HAR File Viewer

How to use

1. 1Click Open HAR file to load a .har export from your computer, paste a HAR JSON into the input area, or click Load sample to try the viewer with example data.
2. 2Read the summary cards (Requests, Transfer, Wall-clock, Source) and the Status codes and By type panels to see the overall shape of the recording.
3. 3Use the Slowest requests and Largest responses tables to jump straight to the biggest performance offenders. Click any row to open it in the details panel.
4. 4Filter the waterfall with the search box, the status bucket chips, the method dropdown, or the type dropdown. The summary totals update to reflect what is visible.
5. 5Click a row in the waterfall to open the details panel. Switch between Overview, Headers, Query, Request body, and Response body tabs and use Copy buttons to grab anything you need.
6. 6Use Copy summary for a plain-text report of totals, status breakdown, and the top slow and large rows, or Copy CSV of requests to paste every request into a spreadsheet.

About this tool

HAR File Viewer opens an HTTP Archive (.har) export from any major browser and turns it into a readable performance and request inspector directly in your browser. A HAR file is the JSON dump that Chrome, Edge, Firefox, Safari, Playwright, Charles, and httptoolkit save when you record a network session, and the format is the de-facto way to share a captured page load with another developer. The viewer parses the file with the native JSON parser, normalizes the request and response objects, and presents the network session as four coordinated views. The summary cards show the request count, the total transfer size (using the Chrome _transferSize field when present and falling back to content plus header sizes), the wall-clock span of the recording (computed from the earliest startedDateTime to the latest finish so two simultaneous requests are not double-counted), and the source tool that produced the HAR. The breakdown cards group requests by status bucket (1xx, 2xx, 3xx, 4xx, 5xx, other) so failed and redirected requests jump out at a glance, and by MIME family (HTML, CSS, JavaScript, JSON, XML, Image, Font, Video, Audio) with both request count and total bytes per family. The slowest five requests and the largest five responses surface the biggest performance and budget offenders directly. The waterfall renders every entry as a bar that starts at its real startedDateTime offset and is split into the seven HAR timing phases (blocked, DNS, connect, TLS, send, wait, receive) using the same color order as Chrome devtools, so a slow wait segment (TTFB) is visually distinct from a slow receive segment (large body). The status code uses the same green / blue / amber / red badge color scheme browsers use so failed and redirected requests are obvious. A live filter row supports free-text search across URL, host, method, status text, and content type; per-bucket status filter chips; a method dropdown built from the methods actually present in the file; and a MIME-type dropdown. Clicking any request opens a details panel with five tabs: Overview (host, resource type, start time, content and transfer size, content type, redirect target); Headers (request and response headers in a labelled table with a one-click Copy); Query (URL query string parameters in a labelled table with Copy as query string); Request body (postData text or form-style params); and Response body (decoded text bodies, with base64 binary bodies clearly labelled and skipped). The timing phases are also reproduced as a tall bar with a labelled legend, so you can copy the exact ms cost of each phase. Useful for web developers debugging slow page loads from a remote teammate's recording, QA engineers attaching a HAR to a bug report and confirming what it contains before sending it, performance engineers comparing third-party scripts by size and TTFB, SRE / DevOps teams reviewing API failures captured during an incident, and anyone who would otherwise need to re-open Chrome devtools just to read someone else's network export. Authorization headers, cookies, query strings, and request bodies sometimes contain secrets, and the HAR file stays entirely in your browser. Nothing is uploaded.

Free to use. Works in your browser. No signup, no login.