DiffiCat vs Percy

DiffiCat compares source and target websites to check page existence, content accuracy, and visual changes during migrations. It checks HTTP status codes, broken redirects, authentication walls, and server errors. Content comparisons cover titles, headings, meta descriptions, and body text, using a 90% word-overlap threshold. For visual regression, it captures full-page screenshots and compares pixels with a configurable threshold that defaults to 0%. Viewport widths can be set to 375px, 768px, or 1440px, or customized from 320px to 2560px. A run can cover up to 10,000 pages; leaving the page limit blank removes the cap on discovered pages. DiffiCat can render JavaScript-driven pages, use HTTP basic authentication for both sites, and capture one or multiple URLs without a second site. Exports are ZIP files containing a plain-text report and PNG screenshots. The desktop app keeps outputs on the user's disk and uploads no URLs or screenshots; browser storage lasts for the browser session. The Free plan costs nothing. Desktop use has no limits for personal use; browser limits apply, and commercial use requires a license.

Percy is a visual testing tool that captures DOM snapshots and assets, renders them, and checks them against earlier snapshots to identify visual changes. It can render pages across browsers and platforms, including desktop and mobile, and compare responsive layouts at configurable widths. Percy groups visual changes while filtering noise and freezes animations and other dynamic elements to reduce false positives. Snapshots from tests running on different processes or machines can be grouped into a single build. Its review workflow includes status updates, notifications, comments, baseline management, branch logic, and approval carryforwards. Percy supports web applications, component libraries, end-to-end testing frameworks, static sites, custom SDK integrations, and native mobile applications. The CLI can capture and upload snapshots without an automation script. A free plan includes 5,000 screenshots per month; paid plans have fixed screenshot allocations, with extra screenshots charged at an overage rate. Desktop costs $199 a month billed annually, and Desktop & Mobile costs $599 a month billed annually.