HAR File Format - Understanding Browser Network Logs
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. ...