We support the current and previous major releases of Google Chrome, Apple Safari, Mozilla Firefox, and Microsoft Edge across desktop and mobile devices. Legacy platforms, unsupported operating systems, and retired browsers such as Internet Explorer are not supported in standard production builds.
Supported browser matrix
Our Technology department maintains baseline support for standard builds across modern rendering engines (Blink, WebKit, and Gecko). Support covers:
- Google Chrome: Current stable release and the immediately preceding version (macOS, Windows, Android, iOS).
- Apple Safari: Current stable release and one version prior (macOS, iOS, iPadOS).
- Microsoft Edge: Current stable release and one version prior (Windows, macOS).
- Mozilla Firefox: Current stable release and the Extended Support Release (ESR) track (Windows, macOS, Linux).
Standard builds use modern CSS Grid, Flexbox, native JavaScript (ES2020+), and contemporary media formats including WebP and SVG. We do not inject heavy polyfills or write fallbacks for deprecated browser versions unless explicitly scoped and agreed in the bespoke project brief.
Testing sequence and responsibilities
Cross-browser verification follows a structured sequence within the development lifecycle:
1. Local engineering checks: Developers test interface components in Chromium and WebKit environments throughout active sprints. 2. Staging deployment: The Technology department deploys code to a private staging environment and runs testing across our standard device matrix (macOS, Windows, iOS, and Android). 3. Client QA review: You receive staging access to inspect your site on your organisation's standard hardware and browsers. Testing should occur during our core operating hours (Monday to Thursday, 09:00-17:00 GMT). 4. Bug remediation: Defects identified in supported browsers are logged, categorised, and resolved prior to deployment. If you find visual or functional flaws, submit the report through the Ask Xylo chat on this portal. 5. Sign-off: You provide written acceptance confirming the build operates as intended across your required environments.
Custom and enterprise environments
If your organisation or target audience relies on legacy enterprise builds, locked corporate desktop images, or specific in-app web views (such as embedded Instagram or LinkedIn browsers), you must notify us before project kick-off.
Supporting non-standard environments requires dedicated polyfills, alternative CSS architectures, and manual regression passes. This work falls outside fixed packages. If requested, our Technology team evaluates the technical constraints and issues a bespoke quote within 48 hours of receiving your exact environment specifications. Deposits are non-refundable once your production slot is held. Before work begins, sums not yet earned are refunded pro rata; after work begins, completed work and booked time are charged. Defects are fixed free of charge within the acceptance window. The full terms are on the Refund Policy page of the main site.
Failure cases and visual variances
Web browsers do not render code identically. Minor visual differences across platforms are normal and do not constitute bugs:
- Font rendering: Type weights render slightly heavier on macOS and iOS due to Core Text smoothing, whereas Windows ClearType renders thinner, sharper edges.
- Form controls: Native input elements, select menus, date pickers, and scrollbars follow operating system UI guidelines unless custom components are built.
- Sub-pixel rounding: Small layout shifts (1 pixel or less) can happen between Blink and Gecko rendering engines at non-standard display scaling factors (e.g., 125% or 150% display scaling on Windows laptops).
A defect is recognised when an element fails to function, breaks layout boundaries, obscures critical content, or prevents user completion of a journey within a supported browser.
When reporting rendering issues via Ask Xylo chat, you must provide: - The exact browser version (found via the browser's 'About' dialog). - Operating system and version. - Device screen resolution and scaling setting. - A full-screen screenshot showing the viewport and browser chrome.
Our team investigates and replies within our standard 24-hour first-reply target during studio working days.
Pre-launch browser checklist
Run this verification before approving final deployment:
- [ ] Confirm layout renders cleanly on the current version of Google Chrome.
- [ ] Inspect pages in Apple Safari (both desktop and mobile iOS).
- [ ] Verify functionality in Microsoft Edge and Mozilla Firefox.
- [ ] Check forms, inputs, and interactive states on mobile touchscreens.
- [ ] Test critical journeys at standard desktop zoom (100%) and native mobile resolution.
- [ ] Document and submit genuine rendering bugs via Ask Xylo chat before sign-off.