Happo vs Loki
Happo
happo.io
Loki
loki.js.orgSide by side
| Figure | Happo | Loki |
|---|---|---|
| Price from | $149/mo | Free |
| Free plan | Yes | Yes |
| Free trial | Yes | — |
| Open source | — | — |
| Web | Yes | Yes |
| Windows | — | Yes |
| macOS | — | Yes |
| Linux | — | Yes |
| iOS | Yes | Yes |
| Android | Yes | Yes |
| API | Yes | — |
| Self-hosted | Yes | Yes |
| Plans published | 9 | 1 |
| Spec score · Visual Regression Testing Software | 9.2 (#1) | 8.6 (#4) |
| Spec score · Visual Testing | 9.2 (#1) | 8.7 (#3) |
| License | The public Happo integration library and legacy happo.io repository are released under the MIT License. | The project repository identifies Loki as MIT licensed. |
| Security | Happo says data is encrypted in transit and at rest, conducts regular penetration testing, and treats customer screenshots and related data as confidential with account-level access controls. | The command-line reference documents a `chromeDockerWithoutSeccomp` option, which defaults to false. |
| Storybook integration | Happo provides a Storybook integration for automated component screenshots. | For recent Storybook versions, the documentation says no further integration is needed; older versions may require a React configuration import. |
| Support | Support is founder-led by Henric Persson and Joe Lencioni through documentation, email and repository issues. | The project provides documentation and a GitHub repository for its community and development. |
Plans
Happo
- FreeFree
- FreeFree
- Starter$149 a month
- Starter$149 a month
- Growth$399 a month
- Growth$399 a month
- Pro$749 a month
- Pro$749 a month
- EnterprisePriced on request
In their own words
Happo
Happo checks interface changes with visual and accessibility regression testing. It captures screenshots of component variants in browsers; a snapshot is one variant in one browser, and a run usually occurs once per CI build. Accessibility testing is included on every plan. Framework options include Storybook, Playwright, Cypress, and a generic API. Repository integrations include GitHub, GitHub Enterprise, Bitbucket, Azure DevOps, and GitLab, though GitLab support is experimental. Its CLI detects CI providers such as GitHub Actions, CircleCI, Travis CI, and Azure DevOps. Available browsers vary by plan: the listed options are Chrome, Firefox, Safari, Microsoft Edge, and iOS Safari. The free plan includes 5,000 snapshots per month; once the quota is reached, the account pauses until the next cycle or an upgrade. Paid plans start at $149/mo, with additional snapshots charged on paid tiers. Happo began as a project in 2014, and its commercial product launched in 2017.
Loki
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.