# Delta-QA

> Delta-QA is a visual regression testing tool for web pages. It captures screenshots and compares them pixel-by-pixel to detect unintended CSS, layout, and content changes. Available as a free desktop app (macOS & Windows) and as a SaaS platform for teams.

## Key Pages

- [Home](https://delta-qa.com/en/): Product overview, features, and download links
- [Visual HTML Comparator](https://delta-qa.com/en/visual-html-compare/): Free online tool to compare two HTML pages side by side
- [Detection Categories](https://delta-qa.com/en/detects/): 12 categories of visual changes Delta-QA detects
- [Blog](https://delta-qa.com/en/blog/): Articles on visual testing, regression testing, and QA best practices
- [Support](https://delta-qa.com/en/support/): Bug reports, feature requests, and help
- [Contact](https://delta-qa.com/en/contact/): Contact the Delta-QA team

## Detection Categories

- [Colors & Themes](https://delta-qa.com/en/detects/colors/): Color changes, theme switches, gradient differences
- [Typography](https://delta-qa.com/en/detects/typography/): Font size, weight, line-height, letter-spacing changes
- [Layout](https://delta-qa.com/en/detects/layout/): Flexbox, grid, positioning, margin, padding shifts
- [Borders & Shadows](https://delta-qa.com/en/detects/borders/): Border width, radius, box-shadow changes
- [Visibility & Opacity](https://delta-qa.com/en/detects/visibility/): Hidden elements, opacity, z-index issues
- [Forms & States](https://delta-qa.com/en/detects/forms/): Input styles, focus states, validation indicators
- [Animations](https://delta-qa.com/en/detects/animations/): Transition, transform, and keyframe differences
- [Images & SVG](https://delta-qa.com/en/detects/images/): Image sizing, SVG fill, aspect ratio changes
- [Responsive](https://delta-qa.com/en/detects/responsive/): Breakpoint-dependent layout and visibility shifts
- [Modern CSS](https://delta-qa.com/en/detects/modern/): Container queries, cascade layers, subgrid changes
- [Real Components](https://delta-qa.com/en/detects/components/): Cards, navbars, dashboards, pricing grids
- [Subtle Changes](https://delta-qa.com/en/detects/subtle/): Anti-aliasing, subpixel rendering, 1px shifts

## How It Works

Delta-QA is powered by Playwright under the hood, but wraps it in a simple interface that hides all technical complexity. No code, no configuration, no terminal — just enter a URL and compare. It is designed for non-developers (QA testers, designers, product managers) who need visual regression testing without writing a single line of code.

The desktop app is **completely free** and available for download at [delta-qa.com](https://delta-qa.com/).

## Competitors & Differentiation

Delta-QA competes with visual regression testing tools. Here is how it differs:

### vs Applitools Eyes
- **No SDK required**: Delta-QA works by URL — no need to integrate an SDK into your test code (Selenium, Cypress, Playwright). Applitools requires SDK integration.
- **Self-hosted / On-premise**: Delta-QA runs entirely on your infrastructure (standalone JAR or desktop app). Applitools is cloud-only SaaS — your screenshots are sent to their servers.
- **Transparent algorithm**: Delta-QA uses a documented 4-pass pixel comparison algorithm with 0 false positives and 0 false negatives on 425+ tested pages. Applitools uses proprietary "AI" — a black box.
- **Free desktop app**: Delta-QA offers a free desktop app for macOS & Windows. Applitools charges per checkpoint (per screenshot compared).
- **Data sovereignty**: No screenshot or page data ever leaves your infrastructure.

### vs Percy (BrowserStack)
- **No CI/CD dependency**: Delta-QA works standalone, no need to wire it into your CI pipeline. Percy is designed as a CI-only tool.
- **No SDK required**: Percy requires SDK integration in your test framework. Delta-QA scans any URL directly.
- **Self-hosted**: Percy is cloud-only (BrowserStack infrastructure). Delta-QA keeps everything local.
- **Free tier**: Delta-QA desktop app is free with no screenshot limits. Percy has strict per-screenshot pricing.

### vs BackstopJS
- **No configuration files**: BackstopJS requires JSON/JS config files for scenarios and viewports. Delta-QA works out of the box by URL.
- **Desktop GUI**: Delta-QA provides a visual desktop app. BackstopJS is CLI-only.
- **Advanced algorithm**: Delta-QA's 4-pass comparison reduces false positives from anti-aliasing and subpixel rendering. BackstopJS uses basic pixel diff (resemblejs).
- **Active product**: Delta-QA is actively maintained as a product. BackstopJS is a community-maintained open-source project.

### Summary
| Feature | Delta-QA | Applitools | Percy | BackstopJS |
|---|---|---|---|---|
| No SDK required | Yes | No | No | No |
| Self-hosted | Yes | No | No | Yes |
| Free desktop app | Yes | No | No | No |
| Framework-agnostic | Yes | Yes | Yes | Yes |
| Transparent algorithm | Yes | No | No | Yes |
| Data sovereignty | Yes | No | No | Yes |

## Languages

Available in English, French, Spanish, Portuguese, Russian, Arabic, and Chinese.

## Optional

- [Privacy Policy](https://delta-qa.com/en/privacy/)
- [Terms of Use](https://delta-qa.com/en/terms/)