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Azure Data Factory Web Activity: Integrating REST APIs in Data Pipelines
The Web activity in ADF is the HTTP client that lets your pipeline call external REST APIs—triggering a Logic App, posting a Teams notification, calling a custom API, or invoking any REST endpoint as part of pipeline orchestration. The authentication options matter: Managed Identity authentication (for Azure services that support it), Basic auth, Client Certificate, or no auth for public APIs. The response body is available in subsequent activities via @activity('WebActivity').output.body, enabling conditional logic based on API responses or passing API return values into subsequent activities. I use the Web activity most for: posting pipeline status to Teams channels via incoming webhooks, triggering Logic Apps for approval workflows in Durable Functions-style human-in-the-loop patterns, and calling custom APIs for data enrichment that doesn’t have a native ADF connector.
Basic Web Activity
{
"name": "CallRestApi",
"type": "WebActivity",
"typeProperties": {
"url": "https://api.service.com/v1/data",
"method": "GET",
"headers": {
"Content-Type": "application/json",
"Accept": "application/json"
},
"authentication": {
"type": "MSI",
"resource": "https://api.service.com"
}
}
}
POST Request with Body
{
"name": "PostToApi",
"type": "WebActivity",
"typeProperties": {
"url": "https://api.service.com/v1/process",
"method": "POST",
"headers": {
"Content-Type": "application/json"
},
"body": {
"value": "@json(concat('{\"jobId\": \"', pipeline().RunId, '\", \"tableName\": \"', pipeline().parameters.tableName, '\", \"timestamp\": \"', utcnow(), '\"}'))",
"type": "Expression"
}
}
}
Authentication Methods
API Key Authentication
{
"name": "ApiKeyAuth",
"type": "WebActivity",
"typeProperties": {
"url": "https://api.service.com/data",
"method": "GET",
"headers": {
"X-API-Key": {
"value": "@pipeline().parameters.apiKey",
"type": "Expression"
}
}
}
}
OAuth Bearer Token
{
"name": "GetOAuthToken",
"type": "WebActivity",
"typeProperties": {
"url": "https://login.microsoftonline.com/{tenant}/oauth2/v2.0/token",
"method": "POST",
"headers": {
"Content-Type": "application/x-www-form-urlencoded"
},
"body": "grant_type=client_credentials&client_id={client_id}&client_secret={secret}&scope=https://api.service.com/.default"
}
}
{
"name": "CallApiWithToken",
"type": "WebActivity",
"dependsOn": [
{
"activity": "GetOAuthToken",
"dependencyConditions": ["Succeeded"]
}
],
"typeProperties": {
"url": "https://api.service.com/data",
"method": "GET",
"headers": {
"Authorization": {
"value": "@concat('Bearer ', activity('GetOAuthToken').output.access_token)",
"type": "Expression"
}
}
}
}
Managed Identity Authentication
{
"name": "MsiAuthWebActivity",
"type": "WebActivity",
"typeProperties": {
"url": "https://management.azure.com/subscriptions/{sub}/resourceGroups/{rg}/providers/Microsoft.Sql/servers/{server}/databases?api-version=2021-02-01-preview",
"method": "GET",
"authentication": {
"type": "MSI",
"resource": "https://management.azure.com"
}
}
}
Calling Azure Functions
{
"name": "CallAzureFunction",
"type": "WebActivity",
"typeProperties": {
"url": {
"value": "@concat('https://', pipeline().parameters.functionAppName, '.azurewebsites.net/api/ProcessData')",
"type": "Expression"
},
"method": "POST",
"headers": {
"Content-Type": "application/json",
"x-functions-key": {
"value": "@pipeline().parameters.functionKey",
"type": "Expression"
}
},
"body": {
"value": "@pipeline().parameters.functionInput",
"type": "Expression"
}
},
"linkedServiceName": {
"referenceName": "AzureFunctionLinkedService",
"type": "LinkedServiceReference"
}
}
Error Handling and Retry
{
"name": "WebActivityWithRetry",
"type": "WebActivity",
"policy": {
"timeout": "0.00:10:00",
"retry": 3,
"retryIntervalInSeconds": 30,
"secureOutput": false,
"secureInput": false
},
"typeProperties": {
"url": "https://api.service.com/data",
"method": "GET"
}
}
Handling Web Activity Output
{
"name": "ProcessApiResponse",
"properties": {
"activities": [
{
"name": "CallApi",
"type": "WebActivity",
"typeProperties": {
"url": "https://api.service.com/orders",
"method": "GET"
}
},
{
"name": "CheckResponse",
"type": "IfCondition",
"dependsOn": [
{
"activity": "CallApi",
"dependencyConditions": ["Succeeded"]
}
],
"typeProperties": {
"expression": {
"value": "@greater(length(activity('CallApi').output.data), 0)",
"type": "Expression"
},
"ifTrueActivities": [
{
"name": "ProcessData",
"type": "ForEach",
"typeProperties": {
"items": {
"value": "@activity('CallApi').output.data",
"type": "Expression"
},
"activities": [
{
"name": "InsertRecord",
"type": "SqlServerStoredProcedure",
"typeProperties": {
"storedProcedureName": "sp_InsertOrder",
"storedProcedureParameters": {
"OrderId": { "value": "@item().id" },
"CustomerName": { "value": "@item().customer.name" },
"Amount": { "value": "@item().totalAmount" }
}
}
}
]
}
}
]
}
}
]
}
}
Paginated API Calls
{
"name": "PaginatedApiPipeline",
"properties": {
"variables": {
"hasMorePages": { "type": "Bool", "defaultValue": "true" },
"pageNumber": { "type": "Int", "defaultValue": "1" },
"allResults": { "type": "Array" }
},
"activities": [
{
"name": "FetchAllPages",
"type": "Until",
"typeProperties": {
"expression": {
"value": "@equals(variables('hasMorePages'), false)",
"type": "Expression"
},
"timeout": "0.01:00:00",
"activities": [
{
"name": "FetchPage",
"type": "WebActivity",
"typeProperties": {
"url": {
"value": "@concat('https://api.service.com/data?page=', variables('pageNumber'), '&pageSize=100')",
"type": "Expression"
},
"method": "GET"
}
},
{
"name": "ProcessPage",
"type": "Copy",
"dependsOn": [
{
"activity": "FetchPage",
"dependencyConditions": ["Succeeded"]
}
],
"typeProperties": {
"source": {
"type": "RestSource",
"additionalColumns": [
{
"name": "PageNumber",
"value": {
"value": "@string(variables('pageNumber'))",
"type": "Expression"
}
}
]
},
"sink": { "type": "ParquetSink" }
}
},
{
"name": "CheckMorePages",
"type": "SetVariable",
"dependsOn": [
{
"activity": "ProcessPage",
"dependencyConditions": ["Succeeded"]
}
],
"typeProperties": {
"variableName": "hasMorePages",
"value": {
"value": "@activity('FetchPage').output.hasMorePages",
"type": "Expression"
}
}
},
{
"name": "IncrementPage",
"type": "SetVariable",
"dependsOn": [
{
"activity": "CheckMorePages",
"dependencyConditions": ["Succeeded"]
}
],
"typeProperties": {
"variableName": "pageNumber",
"value": {
"value": "@add(variables('pageNumber'), 1)",
"type": "Expression"
}
}
}
]
}
}
]
}
}
Webhook Integration
{
"name": "WebhookNotification",
"type": "WebActivity",
"typeProperties": {
"url": "https://hooks.slack.com/services/xxx/yyy/zzz",
"method": "POST",
"headers": {
"Content-Type": "application/json"
},
"body": {
"value": "@json(concat('{\"text\": \"Pipeline ', pipeline().Pipeline, ' completed with status: ', pipeline().parameters.status, '\", \"channel\": \"#data-ops\"}'))",
"type": "Expression"
}
}
}
Secure Input/Output
{
"name": "SecureWebActivity",
"type": "WebActivity",
"policy": {
"secureInput": true,
"secureOutput": true
},
"typeProperties": {
"url": "https://api.service.com/sensitive-data",
"method": "POST",
"headers": {
"Authorization": {
"value": "@concat('Bearer ', pipeline().parameters.sensitiveToken)",
"type": "Expression"
}
},
"body": {
"value": "@pipeline().parameters.sensitivePayload",
"type": "Expression"
}
}
}
Best Practices
- Use Managed Identity: When possible, avoid storing credentials
- Set appropriate timeouts: Prevent hanging pipelines
- Handle pagination: For APIs returning large datasets
- Secure sensitive data: Use secureInput/secureOutput
- Implement retry logic: Handle transient failures
The Web Activity opens up endless integration possibilities, allowing Azure Data Factory to orchestrate workflows across diverse systems and services through REST APIs.