT to other systems when something important happens.

Custom API anatomy

A custom API consists of three parts:

The API definition — name, binding type, request parameters, response properties
Request parameters — typed inputs the caller sends
Response properties — typed outputs the API returns

Creating a custom API

Setting	What It Controls	Example
Unique Name	API identifier (used in SDK/Web API calls)	`nova_CalculateShipping`
Display Name	Human-readable name	`Calculate Shipping Cost`
Binding Type	Global (no entity) or Entity-bound	Global — not tied to a specific table
Is Function	GET (read-only) or POST (action)	No (POST — it performs a calculation)
Is Private	Hidden from external callers	No — ISVs and external systems can call it
Allowed Custom Processing Step Type	Sync only, Async only, or Both	Sync only (caller waits for result)
Plugin Type	The plug-in that implements the logic	`NovaSoft.ShippingCalculator`

Defining parameters and response

Request Parameters:
  - Weight (Decimal, required)
  - DestinationCode (String, required)
  - Priority (Integer, optional)

Response Properties:
  - Cost (Decimal)
  - EstimatedDays (Integer)
  - TrackingPrefix (String)

Implementing the plug-in

public class CalculateShipping : IPlugin
{
    public void Execute(IServiceProvider serviceProvider)
    {
        var context = (IPluginExecutionContext)
            serviceProvider.GetService(typeof(IPluginExecutionContext));
        
        // Read custom API request parameters
        decimal weight = (decimal)context.InputParameters["Weight"];
        string destination = (string)context.InputParameters["DestinationCode"];
        int priority = context.InputParameters.Contains("Priority") 
            ? (int)context.InputParameters["Priority"] : 1;
        
        // Business logic
        decimal baseCost = weight * 2.5m;
        decimal priorityMultiplier = priority == 1 ? 1.0m : priority == 2 ? 1.5m : 2.0m;
        decimal cost = baseCost * priorityMultiplier;
        int estimatedDays = priority == 3 ? 1 : priority == 2 ? 3 : 5;
        
        // Set custom API response properties
        context.OutputParameters["Cost"] = cost;
        context.OutputParameters["EstimatedDays"] = estimatedDays;
        context.OutputParameters["TrackingPrefix"] = "TRK-" + destination;
    }
}

Calling the custom API

From the Web API (any HTTP client):

POST /api/data/v9.2/nova_CalculateShipping
Content-Type: application/json

{
    "Weight": 25.5,
    "DestinationCode": "NZ-AKL",
    "Priority": 2
}

From a cloud flow: Use the “Perform an unbound action” Dataverse connector action.

From C# SDK: service.Execute(new OrganizationRequest("nova_CalculateShipping") { ... });

Business events

Business events let Dataverse broadcast events to external systems when specific operations occur.

How they work

Define a business event on a table (e.g., “Order Approved” on the Order table)
Configure the trigger — which message and stage fires the event
Subscribe external systems — Azure Service Bus, Event Hub, webhooks
Events publish automatically when the trigger condition is met

Business events vs plug-ins

Business events push outward; plug-ins process internally
Feature	Business Event	Plug-in
Purpose	Notify external systems	Execute custom logic in Dataverse
Direction	Outbound (Dataverse → external)	Internal (within Dataverse pipeline)
Custom code	No code needed for basic events	C# code required
Subscribers	Service Bus, Event Hub, webhooks	N/A — plug-in runs internally
Solution-aware	Yes	Yes
Use when	External systems need to react to Dataverse changes	You need to validate, enrich, or process data within Dataverse

Question

What is a custom API in Dataverse?

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Answer

A custom API defines a new message (endpoint) on Dataverse with typed request parameters and response properties. It is backed by a C# plug-in and can be called from apps, flows, Web API, or SDK. It is the modern replacement for custom process actions.

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Question

How do you read request parameters in a custom API plug-in?

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Answer

Through context.InputParameters: decimal weight = (decimal)context.InputParameters['Weight']. Set response values through context.OutputParameters: context.OutputParameters['Cost'] = calculatedCost. The parameter names must match what you defined in the custom API configuration.

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Question

What is a Dataverse business event?

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Answer

A business event broadcasts an event to external subscribers (Service Bus, Event Hub, webhooks) when a specific Dataverse operation occurs. No custom C# code is needed — you define the event trigger and subscribers. External systems react to the published event.

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Knowledge Check

Elena needs to create an operation that accepts an employee ID and returns their accrued leave balance. The operation must be callable from canvas apps, cloud flows, and an external HR system via REST API. What should she build?

Next up: Custom Connectors: OpenAPI & Authentication — wrapping external APIs for Power Platform consumption.