Free HAR Analyzer: See Every Request on Your Page
Drop a HAR file or a Lighthouse JSON report. Get the waterfall, the third-party vendor breakdown, the compression and cache issues, and a fix list. Nothing leaves your browser.
Chrome, Firefox or Edge export, up to 150 MB
Scored report from PageSpeed or DevTools
How to Analyze a HAR File in Your Browser
A HAR file records what your page really loads. Scripts you forgot about, trackers still running, images served twice. This HAR analyzer reads the file locally and turns it into a fix list in four steps:
- Record the page. Open DevTools with F12, go to the Network tab and reload the page so every request is captured. Right click a request and save all as HAR with content.
- Drop the file. Drag the HAR into the left box. A Lighthouse JSON report is optional in the right box. Both are parsed in a Web Worker, so a 50 MB recording does not freeze the tab.
- Read the verdict. The first tab ranks what matters: secret headers found, third-party weight, missing compression, missing cache headers and duplicate requests. Each line is a sentence you can act on.
- Ship the tickets. Download the fix tickets CSV. Every issue and every third-party domain lands in one table your developer can work through.
The privacy warning comes before anything else. HAR files often carry Cookie and Authorization headers, and this tool tells you exactly how many it found before you paste the file anywhere else.
What the HAR Analyzer Checks
Network logs hold more SEO value than most teams read. This analyzer covers the checks that change rankings and page speed:
- Sanitized file detection. Chrome strips cookies from HAR exports by default. When every entry comes back clean, the tool says the analysis will be blind instead of pretending the file is clean.
- Vendor registry. Every domain is matched against a registry of analytics, ads, chat, video and CDN vendors. You see the vendor name, its category and whether to defer, sample or remove it, with its share of transfer weight.
- Compression and cache. Text resources over 10 KB served without gzip or brotli are flagged with both sizes. Static assets with no Cache-Control header are grouped per host.
- Duplicates and cache busting. The same URL requested twice in one page view, plus query strings that defeat browser caching, are listed with request counts.
- HTTP/1.1 stalls. Eight or more requests over HTTP/1.1 on one host usually means connection queueing. The tool points at the host so you can check your protocol setup.
- Lighthouse merge. Drop the JSON report too and the tool adds category scores, render-blocking resources with wasted milliseconds and the third-party blocking table.
Pair the waterfall with our log file analyzer to see what bots fetch after the page ships, or run the free SEO audit tool for a 50 page crawl with a graded fix list. When the fixes need a prioritized plan, our SEO audit services rank them by revenue impact.
HAR File Analyzer and HAR Viewer for Any Page
A HAR file analyzer turns a raw recording into a table you can read. The same page works as a HAR viewer: inspect every request without installing software. Drop the file and you get a waterfall sorted by time, a per domain breakdown and the size of each response. The HAR file viewer shows headers and payloads on each row, so you spot broken calls before your users do. Export the findings as fix tickets when you are done.
Related Free SEO Tools by Clienvora
- Log File Analyzer - See which bots crawl which URLs after the page ships.
- Page Speed Checker - Run a live speed test on any URL.
- JS SEO Crawler - Check what Google renders after JavaScript runs.
- Redirect Chain Checker - Find hops that slow every request.
Frequently Asked Questions
What is a HAR file?
A HAR file is a JSON log of every network request a page made: scripts, images, API calls, their timings, sizes, headers and status codes. The name HAR stands for HTTP Archive. SEOs and developers use it to see what actually loads on a page instead of guessing.
How do I record and export a HAR file?
Open the page in Chrome or Firefox, press F12 to open DevTools, select the Network tab, reload the page, then right click any request and choose Save all as HAR with content. Drop that file into this analyzer. The whole recording takes under a minute.
Does this tool upload my HAR file?
No. The file is read with local JavaScript and a Web Worker inside your tab. Nothing is sent to a server and nothing is stored after you close the page. HAR files can contain Cookie and Authorization headers, so the analyzer warns you before you share the original file.
Why does my HAR file show no cookies?
Chrome strips Cookie and Authorization headers from exported HAR files by default. The analyzer detects a file with zero sensitive headers across all entries and labels it sanitized, because cookie based tracker analysis on a stripped file is blind, not clean. Re-export with the cookie option enabled if you need cookie evidence.
Can this tool read Lighthouse JSON reports?
Yes. Drop a Lighthouse report next to or instead of a HAR file. The tool shows the category scores, failing audits with their savings, render blocking resources and the third party impact table. A HAR plus a Lighthouse run on the same page gives both the waterfall and the verdict.
What should I fix first after a HAR analysis?
Start with the verdict list. It ranks the issues it finds: uncompressed text on your origin, third party weight you can defer, static assets served without Cache-Control, duplicate requests and HTTP/1.1 connection stalls. Download the fix tickets CSV and hand each row to your developer.