Inspect HTTP Archive HAR files exported from DevTools with waterfall timelines, MIME filters, status code breakdowns, and payload drawers.
A HAR file records one captured browser session. Use its request details to investigate that session rather than treating it as a universal speed benchmark.
Filter or search for /api/products and inspect its timing breakdown. A long recorded request may include connection, server waiting, and transfer time; the total alone does not identify the cause.
Compare authorization behavior with a successful request if available. Missing or redacted headers cannot be reconstructed, and a status code alone cannot establish why credentials were rejected.
HAR captures can contain cookies, tokens, and personal response data. Use sanitized fixtures when sharing examples or reports.
The Free HAR File Viewer is a professional browser-based diagnostic workspace for inspecting HTTP Archive records exported from Chromium DevTools, Firefox, Safari, and API proxies. Web developers, DevOps engineers, and security auditors rely on HAR logs to diagnose sluggish API endpoints, analyze asset waterfall bottlenecks, trace unexpected redirect loops, and debug failing status codes. All parsing and timeline reconstruction execute strictly within your local browser runtime memory using zero remote servers or telemetry.
Traditional cloud-hosted HAR viewers pose severe security risks by transmitting session cookies, authorization bearer tokens, personal query parameters, and unencrypted response payloads across remote third-party infrastructure. Our tool processes multi-megabyte archives entirely client-side with virtualized table rendering and Web Workers, safeguarding your organization from data leaks while delivering real-time filtering by MIME type, HTTP response code, transfer size, and network timing phases.
Explore detailed waterfall diagrams depicting DNS resolution, TCP handshake, TLS negotiation, Time to First Byte (TTFB), and content download phases. Select individual transaction entries to drill down into raw request headers, query string dictionaries, cookie lifecycles, structured POST payloads, and formatted JSON or HTML response previews with instant clipboard export.
Drag and drop your exported .har file into the upload zone or select it from your device storage. Archives are parsed instantly in client memory.
Isolate failing 4xx and 5xx responses, or narrow inspection down to Fetch/XHR, JavaScript, CSS stylesheets, images, media streams, or documents.
Hover across the interactive timing waterfall to differentiate DNS lookup, initial TCP connect, TLS handshake, TTFB server wait, and content transfer times.
Open the inspector drawer to audit request parameters, response headers, cookies, transmitted forms, and formatted JSON responses with one-click copy.
Color-coded visual timeline segregating DNS lookup, socket connection, SSL negotiation, server wait TTFB, and response payload download duration.
Guarantees that sensitive authentication tokens, customer cookies, and internal staging URLs never touch remote server logging infrastructure.
Instantly filter hundreds of network requests by HTTP status range, resource MIME category, full-text URL query match, and transfer byte thresholds.
Formatted visual tab panes for inspecting HTTP headers, decoded query strings, request payloads, and syntax-highlighted response bodies.
HAR files contain complete network records including session cookies and authorization tokens. Analyze logs strictly in local browser memory without uploading sensitive tokens to public debuggers.
Locate long requests and compare their recorded timing stages with nearby requests from the same capture.
Inspect captured status codes, headers, and response bodies when troubleshooting a development request. Redact credentials before sharing logs.
| Network Timing Phase | DevTools Lifecycle Metric | Primary Performance Impact / Diagnosis |
|---|---|---|
| DNS Lookup | dns (ms) | Domain name resolution latency; high values indicate slow or uncached DNS nameservers |
| Initial TCP Connect | connect (ms) | SYN-ACK roundtrip latency; reflects physical network distance to server |
| SSL / TLS Handshake | ssl (ms) | Cryptographic negotiation time; optimize with TLS 1.3 0-RTT session resumption |
| Server Wait (TTFB) | wait (ms) | Time to First Byte; reveals slow backend database queries and compute bottlenecks |
| Content Download | receive (ms) | Time to stream payload over socket; reduce via gzip/brotli compression and CDNs |
| Blocked / Queued | blocked (ms) | Browser HTTP/1.1 socket saturation (max 6 per origin) or HTTP/2 priority delay |
Yes, on Pro-OmniTools this tool executes 100% locally in your browser sandbox. Unlike public cloud HAR viewers, no request headers, bearer tokens, or response data are transmitted over the internet or logged on any backend server.
Press F12 to open DevTools, switch to the Network tab, reload or perform your workflow, then click the Export HAR icon (downward arrow) in the top toolbar to save the log.
TTFB measures how long the browser waited after sending the request until the web server sent the first byte of response data, representing backend database and server processing time. Content Download measures the duration required to transfer the remaining data over the network.
Yes. Our parser utilizes streaming array processing and virtualized list indexing to smoothly scroll, filter, and inspect HAR files containing hundreds of network transactions without freezing the browser interface.
An internet connection is required to open tools and refresh a temporary session. Processing stays on your device; the handshake sends a random challenge, not files or text inputs. Libraries, fonts or models may download. Local processing cannot remove risks from an untrusted device or extension.
