Analyze a HAR file online
Drop a .har file and get a ranked list of what is actually slowing the page down — with the exact bytes and milliseconds each problem costs. Free, no signup.
New to HAR files? Learn what they are and how to export one →
What the analysis covers
This analyzer reads your HAR and runs a deterministic performance engine over every request. It produces a single 0–100 Harpoon Score built from weighted sub-scores — render-blocking, critical path, third parties, cache quality, and asset efficiency — so you can see at a glance how the page did and exactly which dimension pulled it down.
Below the score is a ranked list of findings: oversized JavaScript and images, render-blocking resources, uncompressed responses, weak or missing cache headers, slow requests, redirect chains, and heavy third-party domains. Each finding is quantified — the wasted bytes, the added milliseconds, the number of requests — so you can triage by real impact instead of guessing. Findings are ordered worst-first, and identical input always produces identical results.
Findings first, AI second
The engine discovers every problem deterministically from the numbers in your capture — the AI never invents findings. An AI report then reads that curated list of findings and turns it into a prioritized fix plan in plain English, explaining what to do first and why — on every run, with or without an account.
That separation is deliberate: the analysis you can trust and reproduce comes from the engine; the AI just makes it easier to act on. You get the same score and findings whether or not the AI runs.
From one capture to a habit
A single analysis tells you what to fix today. To keep a page fast, compare a before/after capture to prove a change actually helped, run the analyzer in CI to fail a build that regresses, or monitor a URL on a schedule and get alerted when it slows down. Start by dropping a capture above — everything else is optional.
HAR analysis FAQ
How do I analyze a HAR file?
Export a HAR from your browser DevTools (Network tab → save all as HAR), then drop it on the analyzer above. You get a 0–100 score and a ranked list of findings instantly — no signup, nothing to install.
What does the analysis tell me?
It ranks the real performance problems in the capture — render-blocking scripts, oversized assets, missing compression, weak caching, slow requests, redirect chains, and heavy third parties — and quantifies each one in wasted bytes or added milliseconds, so you know what to fix first.
Is my HAR sent to the AI model?
No. The deterministic engine discovers every finding from your file. Only a small structured summary of those findings and page metadata is sent to the AI to write the explanation — never your raw requests, cookies, query strings, or response bodies.
Is it free?
Yes. Analyzing a HAR with the full score, findings, and AI explanation is free and needs no account. Paid plans add saved history, scheduled monitoring, alerts, and team seats.