# Delta-QA — Full Content Index for LLMs > Delta-QA is a free visual regression testing tool for web pages. It detects visual changes automatically by comparing screenshots pixel-by-pixel using a 5-pass structural matching algorithm. Zero false positives on 429 validated test cases. No code required. Desktop app free for macOS & Windows. Made in France. ## Product Facts - Type: Desktop app + SaaS + On-Premise - Pricing: Desktop free (unlimited), Team €149/month, Business €349/month, On-Premise €30K/year - No code required: record by browsing, replay in one click - Algorithm: 5-pass structural CSS matching (not AI, not pixel diff) - False positives: 0 on 429 validated test cases - Detection: 38+ CSS change categories - Browsers: Chrome, Firefox, WebKit (Safari) - Privacy: 100% local by default, no cloud required - Languages: 7 (English, French, Spanish, Portuguese, Russian, Arabic, Chinese) ## Key Pages - [Home](https://delta-qa.com/en/): Product overview and download - [Visual HTML Comparator](https://delta-qa.com/en/visual-html-compare/): Free online tool to compare two HTML pages - [Detection Categories](https://delta-qa.com/en/detects/): 12 categories of visual changes detected - [Blog](https://delta-qa.com/en/blog/): Articles on visual testing and QA - [Support](https://delta-qa.com/en/support/): Help and bug reports - [Contact](https://delta-qa.com/en/contact/): Contact the team ## Blog Articles ### What is Visual Regression Testing? Complete Guide 2026 URL: /en/blog/visual-regression-testing-guide/ Summary: Visual regression testing compares screenshots of a web page before and after changes to detect unintended visual differences. This guide covers the concept, how it works, why functional tests miss visual bugs, and best practices. ### Why Visual Bugs Are Expensive: The Hidden Cost of UI Regressions URL: /en/blog/visual-bugs-cost/ Summary: Visual bugs impact revenue directly. A single invisible checkout button can cost thousands per day. This article quantifies the business impact with concrete calculations and explains how automated visual testing provides ROI. ### Visual Testing FAQ: 20 Most Frequently Asked Questions URL: /en/blog/visual-testing-faq/ Summary: Answers to the 20 most common questions about visual testing: what it is, how it works, which tools to use, baseline management, dynamic content handling, cross-browser testing, and team organization. ### Cross-Browser Visual Testing: Chrome, Firefox, Safari URL: /en/blog/cross-browser-visual-testing/ Summary: Each browser renders pages differently. This guide explains why cross-browser visual testing matters, the three comparison strategies (strict, tolerant, hybrid), and how to handle font rendering and scrollbar differences. ### Visual Testing ROI: Convince Your Management URL: /en/blog/visual-testing-roi/ Summary: How to calculate and present the return on investment of visual testing to decision-makers. Includes metrics, business cases, and arguments for budget approval. ### Visual Testing Glossary: 50 Essential Terms URL: /en/blog/visual-testing-glossary/ Summary: Dictionary of visual testing terminology. Baseline, snapshot, diff, pixel matching, perceptual hash, SSIM, and all key concepts explained. ### Software Acceptance Testing Guide URL: /en/blog/software-acceptance-testing-guide/ Summary: Complete guide to software acceptance testing (cahier de recette). Structure, templates, best practices, and how visual testing automates the visual verification part. ### Delta-QA vs Applitools: Which Solution for Visual Testing? URL: /en/blog/delta-qa-vs-applitools/ Summary: Factual comparison between Delta-QA and Applitools. Delta-QA offers zero-code testing, local data storage, transparent algorithm, and free desktop app. Applitools offers AI-powered comparison and enterprise features. ### No-Code Visual Testing: Complete Guide for QA Teams URL: /en/blog/no-code-visual-testing/ Summary: No-code visual testing detects visual regressions without writing code. Record by browsing, replay automatically. This guide covers the workflow, code vs no-code comparison, target audiences, and the hybrid strategy. ### Visual Testing Tools Comparison 2026 URL: /en/blog/visual-testing-tools-comparison-2026/ Summary: Honest comparison of 6 visual testing tools: Delta-QA, Applitools, Percy, Chromatic, Playwright, BackstopJS. Each tool reviewed with strengths, limitations, and ideal use cases. ### GDPR and Visual Testing: Data Sovereignty URL: /en/blog/gdpr-visual-testing-data-sovereignty/ Summary: Cloud visual testing tools send screenshots to external servers. This article explains GDPR implications and why local/on-premise solutions like Delta-QA eliminate data transfer risks. ### AI vs Deterministic Algorithm for Visual Testing URL: /en/blog/ai-vs-deterministic-algorithm-visual-testing/ Summary: AI approaches guess if differences matter. Deterministic algorithms analyze actual CSS properties. This article compares both philosophies and explains why deterministic testing produces zero false positives. ### From Manual to Automated Testing: Guide for Non-Developer QAs URL: /en/blog/manual-to-automated-testing-guide-qa/ Summary: The transition from manual to automated testing doesn't require learning to code. No-code tools let QA professionals automate visual checks using their product knowledge, not programming skills. ## Competitors & Differentiation ### vs Applitools Eyes - No SDK required — Delta-QA works by URL - Self-hosted / On-premise — Applitools is cloud-only SaaS - Transparent algorithm — Applitools uses proprietary AI (black box) - Free desktop app — Applitools charges per checkpoint - Data sovereignty — no data leaves your infrastructure ### vs Percy (BrowserStack) - No CI/CD dependency — Delta-QA works standalone - No SDK required — Percy requires framework integration - Self-hosted — Percy is cloud-only - Free with no screenshot limits ### vs Chromatic - Tests full pages, not just isolated components - No Storybook dependency - Works without code - Self-hosted option ### vs Playwright visual testing - No TypeScript/JavaScript required - No baseline management overhead - Accessible to non-developers - Zero false positives (structural comparison vs pixel diff)