BackstopJS vs Diffy

BackstopJS is a free, MIT-licensed tool for visual regression testing of web applications. It captures screenshots and compares them with reference images over time. An in-browser report shows reference, test and visual-difference views, with additional CLI and JUnit reports. BackstopJS supports Puppeteer and Playwright; Playwright can use Chromium, Firefox or WebKit. Scenarios can script clicks, scrolling, hovering, key presses and cookie state. Captures can cover a full document, viewport or selected DOM elements at configured viewport sizes. The documented workflow uses `backstop init`, `backstop test` and `backstop approve` to configure tests, compare captures and update references. Installation works globally or locally through npm, as a standalone CLI or from a Node.js app. CI reporting and integrations include Jenkins, Travis and gulp. Docker can reduce rendering differences, though Chrome Headless in Docker needs substantial memory.

Diffy is a visual regression testing service that captures website pages and compares screenshots to show changes. It can capture pages as logged-in users and test admin pages without requiring code. To help with changing content, users can mock dynamic page elements while checking layout and styles. Diffy detects vertical shifts and provides pixel-perfect comparisons, thumbnails, individual approvals and shareable diff links. AI summaries group changes by type and prioritize them by impact. Listed integrations include GitHub Actions, Jenkins, CircleCI, Playwright, GitHub pull requests, Zapier, Figma, Slack, webhooks and a Claude skills plugin. Local development integrations include DDEV, Lando and Docksal, and an on-premises installation option is listed. The free plan includes 500 screenshots per month, two environments and one month of data retention. Pro costs $67 a month when billed annually and includes 2,000 screenshots per month, multiple environments, CI automation and six months of retention. CI and API access, custom environments and history beyond one month require a paid plan.