Loki vs SmartUI

Loki is a free, MIT-licensed tool for checking Storybook projects for visual regressions. It captures story screenshots and compares them with reference images, producing visual differences for review. The workflow is to create reference screenshots, run comparisons, review the differences, and approve updated references. Loki is designed for continuous integration, where tests can fail if reference images are missing. Capture targets include Chrome in Docker or locally, Chrome in AWS Lambda, the iOS simulator, and the Android emulator; an AWS Lambda renderer is available for large test suites. Node 16 or later is required. Recent Storybook versions need no extra integration for non-React Native projects, while React Native setup uses an import in `storybook/storybook.js`. Projects can configure Loki in a `package.json` section or supported Loki configuration files. Loki does not start Storybook or simulator and emulator servers, so they need to be running before tests. Documented animation limitations include looping requestAnimationFrame animations, GIFs, SVG animations, native Lottie animations, and React Native Animated.

SmartUI captures application UI screenshots and compares them with baselines to identify visual regressions across browsers, devices, apps, and PDFs. Its Visual AI filters rendering noise and explains meaningful differences, while Smart Ignore can mask dynamic regions and distinguish layout shifts from other changes. Root Cause Analysis compares screenshot differences with code changes and suggests fixes. The listed frameworks include Selenium, Playwright, Puppeteer, Cypress, Appium, Espresso, XCUITest, and Jest. SmartUI describes coverage across 3,000+ browser combinations and 10,000+ real devices, and supports Figma-to-live-UI comparison and PDF checks for text, layout, font, and graphic differences. Git branch-aware baselines work across branches and CI/CD pipelines; diffs and suggestions can be exported to Jira or Slack, with GitHub and GitLab integrations listed. The free plan includes 2,000 screenshots for lifetime use and one month of build history. SmartUI Visual Regression costs $199 a month, billed annually, and includes one year of build history; screenshot volume is selected with the plan.