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Loki

Open Source

Visual regression testing for Storybook — snapshot every story across browsers and viewports.

Visit websiteGitHub

Pricing

Free / Open source

Type

Automation

Languages

JavaScript

// VERDICT

Reach for Loki when you use Storybook and want free, self-run visual regression against your own baselines. Skip it when you want a managed service with review workflows (Chromatic), AI diffing (Applitools), or you're not on Storybook.

Best for

Open-source visual regression testing for Storybook - capturing and diffing component snapshots locally/CI against baselines, a free self-run alternative to hosted Storybook visual services.

Avoid when

You want a managed cloud service with review workflows (Chromatic), AI diffing (Applitools), or you don't use Storybook.

CI/CD fit

CLI + Storybook · headless/Docker rendering · CI with baselines

Languages

JavaScript

Team fit

Storybook teams wanting free visual testing · Self-hosted CI · Frontend QA

Setup

Medium

Maintenance

Medium

Learning

Intermediate

Licence

Free / Open source

// BEST FOR

  • Free, open-source visual regression for Storybook
  • Snapshotting and diffing component stories
  • Self-run locally and in CI with your baselines
  • Consistent rendering via Docker
  • No per-snapshot cloud cost
  • Catching component visual regressions

// AVOID WHEN

  • You want a managed service with review workflows (Chromatic)
  • AI diffing that suppresses noise is needed (Applitools)
  • You don't use Storybook
  • You don't want to manage baselines
  • False positives from pixel diffs are a concern
  • Minimal setup is the priority

// QUICK START

npm install -D loki
npx loki update     # capture baselines (Docker for consistency)
npx loki test       # diff in CI

// ALTERNATIVES TO CONSIDER

ToolChoose it when
ChromaticYou want a managed Storybook visual service with review workflows.
BackstopJSYou want free visual regression beyond Storybook.
PercyYou want a managed cross-framework visual platform.

// FEATURES

  • Storybook-native — snapshots every story automatically
  • Chrome, Firefox, and iOS Simulator targets
  • Configurable viewports and CSS animation handling
  • Approve/update workflow via CLI
  • Docker support for deterministic rendering
  • Hooks for pre-snapshot setup

// PROS

  • Self-hosted Storybook visual testing for free
  • Component-level coverage with minimal config
  • Good fit for design systems

// CONS

  • Storybook required
  • Slower CI runs at scale than cloud-based alternatives
  • Maintenance pace less active than Chromatic

// EXAMPLE QA WORKFLOW

  1. Add Loki to the Storybook project

  2. Capture reference images (Docker)

  3. Run snapshot diffs in CI

  4. Triage diffs vs noise

  5. Approve and update baselines

  6. Manage baseline storage

// RELATED QA.CODES RESOURCES