Browser

What is AWS Console API Call Architecture? When you use the AWS Management Console in your browser, it makes API calls to AWS services. Understanding how these calls work is important for debugging, blocking specific services, or understanding the security model. Two Types of API Calls 1. Direct Browser → AWS Service API Example: SSM (Systems Manager) API call Browser JavaScript ↓ https://ssm.us-east-1.amazonaws.com/ ↓ AWS Service responds directly Characteristics: Browser makes HTTPS request directly to service endpoint Uses AWS SigV4 authentication (signed with temporary credentials) Subject to CORS (Cross-Origin Resource Sharing) rules Can be blocked via /etc/hosts Shows in DevTools Network tab with service endpoint URL Example from Session Manager: ...

What is CORS? CORS (Cross-Origin Resource Sharing) is a browser security mechanism that controls which websites can make API calls to other domains. What is an Origin? Origin = Protocol + Domain + Port https://example.com:443 ↑ ↑ ↑ Protocol Domain Port Same-Origin Examples: Origin 1: https://example.com/page1 Origin 2: https://example.com/page2 → Same origin ✓ Cross-Origin Examples: Origin 1: https://example.com Origin 2: https://api.example.com → Different domain = Cross-origin ✗ Origin 1: https://example.com Origin 2: http://example.com → Different protocol = Cross-origin ✗ Origin 1: https://example.com:443 Origin 2: https://example.com:8080 → Different port = Cross-origin ✗ Why CORS Exists Without CORS: ...

What is HAR File? HAR (HTTP Archive) is a JSON format for recording browser HTTP transactions. Created by exporting from Browser DevTools Network tab. How to Create HAR File Chrome/Edge: 1. F12 → Network tab 2. Reload page or perform action 3. Right-click any request 4. "Save all as HAR with content" Firefox: 1. F12 → Network tab 2. Click gear icon → "Save All As HAR" HAR File Structure Overview { "log": { "version": "1.2", "creator": { ... }, "browser": { ... }, "pages": [ ... ], "entries": [ ... ] } } Complete HAR Structure Root Object { "log": { "version": "1.2", "creator": { "name": "WebInspector", "version": "537.36", "comment": "" }, "browser": { "name": "Chrome", "version": "142.0.0.0", "comment": "" }, "pages": [ { "startedDateTime": "2025-11-28T10:30:45.123Z", "id": "page_1", "title": "Example Page", "pageTimings": { "onContentLoad": 1234.5, "onLoad": 2345.6 } } ], "entries": [ { "pageref": "page_1", "startedDateTime": "2025-11-28T10:30:45.123Z", "time": 308.5, "request": { ... }, "response": { ... }, "cache": { ... }, "timings": { ... }, "serverIPAddress": "192.168.1.100", "connection": "443", "_initiator": { ... }, "_priority": "High", "_resourceType": "fetch" } ] } } log Object Top-level container for all HAR data. ...