Power Platform Custom Connector Creation

Build production-ready Power Platform custom connectors and submit them to the microsoft/PowerPlatformConnectors GitHub repo. This skill covers Independent Publisher and Verified Publisher connector paths.

References: OPENAPI_EXTENSIONS.md | AUTH_PATTERNS.md | POLICY_TEMPLATES.md | CUSTOM_CODE.md | WEBHOOK_TRIGGERS.md | CERTIFICATION.md | EXAMPLES.md | COMMON_MISTAKES.md

First Step: Identify Publisher Type

IMPORTANT — Ask the user before proceeding:

Before generating any connector files or certification guidance, ask the user:

"Are you building an Independent Publisher connector or a Verified Publisher connector?"

• Independent Publisher — You are a community member (MVP, developer, enthusiast) wrapping a third-party API you do not own.
• Verified Publisher — You are the service/API owner and want to publish your own connector.

The answer determines: directory structure, brand color, icon requirements, OAuth support, certification workflow, submission target, and connector title format. Tailor all subsequent guidance to the selected publisher type.

Quick Reference: Independent Publisher vs Verified Publisher

#da3b01

independent-publisher-connectors/

dev

certified-connectors/

dev

microsoft/PowerPlatformConnectors

intro.md

intro.md

Decision rule: If you own the API/service, go Verified Publisher. If you're wrapping a third-party API you don't own, go Independent Publisher.

Getting Started

Required Files

Every connector directory must contain:

apiDefinition.swagger.json

apiProperties.json

readme.md

icon.png

script.csx

Directory Structure

PowerPlatformConnectors/
├── independent-publisher-connectors/
│   └── YourConnector/
│       ├── apiDefinition.swagger.json
│       ├── apiProperties.json
│       ├── readme.md
│       ├── icon.png          (optional)
│       └── script.csx        (optional)
├── certified-connectors/       (verified publishers)
├── custom-connectors/          (samples only)
├── schemas/                    (JSON Schema for validation)
│   ├── apiDefinition.swagger.schema.json
│   └── paconn-apiProperties.schema.json
└── templates/                  (starter templates)

Scaffold a New Connector

# Fork and clone the repo
git clone https://github.com/<your-fork>/PowerPlatformConnectors.git
cd PowerPlatformConnectors
git checkout dev

# Create connector directory
mkdir independent-publisher-connectors/YourConnector
cd independent-publisher-connectors/YourConnector

# Create required files (see EXAMPLES.md for complete templates)

Swagger Definition Structure (apiDefinition.swagger.json)

Critical: Must be OpenAPI 2.0 (Swagger). OpenAPI 3.0 is NOT supported.

If your source API provides an OpenAPI 3.0 definition, convert it before importing:

# Option 1: api-spec-converter CLI (requires Node.js)
npm install -g api-spec-converter
api-spec-converter --from=openapi_3 --to=swagger_2 openapi3.yaml > apiDefinition.swagger.json

# Option 2: Apimatic Transform (https://www.apimatic.io/transformer)
# Upload your 3.0 file → select Swagger 2.0 → download

After conversion, manually verify the output — automated tools may not handle all Power Platform–specific extensions correctly.

{
  "swagger": "2.0",
  "info": {
    "version": "1.0.0",
    "title": "My Service",
    "description": "Short description (30-500 chars). No words 'API', 'Connector', or Power Platform product names.",
    "contact": {
      "name": "Your Name",
      "url": "https://github.com/yourusername",
      "email": "you@example.com"
    }
  },
  "host": "api.myservice.com",
  "basePath": "/v1",
  "schemes": ["https"],
  "consumes": ["application/json"],
  "produces": ["application/json"],
  "securityDefinitions": {},
  "security": [],
  "paths": {},
  "definitions": {},
  "x-ms-connector-metadata": [
    { "propertyName": "Website", "propertyValue": "https://myservice.com" },
    { "propertyName": "Privacy policy", "propertyValue": "https://myservice.com/privacy" },
    { "propertyName": "Categories", "propertyValue": "AI;Business Intelligence" }
  ]
}

Key rules:

• title

  — Maximum 30 characters. Cannot include the words "API", "Connector", "Copilot Studio", or any Power Platform product names. Must end with an alphanumeric character (no trailing punctuation, spaces, or special chars). Must be unique and distinguishable from existing connector titles. Note: the

  (Independent Publisher)

  suffix goes on the PR title, not the connector title in the OpenAPI definition

• description

  — Must be 30-500 characters for certification quality and must stay within the platform import hard limit of 1000 characters. Use plain text only (no HTML tags). Cannot contain "API", "Copilot Studio", or Power Platform product names. Must be free of grammatical and spelling errors. Should concisely describe the main purpose and value of the connector

• contact

  — Include

  name

  ,

  url

  , and

  email

  with a valid email address

• x-ms-connector-metadata

  — Required array with Website, Privacy policy, and Categories. The

  Categories

  value must be a semicolon-delimited string from these allowed values:

  AI

  ,

  Business Management

  ,

  Business Intelligence

  ,

  Collaboration

  ,

  Commerce

  ,

  Communication

  ,

  Content and Files

  ,

  Data

  ,

  Finance

  ,

  Human Resources

  ,

  Internet of Things

  ,

  IT Operations

  ,

  Lifestyle and Entertainment

  ,

  Marketing

  ,

  Productivity

  ,

  Sales and CRM

  ,

  Security

  ,

  Social Media

  ,

  Website

• consumes

  /

  produces

  — Always explicitly set to

  ["application/json"]

  for JSON APIs. Do not omit these fields even if the API only handles JSON — being explicit prevents content-type mismatches

• schemes

  — Must include

  "https"

  (HTTP not allowed for production connectors)

• host

  — Production host URL only. Staging, dev, and test host URLs are not allowed. Base hostname only, no path segments

File formatting:

• Use soft tabs with 4 spaces for indentation — no hard tabs
• Remove trailing whitespace from all lines
• Structure the file in this order: swagger version → info → host/schemes → consumes/produces → paths → definitions → parameters

Operations (Paths)

Define actions and triggers in the

paths

"paths": {
  "/items": {
    "get": {
      "operationId": "ListItems",
      "summary": "List all items",
      "description": "Retrieves a list of all items from the service.",
      "x-ms-visibility": "important",
      "parameters": [
        {
          "name": "status",
          "in": "query",
          "type": "string",
          "x-ms-summary": "Status",
          "description": "Filter items by their current status.",
          "x-ms-visibility": "advanced"
        }
      ],
      "responses": {
        "200": {
          "description": "Success",
          "schema": { "$ref": "#/definitions/ItemList" }
        },
        "400": {
          "description": "The request was invalid or malformed."
        },
        "404": {
          "description": "The requested resource was not found."
        }
      }
    },
    "post": {
      "operationId": "CreateItem",
      "summary": "Create an item",
      "description": "Creates a new item in the service.",
      "parameters": [
        {
          "name": "body",
          "in": "body",
          "required": true,
          "schema": { "$ref": "#/definitions/CreateItemRequest" }
        }
      ],
      "responses": {
        "201": {
          "description": "Created",
          "schema": { "$ref": "#/definitions/Item" }
        }
      }
    }
  }
}

Key rules:

• operationId

  — Must be PascalCase (capitalize every word), unique across all operations. Remove all non-alpha characters — no hyphens, underscores, or spaces (e.g.,

  get_user-info

  →

  GetUserInfo

  )

• summary

  — Required for every operation. Must be sentence case, 80 characters or fewer, and must end with an alphanumeric character (no trailing punctuation, spaces, or special characters). Must contain only alphanumeric characters or parentheses — no slashes (

  /

  ). As a naming convention: start with "List" when the operation returns multiple records, "Get" when it returns a single record. For triggers, use the format: "When a [event]" (e.g., "When a task is created")

• summary

  and

  description

  must not have the same text — the description should provide additional information beyond the summary

• description

  — Required for every operation and parameter. Must be a full, descriptive sentence ending in punctuation. Must not contain URLs or HTML markup. Must be in English and free of grammatical or spelling errors
• Input description UX style — Parameter descriptions are shown as helper text in Power Automate/Power Apps. Keep them concise and action-oriented: avoid repetitive prefixes like "Filter the response by"; prefer short forms like "Location code (ISO-3).", "Reference period start (inclusive).", or "Select from dropdown." for long enum lists

Description Style Examples (Parameters)

Use this quick mapping when rewriting parameter helper text for designer UX.

Filter the response by location code.

Location code (ISO-3).

Filter entries to include rows where the reference period overlaps with or extends beyond this date...

Reference period start (inclusive).

Filter entries to include rows where the reference period overlaps with or begins prior to this date...

Reference period end (inclusive).

The has_hrp flag. The has_hrp flag indicates whether...

Whether the location has a Humanitarian Response Plan (HRP).

... available values are described in documentation.

Allowed values: csv, json.

Allowed values: value1, value2, value3, ...

Select from dropdown.

See https://... for details.

See location metadata.

• x-ms-summary

  — Required on every parameter and schema property. Use Title Case, matching the parameter

  name

  but without hyphens or underscores (e.g.,

  name: "form_name"

  →

  x-ms-summary: "Form Name"

  )

• x-ms-visibility

  — Controls visibility:

  "important"

  (always shown),

  "advanced"

  (hidden under menu),

  "internal"

  (hidden from user)
• Response schemas — Each operation should have only one response with a schema, which should be the

  2XX

  success response (200 or 201). The

  default

  response should NOT have a schema definition — schemas belong on expected success responses only. For error responses (

  4xx

  ,

  5xx

  ), provide meaningful descriptions but remove the schema property. Empty response schemas are not allowed (except when dynamic). Empty operations are not allowed — every operation must have at least one response
• Boolean filters — Parameters that represent true/false flags (for example

  has_hrp

  ,

  in_gho

  ,

  is_hxl

  , and origin/asylum variants) should use

  "type": "boolean"

  instead of

  "string"

• Path parameters — All path parameters (e.g.,

  /items/{itemId}

  ) must include

  "x-ms-url-encoding": "single"

  and must be marked

  "required": true

• Reserved names — A parameter cannot be named

  connectionId

  (reserved by the platform)
• Swagger 2.0 parameter typing — Every non-body parameter (

  in: query

  ,

  header

  ,

  path

  ,

  formData

  ) must include a

  type

  field. Missing

  type

  frequently causes APIM import failures such as

  JSON is valid against no schemas from 'oneOf'

• GET operations — Cannot have body or form data parameters

• collectionFormat: "multi"

  is NOT supported — The Custom Connector wizard rejects array parameters with

  "collectionFormat": "multi"

  . Workaround: change the parameter type from

  array

  to

  string

  , accept comma-separated values, and use custom code (

  script.csx

  ) to split them into repeated query parameters. See CUSTOM_CODE.md Pattern 5 and COMMON_MISTAKES.md entry #33
• Remove empty properties from operations and parameters unless they are explicitly required

Recommended preflight lint before

pac connector create

pac connector update

• Confirm every non-body parameter has a

  type

• Confirm every action/operation has a non-empty

  description

• Confirm path parameters are

  required: true

  with

  x-ms-url-encoding: "single"

• Confirm each operation has exactly one success response schema
• Confirm every

  definitions.*.properties.*

  entry has an explicit schema discriminator (

  type

  ,

  $ref

  ,

  enum

  ,

  anyOf

  ,

  oneOf

  , or

  allOf

  ) so properties are never ambiguous during WADL conversion
• Confirm every array schema has explicit

  items

  typing/ref metadata (no

  "items": {}

  placeholders)
• Confirm no

  readOnly: true

  schema properties are listed in any definition

  required

  array
• Confirm there are no empty parameter/response/schema objects such as

  {}

  after automated transforms
• Confirm boolean-like flags (

  has_*

  ,

  in_*

  ,

  is_*

  ) are typed as

  boolean

  where semantically correct
• Confirm parameter descriptions are concise helper text (no repetitive "Filter the response by" boilerplate)
• Parse-check the file before deploy (

  python -c "import json;json.load(open('apiDefinition.swagger.json',encoding='utf-8'))"

  ) to catch malformed JSON and trailing/extra data
• Check for missing operation descriptions (

  python -c "import json; s=json.load(open('apiDefinition.swagger.json',encoding='utf-8')); missing=[(m.upper(),p,o.get('operationId')) for p,ms in s.get('paths',{}).items() for m,o in ms.items() if isinstance(o,dict) and not (isinstance(o.get('description'),str) and o.get('description').strip())]; print('missing_description_count',len(missing)); [print(x) for x in missing[:200]]"

  )
• If converting from OpenAPI 3.x, run a second pass to ensure nullable fields were translated into valid Swagger 2.0 schemas (avoid leaving properties with only

  description

  /

  title

  )
• Confirm nullable primitives use Swagger 2.0-compatible patterns (

  type

  +

  x-nullable: true

  ) and avoid OpenAPI 3 style unions like

  "type": ["integer", "null"]

Definitions (Schemas)

Define reusable data models in the

definitions

$ref

Key rules:

• All objects under

  properties

  must include both a

  description

  and

  title

  property, even when nested — unless the object contains a

  $ref

  property
• Every property schema must include an explicit schema discriminator (

  type

  ,

  $ref

  ,

  enum

  ,

  anyOf

  ,

  oneOf

  , or

  allOf

  ); do not leave property definitions as metadata-only objects

• title

  — Must be in Title Case. Must not contain URLs

• description

  — Must be a full sentence with proper punctuation. Must not contain URLs
• Keep all other existing properties of the definition intact
• Remove

  default

  values from objects inside

  properties

  (defaults belong on operation parameters, not schema definitions)
• If a

  number

  or

  integer

  property's description mentions minimum or maximum values, add explicit

  minimum

  and/or

  maximum

  properties to the schema
• Nullable fields (Swagger 2.0) — Represent nullable scalar properties with

  x-nullable: true

  on the property schema. If upstream data can omit or null a field, remove that field from response

  required

  arrays. Do not use array

  type

  unions such as

  ["integer", "null"]

"definitions": {
  "Task": {
    "type": "object",
    "properties": {
      "id": {
        "type": "string",
        "title": "Task ID",
        "description": "The unique identifier for the task.",
        "x-ms-summary": "Task ID"
      },
      "name": {
        "type": "string",
        "title": "Task Name",
        "description": "The display name of the task.",
        "x-ms-summary": "Task Name"
      },
      "priority": {
        "type": "integer",
        "title": "Priority",
        "description": "The priority level of the task, from 1 (highest) to 5 (lowest).",
        "x-ms-summary": "Priority",
        "minimum": 1,
        "maximum": 5
      },
      "project": {
        "$ref": "#/definitions/Project"
      }
    }
  }
}

Note: The

project

$ref

title

description

OpenAPI Extensions Quick Reference

summary

x-ms-summary

description

x-ms-visibility

important

advanced

internal

x-ms-trigger

"single"

"batch"

x-ms-trigger-hint

x-ms-notification-content

x-ms-notification-url

x-ms-dynamic-values

x-ms-dynamic-list

x-ms-dynamic-schema

x-ms-dynamic-properties

x-ms-capabilities

x-ms-api-annotation

x-ms-url-encoding

"double"

"single"

x-ms-connector-metadata

x-ms-no-generic-test

x-ms-safe-operation

Copilot Studio / AI extensions:

x-ms-name-for-model

x-ms-description-for-model

x-ms-media-kind

"image"

"audio"

Extended format types:

date-no-tz

email

html

uri

uuid

See OPENAPI_EXTENSIONS.md for detailed examples of each extension.

Dynamic Dropdown Pattern (Metadata Endpoints)

For connectors with metadata operations (for example, location/sector/org catalogs), use

x-ms-dynamic-values

{
  "name": "location_code",
  "in": "query",
  "type": "string",
  "required": false,
  "x-ms-summary": "Location Code",
  "description": "Filter the response by location code.",
  "x-ms-dynamic-values": {
    "operationId": "GetLocationApiVMetadataLocationGet",
    "parameters": {
      "output_format": "json",
      "limit": 10000,
      "offset": 0
    },
    "value-collection": "data",
    "value-path": "code",
    "value-title": "name"
  }
}

Guidance:

• Map frequently reused filters (location/admin1/admin2/sector/org/org-type/commodity/market) to metadata operations
• Use

  value-collection

  to match the response payload root (commonly

  data

  )
• Avoid applying dynamic-values on the same metadata source action itself
• Provide stable defaults for source operation parameters (

  output_format

  ,

  limit

  ,

  offset

  )

Authentication Quick Reference

Configure auth in

apiProperties.json

connectionParameters

connectionParameterSets

type

securestring

oauthSetting

aad

oauthSetting

oauth2

oauth2generic

securestring

connectionParameterSets

Note: Multi-auth connectors use

connectionParameterSets

connectionParameters

pac connector

paconn

API Key example (apiProperties.json):

{
  "properties": {
    "connectionParameters": {
      "api_key": {
        "type": "securestring",
        "uiDefinition": {
          "constraints": { "clearText": false, "required": "true", "tabIndex": 2 },
          "description": "Your API key from the service dashboard",
          "displayName": "API Key",
          "tooltip": "Provide your API key"
        }
      }
    },
    "iconBrandColor": "#da3b01",
    "capabilities": [],
    "publisher": "Your Name",
    "stackOwner": "Service Company Name"
  }
}

Critical: Independent Publisher

iconBrandColor

"#da3b01"

See AUTH_PATTERNS.md for OAuth 2.0, AAD, and Basic Auth patterns.

Policy Templates

Policy templates transform requests/responses without custom code. Defined in

apiProperties.json

dynamichosturl

setheader

setqueryparameter

routerequesttoendpoint

setproperty

pollingtrigger

updatenextlink

"policyTemplateInstances": [
  {
    "templateId": "setheader",
    "title": "Set Content-Type Header",
    "parameters": {
      "x-ms-apimTemplateParameter.name": "Content-Type",
      "x-ms-apimTemplateParameter.value": "application/json",
      "x-ms-apimTemplateParameter.existsAction": "override",
      "x-ms-apimTemplateParameter.newValue": "application/json"
    }
  }
]

See POLICY_TEMPLATES.md for all templates with examples.

Custom Code (script.csx)

C# code for request/response transformation when policy templates aren't sufficient.

public class Script : ScriptBase
{
    public override async Task<HttpResponseMessage> ExecuteAsync()
    {
        if (this.Context.OperationId == "MyOperation")
            return await HandleMyOperation().ConfigureAwait(false);

        // Forward all other requests unchanged
        return await this.Context.SendAsync(
            this.Context.Request, this.CancellationToken
        ).ConfigureAwait(false);
    }
}

Constraints: .NET Standard 2.0 | 2-minute timeout | 1 MB max file size | One script per connector

Common Pattern: Build Base64 Identifier from Connection Fields

When the upstream API expects a computed identifier (for example

base64("app_name:email")

connectionParameters

script.csx

var appName = GetHeaderValue("app_name")?.Trim();
var email = GetHeaderValue("email")?.Trim();

if (!string.IsNullOrWhiteSpace(appName) && !string.IsNullOrWhiteSpace(email))
{
  var appIdentifier = Convert.ToBase64String(Encoding.UTF8.GetBytes($"{appName}:{email}"));
  // Inject into query/header as required by the API
  // Remove raw app_name/email headers before forwarding
}

Guidance:

• Use UTF-8 before Base64 encoding
• Trim values before encoding
• Remove raw source headers after deriving the computed identifier
• If accepted by the API, set both query and header forms for compatibility
• Prefer deterministic header injection via

  policyTemplateInstances

  +

  setheader

  using

  @connectionParameters('...')

  , then consume those headers in

  script.csx

Example

apiProperties.json

"policyTemplateInstances": [
  {
    "templateId": "setheader",
    "title": "app_name",
    "parameters": {
      "x-ms-apimTemplateParameter.name": "app_name",
      "x-ms-apimTemplateParameter.value": "@connectionParameters('app_name')",
      "x-ms-apimTemplateParameter.existsAction": "override",
      "x-ms-apimTemplate-policySection": "Request"
    }
  }
]

See CUSTOM_CODE.md for full reference with examples.

Webhook Triggers

Mark an operation as a webhook trigger with

x-ms-trigger

"/hooks": {
  "x-ms-notification-content": {
    "schema": { "$ref": "#/definitions/WebhookPayload" }
  },
  "post": {
    "operationId": "WebhookTrigger",
    "summary": "When an event occurs",
    "x-ms-trigger": "single",
    "x-ms-trigger-hint": "To see it work, create a new item in the service.",
    "parameters": [
      {
        "name": "body",
        "in": "body",
        "schema": {
          "type": "object",
          "properties": {
            "callbackUrl": {
              "type": "string",
              "x-ms-notification-url": true,
              "x-ms-visibility": "internal"
            }
          }
        }
      }
    ],
    "responses": { "201": { "description": "Created" } }
  }
}

Requirements: Must also define a DELETE operation so the platform can unregister webhooks. The API must return a

Location

See WEBHOOK_TRIGGERS.md for complete patterns.

Certification & Submission

See CERTIFICATION.md for full step-by-step certification workflows, packaging instructions, and submission details for both publisher types.

Connector Requirements (Both Publisher Types)

Connector Title:

• ≤30 characters, no restricted words (

  API

  ,

  Connector

  ,

  Copilot Studio

  )
• The

  (Independent Publisher)

  suffix goes on the PR title, not the connector title in the OpenAPI definition

Connector Description: 30–500 characters, ≤1000 total, no HTML tags.

Icon (Verified Publisher only): Custom icon required — 100×100 to 230×230 px, PNG, non-white/non-default background.

OAuth: Currently unsupported for Independent Publisher certification.

Certification Process Summary

dev

intro.md

Office Hours: Tuesdays 3:30–4:30 PM UTC with the Connector Certification Team.

PR Checklist

• All files in correct directory (

  independent-publisher-connectors/

  or

  certified-connectors/

  )
• PR targets

  dev

  branch (never

  master

  )

• apiDefinition.swagger.json

  passes swagger validation (use Solution Checker)

• apiDefinition.swagger.json

  is valid JSON (no trailing/extra data) and contains no empty

  {}

  parameter/response/schema placeholders

• apiProperties.json

  matches schema

• readme.md

  /

  intro.md

  follows template (Publisher, Prerequisites, Operations, Credentials, Known Issues)
• No secrets or real API keys in any file
• Connector title is ≤30 characters, no restricted words ("API", "Connector", "Copilot Studio")
• Connector description is 30-500 characters
• Connector description is <= 1000 characters and contains no HTML tags
• Host URL is a production URL (no staging/dev/test URLs)
• Response schemas provided on success responses only (not on

  default

  response)
• All

  definitions.*.properties.*

  entries have explicit schema type/ref metadata (no ambiguous properties during OpenAPI→WADL conversion)

• x-ms-connector-metadata

  array present with Website, Privacy policy, Categories
• All summaries are ≤80 chars, end with alphanumeric, no slashes
• Every action/operation has a non-empty

  description

• All descriptions are full sentences ending in punctuation, no URLs
• Summary and description text are not identical for any operation or parameter
• All path parameters have

  required: true

  and

  x-ms-url-encoding: "single"

• All

  operationId

  values are PascalCase with no non-alphanumeric characters
• For OAuth connectors:

  "redirectMode": "GlobalPerConnector"

  (not

  "Global"

  )
• For Independent Publisher:

  iconBrandColor

  is

  "#da3b01"

• For Independent Publisher with OAuth: detailed instructions for creating the OAuth app
• At least 10 successful calls per operation tested
• Screenshots of 3+ unique operations working in a Flow (Independent Publisher)
• All strings are in English, free of spelling/grammar errors
• JSON uses 4-space indentation, no trailing whitespace
• Package validated with ConnectorPackageValidator.ps1

CLI Deployment

Two CLI tools can deploy custom connectors. Power Platform CLI (

pac

paconn

pac connector

paconn

winget install Microsoft.PowerPlatformCLI

pip install paconn

pac auth create

paconn login

--solution-unique-name

pac connector init

pac connector list

paconn validate --api-def ...

Power Platform CLI (

pac connector

)

# Install (Windows)
winget install Microsoft.PowerPlatformCLI

# Or install via dotnet
dotnet tool install --global Microsoft.PowerApps.CLI.Tool

# Authenticate
pac auth create --environment <environment-url-or-id>

# Scaffold a new connector (generates starter apiProperties.json)
pac connector init \
  --connection-template OAuthAAD \
  --generate-script-file \
  --generate-settings-file \
  --outputDirectory MyConnector

# List connectors in current environment
pac connector list

# Create a connector
pac connector create \
  --api-definition-file apiDefinition.swagger.json \
  --api-properties-file apiProperties.json

# Create with icon, custom code, and add to a solution
pac connector create \
  --api-definition-file apiDefinition.swagger.json \
  --api-properties-file apiProperties.json \
  --icon-file icon.png \
  --script-file script.csx \
  --solution-unique-name MySolution

# Update an existing connector
pac connector update \
  --api-definition-file apiDefinition.swagger.json \
  --api-properties-file apiProperties.json \
  --connector-id <connector-id>

# If connector uses custom code, ALWAYS include script file on update
pac connector update \
  --api-definition-file apiDefinition.swagger.json \
  --api-properties-file apiProperties.json \
  --script-file script.csx \
  --connector-id <connector-id>

# Download a connector's files
pac connector download \
  --connector-id <connector-id> \
  --outputDirectory ./MyConnector

paconn CLI (Legacy)

# Install the CLI
pip install paconn

# Authenticate
paconn login

# Create a connector
paconn create --api-def apiDefinition.swagger.json --api-prop apiProperties.json

# With custom code and icon
paconn create --api-def apiDefinition.swagger.json --api-prop apiProperties.json \
  --script script.csx --icon icon.png

# Update an existing connector
paconn update --api-def apiDefinition.swagger.json --api-prop apiProperties.json \
  --connector-id <connector-id>

# Validate swagger definition
paconn validate --api-def apiDefinition.swagger.json

# Download connector files
paconn download -e <environment-id> -c <connector-id>

Tip: Both CLIs support a

settings.json

file to store environment, connector ID, and file paths — avoiding repetitive flags on every command. When using

paconn

, always download first as a backup before running

update

.

Reliability note:

pac connector update

with

--script-file

can intermittently fail with

CustomScriptProvisioningFailed

(often surfaced as upstream 502). This is commonly transient; retry the same command after a short delay before changing connector files.

README Template

# Service Name
Short description of the service (2-3 sentences).

## Publisher: Your Name

## Prerequisites
- An account with [Service Name](https://service.com)
- An API key (obtained from Settings > API Keys)

## Supported Operations
### List Items
Retrieves all items from your account.

### Create Item
Creates a new item with the specified properties.

## Obtaining Credentials
Step-by-step instructions for getting API credentials.

## Known Issues and Limitations
- Rate limited to 100 requests per minute
- Maximum 1000 items per response

## Deployment Instructions
Run one of the following commands:
\`pac connector create --api-definition-file apiDefinition.swagger.json --api-properties-file apiProperties.json\`
or (legacy):
\`paconn create --api-def apiDefinition.swagger.json --api-prop apiProperties.json\`

Pagination Support

For connectors to leverage Power Platform's built-in paging, the API must return responses following this pattern:

{
  "nextLink": "https://api.example.com/items?page=2",
  "value": [
    { "id": "1", "name": "Item 1" },
    { "id": "2", "name": "Item 2" }
  ]
}

Requirements:

• value

  — Array of result items (required on every page)

• nextLink

  — Full URI to the next page (present only when more pages exist; omit on the final page)
• Return HTTP 200 for all paginated responses

When the last page is reached, omit

nextLink

Important runtime caveat (custom code):

• Do not rely on

  script.csx

  to reshape pagination payloads for built-in auto paging.
• In practice, follow-up requests triggered internally by platform auto-pagination may bypass custom response transformation logic.
• If page 1 is transformed to include

  value

  /

  nextLink

  but the upstream API returns a different shape on subsequent pages (for example

  data

  /

  next

  ), built-in pagination can still fail.

Recommended approach:

• Prefer native upstream pagination contracts for built-in paging (

  value

  +

  nextLink

  on every page).
• If upstream payloads are non-standard and cannot be changed, implement manual pagination in the flow (Do Until) or create a dedicated custom action that fetches/aggregates pages explicitly.

Pagination decision tree (use this before implementing):

1. Can the upstream API return

   value

   +

   nextLink

   on every page?

• Yes → Use built-in connector pagination.
• No → Continue to step 2.

2. Can

   updatenextlink

   policy safely map the API's paging model?

• Yes → Use

  updatenextlink

  + built-in pagination.
• No → Continue to step 3.

3. Need all records in a single action output?

• Yes → Build a dedicated custom "fetch all pages" action.
• No → Use manual pagination in Flow (

  Do Until

  ) and process page-by-page.

Rule of thumb: If pagination correctness depends on response reshaping in

script.csx

If the API uses non-standard pagination (e.g.,

page

limit

1. Use the

   updatenextlink

   policy template to rewrite the pagination URL into the

   nextLink

   format Power Platform expects
2. Build pagination logic in a Power Automate flow using a Do Until loop that increments the page parameter until no more results are returned

Add

limit

page

{
  "name": "limit",
  "in": "query",
  "type": "integer",
  "required": false,
  "x-ms-summary": "Page Size",
  "description": "The number of items to return per page."
},
{
  "name": "page",
  "in": "query",
  "type": "integer",
  "required": false,
  "x-ms-summary": "Page Number",
  "description": "The page number of results to retrieve."
}

Using AI to Accelerate Development

Leverage AI assistants to generate boilerplate OpenAPI extensions and documentation. This is especially valuable when an API has many operations or parameters that each need

x-ms-summary

description

title

Generating OpenAPI extensions prompt:

Acting as a Power Platform developer, I would like your assistance in writing a custom connector. I will provide each path for the API. Include the following:

• A

  summary

  and

  description

  attribute for each path
• A

  description

  and

  x-ms-summary

  attribute for each path parameter and response property; the

  x-ms-summary

  should read like a title for the name field
• A

  title

  ,

  description

  , and

  x-ms-summary

  attribute for each response property; the

  title

  and

  x-ms-summary

  will be the same
• If the

  name

  attribute is used in the

  description

  , then update the description to use the new

  title

  attribute

Please update the file with those additional attributes and provide it back to me. Here is the first path:

<paste path here>

Generating README prompt:

Acting as a technical writer, create a README.MD file for the custom connector. Below is the template — do not deviate from it. When generating the operations, include all input attributes and use the friendly names.

TEMPLATE:

# {Connector Title}
{Description from the OpenAPI info.description}

## Publisher: {Your Name}

## Prerequisites
{How to get an account and API credentials}

## Supported Operations
### {Operation Summary}
{Operation description}
- **Inputs:** `{Param x-ms-summary}`: {param description}
- **Outputs:** `{Property title}`: {property description}

## Obtaining Credentials
{Step-by-step instructions}

## Known Issues and Limitations
{Current limitations or "Currently, no known issues or limitations exist."}

OPENAPI FILE:

<paste full apiDefinition.swagger.json>

Tips:

• Process paths individually for APIs with many operations — large files may exceed context limits
• Always review and validate AI output against the coding standards before submission
• AI works best when the source API has comprehensive documentation

Testing and Debugging

After importing the connector into Power Platform via the Custom Connector Wizard or CLI:

1. Test every operation in the connector's Test tab — run at least 10 successful calls per operation
2. Use the Swagger Editor toggle in the custom connector editor for quick inline edits to fix validation errors
3. Common schema validation fixes:
   • Remove

     required

     arrays from response schemas — if the API doesn't always return every field, the

     required

     constraint causes validation failures. Keep

     required

     on request body schemas but remove from response schemas
   • Fix type mismatches — if the API returns a string where the schema says integer (or vice versa), update the schema to match actual API behavior
   • Remove empty schema properties — empty

     properties: {}

     on responses can cause issues
4. Re-test after every change — iterate until all operations pass cleanly
5. Create test flows in Power Automate using 3+ unique operations to verify end-to-end behavior and capture screenshots for PR submission

Post-Deploy Verification (Recommended)

After

pac connector create

pac connector update

1. Download the deployed connector files using

   pac connector download --connector-id <id>

2. Perform semantic JSON comparison between local and downloaded files
3. Focus on functional parity for:

• OpenAPI paths/parameters/responses

• x-ms-dynamic-values

  mappings

• connectionParameters

  and script wiring

4. Treat these as common platform-managed non-functional differences unless behavior changed:

• policyTemplateInstances

  may be auto-added

• publisher

  or

  stackOwner

  may differ/appear blank in downloaded

  apiProperties.json

Best Practices

Do:

• Use

  x-ms-summary

  on every parameter and schema property (controls designer labels)
• Use

  x-ms-visibility: "internal"

  for parameters with fixed values (e.g.,

  api-version

  )
• Provide default values for all

  internal

  required parameters
• Include complete response schemas on success responses only (enables dynamic content in flows)
• Use

  $ref

  definitions and

  $ref

  parameters for reusable schemas and shared parameters
• Test with the custom connector wizard before submitting PR — run at least 10 successful calls per operation
• Run Solution Checker and ConnectorPackageValidator.ps1 before submitting
• Use policy templates before reaching for custom code
• Use PascalCase for

  operationId

  — remove all non-alpha characters
• Keep

  summary

  to 80 characters or fewer, sentence case, ending with an alphanumeric character
• Ensure summaries contain only alphanumeric characters or parentheses — no slashes
• Start summaries with "List" (returns many) or "Get" (returns one); for triggers: "When a [event]"
• Make sure

  summary

  and

  description

  have different text on every operation/parameter
• Write

  description

  as full sentences ending in punctuation — no URLs
• Keep parameter helper text concise for designer UX; avoid repetitive boilerplate and long non-clickable references
• Add

  title

  (Title Case) and

  description

  (full sentence) to all definition properties (skip for

  $ref

  )
• Add

  "x-ms-url-encoding": "single"

  and

  "required": true

  to all path parameters
• Add

  minimum

  /

  maximum

  when number/integer ranges are known
• Use

  type: "boolean"

  for true/false inputs instead of

  string

  flags
• For nullable response primitives, use

  x-nullable: true

  and remove from

  required

  when null/omitted is possible
• Ensure all text is in English and free of grammatical/spelling errors
• Capitalize abbreviations to avoid translation issues
• Use

  "redirectMode": "GlobalPerConnector"

  for all OAuth connectors
• Use 4-space soft tabs and remove trailing whitespace in JSON files
• Use only production host URLs (no staging, dev, or test URLs)
• Explicitly set

  consumes

  and

  produces

  to

  ["application/json"]

  — don't rely on defaults
• Back up connector files using source control before running

  update

  commands
• For APIs with multiple cloud endpoints (e.g., commercial, GCC, GCC High, DoD), use the

  dynamichosturl

  policy template to let users select the correct endpoint at connection time

Don't:

• Use OpenAPI 3.0 — must be Swagger 2.0
• Include real API keys or secrets in files (use dummy values:

  <<Enter your API key>>

  )
• Submit PR to

  master

  branch (always target

  dev

  )
• Leave

  x-ms-connector-metadata

  empty or missing
• Use wrong brand color for Independent Publisher (must be

  #da3b01

  )
• Skip response schemas (breaks dynamic content in Power Automate)
• Put schemas on the

  default

  response — schemas belong on explicit success responses (200/201) only
• Exceed 1 MB for the OpenAPI definition file
• Put schemas on error responses (4xx/5xx) — descriptions only
• Leave

  default

  values on definition properties (only on operation parameters)
• Include empty properties unless they are required
• Put URLs in

  title

  or

  description

  fields
• Name any parameter

  connectionId

  (reserved by the platform)
• Include body or form data parameters on GET operations
• Use

  "redirectMode": "Global"

  — must be

  "GlobalPerConnector"

  (mandatory since Feb 2024)
• Exceed 30 characters for connector title
• Include

  required

  arrays on response schemas — they cause validation failures when the API omits optional fields
• Use OpenAPI 3 nullable union syntax in Swagger 2.0 files (for example

  "type": ["integer", "null"]

  )

Known limitation: When using

paconn

stackOwner

apiProperties.json

paconn update

stackOwner

paconn

pac connector

See COMMON_MISTAKES.md for a full error catalog with fixes.

Session Learnings

Use this section as a lightweight changelog for practical field learnings that should influence future connector work.

2026-02-18: HDX Connector Session

• Swagger 2.0 strictness: Non-body parameters without

  type

  caused APIM import failures (

  JSON is valid against no schemas from 'oneOf'

  ); adding explicit

  type

  resolved deployment.
• Metadata-driven UX: Mapping metadata endpoints to

  x-ms-dynamic-values

  significantly improved usability by enabling dropdowns for common filter parameters.
• Computed auth pattern: Collecting

  app_name

  +

  email

  as connection parameters and computing

  app_identifier

  in

  script.csx

  (UTF-8 Base64) produced a cleaner auth experience.
• Deterministic parameter flow: For custom code that reads connection values from headers, explicitly map with

  policyTemplateInstances

  +

  setheader

  (

  @connectionParameters('app_name')

  ,

  @connectionParameters('email')

  ) instead of relying on implicit runtime behavior.
• Input normalization: Trimming connection values before encoding prevented malformed identifiers from accidental whitespace.
• Operational reliability:

  pac connector update

  with custom code can intermittently fail with

  CustomScriptProvisioningFailed

  /502; retrying the same command after a short delay often succeeds.
• Deployment discipline: When a connector has

  script.csx

  , include

  --script-file script.csx

  on every

  pac connector update

  ; otherwise code changes might not be published with schema updates.
• Verification approach: Post-deploy semantic comparison is more reliable than byte-for-byte diff because downloaded files may include platform-managed differences.
• WADL hardening: In addition to property typing, Power Apps WADL conversion also requires typed array

  items

  and rejects

  readOnly

  properties in

  required

  arrays.

2026-02-25: HDX Connector UX & Nullability Session

• Input description UX: Power Automate surfaces parameter

  description

  as helper text; concise descriptions materially improve usability. Prefer short guidance over repeated phrases like "Filter the response by...".
• No dead links in helper text: URLs/HTML anchors in parameter descriptions are not useful in designer helper text; remove them from input descriptions.
• Enum helper strategy: For short enums, include values inline (

  Allowed values: ...

  ). For long enums shown as dropdowns, use concise text such as "Select from dropdown.".
• Boolean correctness: Converted boolean-like query flags (

  has_hrp

  ,

  in_gho

  ,

  origin_*

  ,

  asylum_*

  ,

  is_hxl

  ) from

  string

  to

  boolean

  to align schema with runtime semantics.
• Swagger 2.0 nullable safety: Avoid

  type

  arrays (for example

  ["integer", "null"]

  ) because they can pass some validators but fail connector import/parsing; use

  x-nullable: true

  with scalar

  type

  instead.
• Required vs nullable: If upstream API returns

  null

  or omits fields, remove those fields from response

  required

  arrays rather than coercing values (for example, avoid null→0 data mutation unless explicitly desired).

2026-02-26: HDX Auto-Pagination Session

• Auto-pagination + custom code caveat: Built-in platform auto-pagination may execute follow-up page calls outside custom

  script.csx

  response-shaping assumptions.
• Design implication: Do not depend on custom code to retrofit page 2+ into

  value

  /

  nextLink

  for built-in pagination.
• Preferred fallback: Use manual pagination (Do Until) or a dedicated "fetch all pages" action when the upstream API cannot natively emit Power Platform paging shape on every page.

Troubleshooting

JSON is valid against no schemas from 'oneOf'

type

type: "string"

DefaultResponseHasSchema

default

200

201

default

CustomScriptProvisioningFailed

pac connector update

200

PathParameterMustBeRequired

required: true

"required": true

"x-ms-url-encoding": "single"

ConnectionIdParameterNotAllowed

connectionId

connId

The 'collectionFormat' value 'Multi' is not supported

collectionFormat: "multi"

type: "string"

script.csx

An error occured while converting OpenAPI file to WADL file

type

$ref

definitions.*.properties.*

x-ms-summary

title

x-ms-summary

title

description

x-ms-url-encoding

"x-ms-url-encoding": "single"

redirectMode: "Global"

"redirectMode": "GlobalPerConnector"

For the full error catalog with detailed fixes and code examples, see COMMON_MISTAKES.md.

Related Files

• OPENAPI_EXTENSIONS.md — Detailed reference for all

  x-ms-*

  extensions with examples
• AUTH_PATTERNS.md — API Key, OAuth 2.0 (AAD/Generic), Basic Auth, and Multi-Auth patterns
• POLICY_TEMPLATES.md — All policy template IDs with configuration examples
• CUSTOM_CODE.md — C#

  script.csx

  patterns, ScriptBase class, supported namespaces
• WEBHOOK_TRIGGERS.md — Webhook trigger registration, notification, and deletion patterns
• CERTIFICATION.md — Full certification workflows for Independent and Verified Publishers, packaging, and submission
• EXAMPLES.md — Complete working connector examples for common scenarios
• COMMON_MISTAKES.md — Error catalog with fixes and validation tips