Logging & Monitoring APIs with APIM

Overview (Simple Explanation)

Azure API Management (APIM) provides built-in logging and monitoring capabilities. These help you track API usage, detect errors, analyze latency, and troubleshoot requests.

Key logging and monitoring features:

• Diagnostics logs for request/response tracking
• Integration with Application Insights
• Request tracing and policy debugging

Step 1: Enable Diagnostics Logs

Diagnostics logs capture all inbound and outbound traffic, including headers, body, and backend responses.

1. APIM → APIs → Select your API → Diagnostics
2. Click Add diagnostic setting
3. Choose log destination:
   • Log Analytics Workspace
   • Storage Account
   • Event Hub
4. Select logs to capture:
   • All requests
   • All responses
   • Errors only (optional)
5. Click Save

Step 2: Integrate with Application Insights

Application Insights provides real-time analytics, metrics, and telemetry for your APIs.

1. APIM → APIs → Select your API → Settings
2. Enable Application Insights
3. Provide Instrumentation Key from your App Insights resource
4. Choose log verbosity (minimal, normal, or verbose)
5. Click Save

Step 3: Enable Request Tracing

Request tracing helps you debug APIM policies, transformations, and routing issues.

1. APIM → APIs → Select API → Settings
2. Enable Trace Requests
3. Use the Trace tab in Azure Portal to view detailed request flow and policy execution

Step 4: View Metrics and Logs

APIM provides built-in metrics and dashboards to analyze API performance.

• Metrics: Request count, response time, cache hits, throttled requests
• Logs: Detailed diagnostics in Log Analytics or Storage
• Alerts: Configure alerts for failed requests, latency, or other anomalies

Step 5: Common Policies for Logging

You can apply policies to log specific data points for easier troubleshooting:

  @{{
      "requestUrl": context.Request.Url,
      "requestMethod": context.Request.Method,
      "responseCode": context.Response.StatusCode
  }}

This logs the request URL, method, and response code to Application Insights.

Step 6: Troubleshooting Tips

• Use Request Trace to check policy execution order.
• Check Application Insights for failed requests and exceptions.
• Use Filters in Diagnostics logs to focus on specific endpoints or errors.

Final Understanding (One Line)

Enable diagnostics + integrate with App Insights → Track API usage → Troubleshoot & monitor APIs efficiently.