Percy

Percy captures web page screenshots during CI runs and shows pixel-level visual diffs for human review — making visual regressions visible in pull requests before deployment. Integration pattern: install Percy SDK for your test framework, set PERCY_TOKEN, call percySnapshot() in tests to capture pages. Percy uploads snapshots to its platform, renders across configured browsers/viewports, and creates a build with a diff for review. Part of BrowserStack since 2021. For agents in QA automation pipelines, Percy adds visual regression gating to CI without requiring specialized visual testing knowledge. Confidence is docs-derived.

REST API at percy.io/api/v1. Resources: builds, snapshots, comparisons. GET /api/v1/projects/{projectId}/builds lists builds (status, total_snapshots, total_comparisons). GET /api/v1/builds/{id}/snapshots lists snapshots in a build with diff status (approved/changes_requested/unreviewed). POST /api/v1/builds/{id}/approve approves all unreviewed changes in a build. Primary integration via SDK (percy-cli, @percy/selenium, @percy/cypress, @percy/playwright): snapshots captured and uploaded automatically during test execution. Token (PERCY_TOKEN) identifies the project.

PERCY_TOKEN environment variable for SDK authentication. Project token from Percy settings. REST API: Authorization: Token {token} header using the same project token. Project-scoped access; each Percy project has its own token. No OAuth2; token is the single auth mechanism. Team access managed via Percy organization settings (owner, member, reviewer roles). HTTPS enforced. Token rotation via Percy project settings.

SDK connectivity errors surface in CLI output. REST API: standard HTTP status codes. 401 for invalid token, 404 for missing build/snapshot. Build status: pending (upload in progress), processing (rendering), finished (diff ready). Diff classification: no_diffs (no visual change), diffs (changes detected requiring review). CI status integration: Percy sets GitHub/GitLab commit status to pending until build is approved. Percy SaaS uptime (now BrowserStack infrastructure). Rate limits documented per plan tier.

browserstack.com/docs/percy provides SDK integration guides for Selenium, Cypress, Playwright, Storybook, WebdriverIO, and more. REST API reference available. Getting started requires a Percy account (free plan with limited screenshots/month). Percy CLI for framework-agnostic screenshot capture (snapshots from static HTML or URL). Integration with GitHub, GitLab, Bitbucket for PR status checks. Community support via BrowserStack Community.