Custom Connectors in the Power Platform: integrate any REST API

Custom Connectors wrap calls to external APIs in a format reusable across Power Apps and Power Automate. Instead of using the generic HTTP connector in every flow, you create a shared connector with well-defined authentication, types and actions.

Create from OpenAPI/Swagger

// make.powerapps.com → Data → Custom Connectors → New → Import OpenAPI file
// Or: import the URL of the API's Swagger endpoint

// Minimal OpenAPI example:
openapi: "3.0.0"
info:
  title: BConcepts Projects API
  version: "1.0"
servers:
  - url: https://api.bconcepts.pt/v1
paths:
  /projects:
    get:
      summary: List projects
      operationId: ListProjects
      parameters:
        - name: status
          in: query
          schema: { type: string }
      responses:
        "200":
          description: List of projects
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: "#/components/schemas/Project"

Configure OAuth2 authentication

// In the Custom Connector → Security → Authentication type: OAuth 2.0
Provider: Azure Active Directory
Client ID: (App Registration client_id)
Client Secret: (stored in the Custom Connector — not visible to the user)
Resource URL: api://your-api-app-id
Redirect URL: https://global.consent.azure-apim.net/redirect

Actions and triggers

// Action: create project
POST /projects
Request body:
  { "name": string, "customer_id": integer, "budget": number }
Response: { "id": integer, "name": string, "status": string }

// Trigger (webhook): notified when a project changes status
// Configure the webhook on create, return the webhook id in the response
// Power Automate unsubscribes automatically when the flow is deleted

Use it in Power Automate

// After publishing the connector:
// Power Automate → New connection → Custom Connectors → BConcepts Projects API
// The user authorizes with their Azure AD account
// Available actions: "List projects", "Create project", etc.

Conclusion

Custom Connectors turn ad-hoc integrations into reusable assets shared across the whole organization. The investment of creating a well-documented connector with OAuth2 authentication saves hours for every colleague who needs to integrate the same API in future flows.