Comparing runs
Diff a before/after capture: verdicts, key changes, per-metric deltas, and permalinks.
How a comparison works#
Compare has two zones — a baseline and a current — and each one independently takes a saved analysis, a .har file you drop in, or a live URL Harpoon captures for you. Both sides go through the exact same deterministic engine (see why that matters), then the two results are diffed: an overall verdict, the key changes ranked by impact, deltas for every headline metric (score, transfer bytes, request count, load time), and the request-level changes — what's new, what's gone, what got slower or heavier.
Because the engine is deterministic, any difference in the comparison is a real difference between the captures — capture both the same way (same browser, cold load, page finished) so the diff reflects your change, not your method.
Compare against a live capture#
Signed in on a Patrol or Fleet plan, either zone can be a live URL: give it a page address and Harpoon captures that page as it is right now before diffing. It's the same headless-browser engine and the same usage limits as the Capture page, so each live side counts toward your plan's capture usage the same way a standalone capture does. Set both zones to a live URL and they run in order — baseline first — never two browsers at once.
If a live capture fails — a timeout, a blocked navigation, anything the browser hits — you land back on the picker with the reason, both sources still chosen. Pressing Run again only redoes the leg that failed: an upload or analysis that already resolved is never re-sent.
Signed out, compare works on two .har files. Saved analyses and live URLs both need an account, because both need Harpoon to be able to keep your runs.
The AI comparison report#
The deterministic diff renders instantly. Signed in, the AI's read on the comparison loads alongside it asynchronously — same trust rules as the analysis AI report. Anonymous comparisons get the deterministic report inline, with no model call.
Permalinks, export & sharing#
- Signed-in comparisons are saved and get a permalink you can revisit and send to teammates.
- Export as PDF, HTML, Markdown, or CSV — see Sharing & export.
- Create an opt-in public link for people outside your org — see public share links.