DiffiCat

Overview

DiffiCat is a website migration comparison tool for teams checking whether pages survived a move in working order, content and appearance. It is most compelling for large migrations that need all three checks in one workflow. The desktop app is the better fit for people who want comparison outputs kept locally; browser users trade that privacy for a session-based cloud workflow.

Key features

DiffiCat checks HTTP status codes, broken redirects, authentication walls and server errors, alongside titles, headings, meta descriptions and body text. Its 90% word-overlap threshold gives teams a defined way to flag content differences, though it is not a substitute for editorial review of meaning or accuracy. For visual regression, it captures full-page screenshots and compares them pixel by pixel; the default threshold of 0% is strict, while configurability lets teams adjust sensitivity.

Viewport presets of 375px, 768px and 1440px cover common mobile, tablet and desktop widths. Custom widths from 320px to 2560px give teams room to check other layouts. Each comparison can cover up to 10,000 pages, and a blank page limit means discovered pages are not capped. That breadth is valuable for site moves, although browser quotas can constrain how quickly large jobs run.

Screenshot mode captures one or more URLs without requiring a second site, making it useful for visual snapshots beyond a migration comparison. Playwright renders JavaScript-driven pages before content extraction and screenshots, and HTTP basic authentication works for both source and target sites. Exports bundle a plain-text report and PNG screenshots in a ZIP. Requests to localhost, loopback and private-network addresses are refused, so DiffiCat is not suited to checking sites on those networks.

Pricing

The Free plan costs nothing and is billed Free for Personal Use. The desktop app has no usage limits, making it the strongest option for personal projects where local storage matters. The browser version allows 500 comparison runs per hour, 200 page discoveries per hour and 2,000 pages per day. Those caps matter for repeated or high-volume browser work, and commercial use requires a license.

Commercial users should factor in that license requirement before adopting the free plan. The desktop app keeps outputs on disk and uploads no URLs or screenshots, while the browser version stores reports and screenshots in Google Cloud Storage for the duration of the browser session. That difference makes the desktop app the clear choice for privacy-conscious users.

Platforms

DiffiCat is available on Linux, macOS, Windows and the web. The latest release provides macOS DMG files, a Windows 64-bit EXE installer and a Linux x64 AppImage. Releases include code signing, macOS notarization, SHA-256 checksums and GPG signatures. The product supports automated test execution and desktop, mobile and tablet device coverage through its viewport controls.

Who it's for

DiffiCat suits migration teams that need to check page availability, copy and visual changes across large sites, particularly when a run may involve thousands of pages. It also fits individuals who want a no-cost desktop option for personal use or need screenshot capture without supplying a comparison site. It is a weaker fit for commercial users unwilling to obtain a license, or browser users whose workload exceeds the hourly and daily caps.

Pros and cons

• Pros: Availability, content and visual checks are combined, so migration teams can catch several classes of problems in one comparison workflow.
• Pros: Runs can cover up to 10,000 pages, with no cap on discovered pages when the page limit is blank.
• Pros: The desktop app has no usage limits, uploads no URLs or screenshots, and keeps outputs on disk.
• Cons: Free commercial use requires a license, so the zero-cost plan is specifically for personal use.
• Cons: Browser usage has hourly run and discovery caps plus a 2,000-page daily cap, which can slow larger workloads.
• Cons: Browser reports and screenshots are stored in Google Cloud Storage during the session rather than kept only on the user's disk.

Alternatives

Choose TestCafe if you want a free, open-source test runner under the MIT license, rather than a tool centered on migration comparisons. CloudQA is a better fit for automated test creation and local execution, with unlimited API tests, seven days of test history and Chrome in its free plan.

Percy is an option for teams prepared to pay for screenshot allowances: its Desktop plan is $199 a month billed annually for 10,000 screenshots per month, while Desktop & Mobile is $599 a month billed annually for 25,000. Selenium suits those seeking open-source browser automation tools and libraries instead of a packaged migration checker.

Happo may suit teams prioritizing visual and accessibility testing, with 5,000 snapshots per month on its free plan. Screenster is worth considering for users who prefer its free allowance of one concurrent test and 100 local or 50 cloud runs per user per month.

Argos is an alternative for users wanting an open-source, MIT-licensed SDK and platform, with up to 5,000 screenshots in its free Hobby plan. BackstopJS is a free, open-source MIT-licensed option installed with npm. Browse more options in Browser Testing Software.

Verdict

DiffiCat is a strong choice for personal-use migration work that needs broad page coverage, content checks and pixel comparisons in one tool, especially when the desktop app's local-only handling is important. Its principal drawback is the commercial-use license requirement, with browser quotas and cloud session storage further narrowing that option. Commercial teams should look elsewhere unless they are prepared to license it.