SnapDrift

SnapDrift captures full-page application frames, compares them against a known baseline, and reports drift directly in GitHub Actions.

SnapDrift is ready to integrate from public GitHub releases. Workflow examples below use the first public tag for readability; security-conscious consumers can pin the resolved commit SHA instead.

What SnapDrift handles

• Baseline capture on main
• Pull request drift detection against the latest successful baseline
• Route scoping from changed files
• PR report upserts
• Drift enforcement through diff.mode

You keep ownership of checkout, build, startup, readiness, and teardown. SnapDrift takes over once the app is reachable.

Quickstart

1. Add .github/snapdrift.json to your repo:

{
  "baselineArtifactName": "my-app-snapdrift-baseline",
  "workingDirectory": ".",
  "baseUrl": "http://127.0.0.1:8080",
  "resultsFile": "qa-artifacts/snapdrift/baseline/current/results.json",
  "manifestFile": "qa-artifacts/snapdrift/baseline/current/manifest.json",
  "screenshotsRoot": "qa-artifacts/snapdrift/baseline/current",
  "routes": [
    { "id": "home-desktop", "path": "/", "viewport": "desktop" },
    { "id": "home-mobile", "path": "/", "viewport": "mobile" }
  ],
  "diff": { "threshold": 0.01, "mode": "report-only" }
}

2. Publish a baseline on push to main:

- name: SnapDrift Baseline
  uses: ranacseruet/snapdrift/actions/baseline@v0.1.0
  with:
    repo-config-path: .github/snapdrift.json

3. Run SnapDrift on pull requests:

- name: SnapDrift Report
  uses: ranacseruet/snapdrift/actions/pr-diff@v0.1.0
  with:
    github-token: ${{ secrets.GITHUB_TOKEN }}
    repo-config-path: .github/snapdrift.json

That is the full integration. See the Integration Guide for workflow examples, permissions, compatibility notes, and advanced overrides.

Local CLI

SnapDrift ships a snapdrift CLI for running captures and diffs locally against a running app — no GitHub Actions required. Use it during development to validate UI changes before pushing.

# Capture a baseline
snapdrift capture

# Compare against it after making UI changes
snapdrift diff --open

See the Local CLI guide for installation, all flags, directory layout, and examples.

Drift modes

Start with report-only while baselines settle. Move to fail-on-changes or stricter modes once the signal is stable.

Mode	Stops the run when
report-only	Never
fail-on-changes	Any capture exceeds threshold
fail-on-incomplete	Captures are missing, dimensions shift, or comparison errors occur
strict	Any drift signal or incomplete comparison appears

Current constraints

• Ubuntu runners only
• Full-page capture only
• Fixed viewport presets: desktop (1440×900) and mobile (390×844)
• One global diff.threshold
• Dimension shifts are reported separately from pixel drift

Docs

• Integration Guide
• Local CLI
• Contracts
• Changelog
• Contributing
• License