Browser Compatibility Testing Matrix: How to Build One

A browser compatibility testing matrix is a simple table that lists which browser-OS combinations your website or app must support, and what level of testing each one gets. It turns vague promises like “works in all browsers” into a concrete checklist your team can follow. Before you start, you need a clear idea of your target audience (from analytics or client requirements), a list of the browsers and devices they actually use, and a shared place to store the matrix (a spreadsheet, wiki page, or project management tool works fine).

What You’ll Need

• Access to your site or app’s analytics (Google Analytics, Plausible, or similar) to see real visitor browser and OS data.
• A spreadsheet tool (Excel, Google Sheets) or a document/wiki for the matrix itself.
• A list of your key user flows or pages that need testing (e.g., login, checkout, homepage).
• Optional but helpful: access to a device lab, browser testing service (BrowserStack, Sauce Labs), or local virtual machines.

Step-by-Step

1. Gather real browser usage data. Open your analytics and look at the last 1-3 months. Note the browser, version, operating system, and device type (mobile, tablet, desktop) for your top sessions. Filter out bots and internal traffic if possible.
2. Decide on your support tier. Not every browser deserves the same effort. Create three tiers: Tier 1 (full, primary support – test every feature), Tier 2 (should work, test main flows only), and Tier 3 (best-effort – no dedicated testing unless something breaks). Your analytics will tell you which browsers belong in which tier.
3. Define your browser-OS combinations. For each tier, list the exact browser and OS pairs you’ll test. For example: Chrome 120 on Windows 11, Safari 17 on macOS Sonoma, Chrome 120 on Android 14, Safari 17 on iOS 17. Include the most recent two major versions of each browser if your analytics show they matter.
4. Add a column for device type. For each browser-OS row, specify whether you test on desktop, mobile, or both. Mobile testing should use real devices or accurate emulators, not just resizing a desktop window.
5. List your critical user flows. Write down the 5-10 most important actions users take on your site: sign up, log in, search, add to cart, checkout, submit a form, etc. These become the rows or columns of your matrix.
6. Create the matrix table. In your spreadsheet, make rows for each browser-OS combination and columns for each user flow (or vice versa). Add a status column for each cell: Pass, Fail, Not Tested, or N/A.
7. Set a testing schedule. Decide how often you’ll run tests. For a live site, a good baseline is once per release cycle or at least monthly. For a new feature, test it before launch. Note the date of the last test in the matrix.
8. Assign owners. Put a person’s name next to each browser-OS row or each flow. This makes it clear who is responsible for testing and updating the status.
9. Fill in the matrix as you test. When you run a test, record the result immediately. If a test fails, add a note with the issue and a link to the bug tracker ticket.
10. Review and update regularly. Browsers update constantly. At least once a quarter, re-check your analytics and adjust the matrix: remove browsers that have dropped off, add new ones, and re-tier as needed.

Common Mistakes

• Including too many browsers. Trying to test every version of every browser will eat your time. Focus on the ones your analytics say matter.
• Ignoring mobile browsers. Safari on iOS and Chrome on Android are different from their desktop counterparts. Test on actual mobile devices or accurate emulators.
• Testing only the homepage. A site can look fine on the homepage but break on the checkout page. Always include key flows beyond the landing page.
• Not updating the matrix. A matrix that’s six months old is worse than none because it gives a false sense of coverage.
• Using “works in my browser” as a standard. Your personal browser is not representative. Stick to the matrix.

Tips

• Start small. If you have limited time, test only your Tier 1 browsers and your top 3 flows. Expand later.
• Use automation where possible. Tools like Selenium or Playwright can run smoke tests across browsers, but you’ll still need manual testing for visual and interaction issues.
• Keep the matrix in a shared, versioned location. Google Sheets or a wiki page with a change log works well.
• Add a column for “Notes” so testers can record quirks, workarounds, or known issues without cluttering the status cell.
• When a new browser version is released, add it to your matrix as “Not Tested” rather than assuming it works.

Troubleshooting

If you don’t have analytics data: Use your client’s requirements, or if it’s a public site, look at industry stats (like StatCounter’s global browser share) as a starting point. Be clear that this is an assumption and will need updating.

If a browser is not available to you: You can’t install Safari on Windows, and you might not own an iPhone. Use a cloud testing service (BrowserStack, Sauce Labs, LambdaTest) or a local virtual machine with the OS. For iOS, you can use the simulator on a Mac.

If tests keep failing in one browser: Don’t just mark it as fail and move on. Investigate the root cause – it might be a CSS prefix, a JavaScript API not supported, or a rendering quirk. Fix the code, then retest. If it’s a known limitation, document it and decide if it’s acceptable.

If the matrix becomes too large: Revisit your tiers. Move less important browsers to Tier 3, or reduce the number of flows tested for Tier 2. Remember that a smaller, regularly updated matrix is more useful than a huge, ignored one.

If you can’t keep up with browser updates: Automate your smoke tests. At minimum, run a quick manual check of your top flows in the most recent versions of Chrome, Safari, Firefox, and Edge. You don’t need to test every minor version.

Frequently Asked Questions

How many browsers should I include?

There’s no magic number, but a common starting point is 5-10 combinations: the latest two versions of Chrome, Safari, Firefox, and Edge on desktop, plus Safari on iOS and Chrome on Android. Adjust based on your analytics.

What’s the difference between Tier 1 and Tier 2?

Tier 1 means you test every feature and flow before release. Tier 2 means you test only the critical user flows, and you fix issues if they’re quick, but you don’t block a release for minor visual glitches.

Should I test on real devices or emulators?

Real devices are best for mobile, especially for touch interactions and performance. Emulators are fine for initial checks, but they don’t catch everything (e.g., screen size, memory constraints). Use a mix if possible.

How often should I update the matrix?

At least quarterly, or whenever you add a new feature or change your target audience. Also update it when a major browser version is released.

Can I skip testing older browsers like IE11?

Only if your analytics show that IE11 users make up a negligible share of traffic (typically under 1-2%). If you must support it, keep it in Tier 2 or 3 and test only the main flows.

What should I do when a test fails?

Record the failure in the matrix with a screenshot or description, create a bug ticket, and fix the issue. After fixing, retest and update the status. If the issue is a known browser bug, document it and decide if a workaround is needed.

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