Happo vs Percy

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.

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.