> ## Documentation Index
> Fetch the complete documentation index at: https://docs.openvisualregression.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction

> Self-hosted, scalable visual regression testing.

OVR captures screenshots from your UI and diffs them against approved baselines. It runs entirely on your own infrastructure: a web dashboard, a worker that captures and diffs snapshots with Playwright, and a CLI that CI pipelines run to upload a build.

## Why OVR?

Unit tests verify behavior, not appearance. A component can pass every test and still ship with broken spacing, a clipped label, or a layout that only breaks at one viewport width.

That gap matters more as more UI code gets written by AI agents. A generated change can compile, pass its tests, and still be visually wrong in a way that's easy to miss in a text-based review. Asking an AI to look at a screenshot and judge whether it looks right helps, but that judgment is non-deterministic and rarely covers every breakpoint and state a change could touch.

Pixel diffing is deterministic: every story, every configured viewport, every time. It won't tell you if a design is good, but it will tell you exactly what changed, and let a reviewer, human or automated, decide if that was intentional.

## How it works

* **No separate test files.** Point the CLI at a `storybook build` output instead of writing and maintaining dedicated visual test files.
* **Review workflow.** Visual diffs that cross the threshold go into a review queue.
* **Git status checks.** Connect a project to your Git provider and OVR posts build/review status as a commit check, so a pull request can gate on it.
* **Bring your own infra.** Postgres, Redis, and any S3-compatible storage. Self-hosted or managed, your call.

## Source and license

OVR is [source-available](https://github.com/open-visual-regression/open-visual-regression/blob/main/LICENSE) under the Elastic License 2.0: free to self-host and modify. The one restriction: you may not offer it to third parties as a hosted or managed service.