Drop your .har file here
or
Files are parsed locally — nothing is sent to any server
// parse har files and visualize network requests
Parse and visualize HAR files instantly. Analyze HTTP request timing, size breakdown, status codes, and performance bottlenecks directly in your browser.
Drop your .har file here
or
Files are parsed locally — nothing is sent to any server
In Chrome/Firefox DevTools → Network tab → right-click → "Save all as HAR"
Drag your .har file onto the dropzone or click "Browse File"
Explore charts, filter requests, sort by time or size, and export results as CSV
A HAR (HTTP Archive) file is a JSON-format log of a web browser's interactions with a site. This tool parses HAR files entirely in-browser — no upload, no server — and gives you interactive charts, a filterable request table, and a waterfall timeline to pinpoint performance bottlenecks fast.
No. All parsing happens entirely in your browser using JavaScript. Your HAR file never leaves your machine. This makes it safe to analyze HAR files that contain sensitive authentication tokens or cookies.
Open DevTools (F12), go to the Network tab, reproduce the issue, then right-click any request and choose "Save all as HAR with content". Alternatively, click the download icon in the toolbar.
Open DevTools, click the Network tab, then click the gear icon and choose "Save All As HAR". Firefox also supports dragging a recorded session directly to a file.
The waterfall visualizes each request as a horizontal bar positioned by its start time. The length of the bar represents the total duration. This makes it easy to spot sequential bottlenecks and long-tail requests that delay page load.
The tool can handle HAR files up to several hundred MB since parsing is done in-browser using streaming JSON. Very large HAR files (500MB+) may be slow depending on your device's memory and CPU.
Yes. Use the filter bar above the request table to search by URL (which includes domain), filter by HTTP status range, or filter by content type (script, stylesheet, image, fetch, etc.).
Transferred size is the compressed bytes sent over the network (e.g. gzipped). Actual size is the uncompressed resource size. A large gap between the two is good — it means compression is working well.
Yes. Click "Export CSV" to download all requests as a CSV file with URL, method, status, type, size, and timing columns. You can then open it in Excel or Google Sheets for further analysis.
A HAR file analyzer is a tool that reads HTTP Archive (HAR) files and presents the network activity log in a structured, visual format. HAR files are generated by browser developer tools and contain a complete record of every HTTP request made during a page load — including request/response headers, body content, timing data, and status codes.
Without a HAR analyzer, reading a HAR file raw is impractical. Even a simple page load can produce a HAR file with hundreds of entries and megabytes of JSON data. A good analyzer transforms that raw data into actionable insights: which resources are slowest, which domains are contacted, where errors occur, and how resources stack up in the loading waterfall.
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A HAR file is a JSON document with a specific schema defined by the W3C. At its root, it contains a log object with three key sections:
Each entry's timings object breaks a request into phases: DNS lookup, TCP connection, SSL handshake, time to first byte (TTFB), and content download. These phases are what the waterfall chart visualizes.
The waterfall chart is the most powerful view in HAR analysis. Each row represents one request, and the horizontal position shows when it started relative to the beginning of the page load. The width shows how long it took.
Common patterns to look for in a waterfall:
Status codes tell you whether each request succeeded or failed. The HAR analyzer groups them by class:
A healthy HAR file should have mostly 2xx responses, a few 3xx (for cached resources returning 304), and ideally zero 4xx or 5xx. Each error represents a failed network request that may degrade user experience or cause JavaScript errors.
The MIME type chart shows what categories of resources are loaded. Typical breakdowns for a well-optimized page include documents (HTML), scripts (JS), stylesheets (CSS), images, and fetch/XHR calls for API data.
Warning signs in the content type breakdown:
Google Chrome: Open DevTools (F12) → Network tab → reload the page → right-click any request → "Save all as HAR with content". You can also click the download icon (⬇) in the Network tab toolbar.
Mozilla Firefox: Open DevTools → Network tab → click the gear icon → "Save All As HAR". Firefox also lets you drag the session to export it.
Safari: Enable the Develop menu (Preferences → Advanced) → Develop → Show Web Inspector → Network → Export (icon in top right).
Microsoft Edge: Same as Chrome — F12 → Network → right-click → Save all as HAR.
HAR files can contain sensitive information including authentication headers (Authorization, Cookie), API keys embedded in request headers, session tokens, and POST body content including form data and JSON payloads.
Before sharing a HAR file with a colleague or support team, review it for sensitive data. Our tool processes everything locally — your file is never sent to any server — making it safe for analyzing HAR files that contain credentials.
If you do need to share a HAR file externally, consider using a HAR sanitizer to strip sensitive headers and cookies before sharing.
Too many HTTP requests: Each request has overhead for DNS, TCP, and TLS. Bundling assets and using HTTP/2 multiplexing helps reduce this.
Large uncompressed assets: Check that gzip or Brotli compression is enabled on your server. The HAR file will show both the transfer size and the uncompressed size, making this immediately visible.
Missing cache headers: Resources with no Cache-Control headers will be re-downloaded on every page load. Look for static assets (images, fonts, scripts) that should be cached long-term.
Slow third-party scripts: Analytics, chat widgets, and advertising scripts from external domains often appear as long waterfall bars. Consider loading them asynchronously or deferring them after the main content loads.