Online HAR Viewer & Network Analyzer
Open, inspect, and visualize HTTP Archive (.har) network logs directly in your browser. Interactive latency waterfall charts, response header audits, payload inspection, and zero cloud uploads.
| Method | Request URL | Status | Time |
|---|---|---|---|
| GET | https://api.hifitoolkit.com/v1/auth/session | 200 | 78ms |
| POST | https://api.hifitoolkit.com/v1/telemetry/log | 201 | 45ms |
| GET | https://cdn.hifitoolkit.com/assets/img/logo.svg | 304 | 14ms |
| GET | https://analytics.thirdparty.com/v2/collect | 403 | 124ms |
| content-type | application/json; charset=utf-8 |
| cache-control | no-cache, no-store, must-revalidate |
| server | cloudflare |
| x-response-time | 35ms |
{
"authenticated": true,
"userId": "usr_998412",
"role": "admin",
"expiresAt": "2026-08-20T23:59:59Z"
}The Complete Guide to HTTP Archive (HAR) Files & Network Performance Debugging
The HTTP Archive (HAR) format is a standardized JSON-based container format for capturing web browser interaction logs, network traffic requests, server response headers, cookies, cache policies, and precise execution timings. Standardized by the W3C Web Performance Working Group, HAR files enable software engineers, QA testers, and performance consultants to analyze bottlenecks, slow API calls, and third-party script regressions.
When diagnosing network issues reported by clients or analyzing synthetic monitoring logs, loading raw multi-megabyte JSON HAR dumps in text editors is tedious. The HiFi Toolkit Online HAR Viewer parses the archive structure into an intuitive, two-pane interactive waterfall grid with color-coded status codes and detailed latency breakdowns.
Anatomy of HTTP Timing Breakdown in HAR Logs
How to Inspect HAR Files Online
- Export HAR: In Chrome/Firefox DevTools, navigate to Network → Right Click →
Save all as HAR with content. - Upload File: Click Open HAR File or drag and drop your
.harfile into the viewer. - Audit Traffic: Click any request row to inspect HTTP status, headers, waterfall timing bars, and response bodies.
