Preparing for Verso and Beyond: Future-Proofing Your Frontend for New Browser Engines
by @designerly.bsky.social on , tagged guest-posts, verso, servo, browsers, browser-engines (share this post, e.g. on Mastodon or on Bluesky)
[Author’s note: During the drafting of this article, the Verso project was discontinued. While the original focus was on preparing for Verso, the insights and strategies discussed remain valuable for future-proofing your frontend development against emerging browser engines and technologies. I hope you find the information useful as you navigate the ever-evolving landscape of web development.]
For years, many frontends could get away with targeting a single dominant engine, with WebKit and Gecko filling smaller niches. Now, new browsers like Verso—based on the Servo web engine—are creating a shift away from the “engine monoculture,” which introduces new compatibility quirks and a larger surface area to test.
As such, you need to write resilient code that prepares for this new era. Take actionable steps today to future-proof your user interface (UI) for tomorrow and whatever comes next.
The New Reality of Browser Engine Diversity
The comeback of alternative engines changes the baseline assumptions that frontend development professionals have been coding against for years. Engine competition means differences in how specifications are implemented, varying levels of feature support, and occasional rendering or JavaScript (JS) behavior quirks.
Verso is a great example of how experimentation on non-Chromium platforms can make user-facing differences. For example, the Servo team prioritized a multi-view support feature, which allows Verso to create two web views currently. That is when you should test multi-view and UI-embedding scenarios. Otherwise, you can turn “works in Chrome” into a risky launch strategy with slight layout changes or missing APIs.
Core Principles for Building a Strong Frontend
The following foundational philosophies serve as design rules for future-proofing a frontend to accommodate engine diversity.
Write Standards-Compliant, Semantic Code
Focus on using HTML, CSS, and JS according to the specifications. These standards are the common ground on which all engine developers build.
Standards-compliant code provides users with a more consistent experience, regardless of the engine. In fact, industry surveys show that 84% of companies that improved customer experience experienced increased revenue, so investing in cross-engine compatibility now is an investment in the business’s future.
Use semantic elements and meaningful ARIA where needed, and avoid engine-specific hacks.
Make Progressive Enhancement the Default
Start with a baseline experience that works everywhere, then layer on enhancements for more capable browsers and engines. This step means shipping a functional HTML starting point, enhancing with CSS where supported, and adding JS behavior progressively, not the other way around.
Additionally, ensuring features fail softly is a useful fallback, but aim to design with progressive enhancements first.
Leverage Feature Detection Over Browsing Sniffing
Instead of guessing capabilities by reading a browser’s name, test for what exists. Feature detection involves designing around whether a capability is available, rather than which browser or engine your users are using. Such measures make your UI resilient to engine differences.
What this looks like in practice is preferring capability-based checks and small, targeted fallbacks. Add polyfills only when a feature gap materially harms the user experience, and design the baseline so it remains fully usable without optional features.
Additionally, consider using lightweight feature detection helpers or incorporating quick manual checks into your process. For instance, verify the baseline layout and key interactions visually in a non-Chromium page.
Strategies and Architectural Patterns
These tactics are patterns you can reuse across components and teams.
1. Use Layout-Agnostic CSS
Favor intrinsic layout tools that adapt to content and container instead of hardcoding styles to a viewport or a particular engine. Use Flexbox and Grid, along with container queries and relative units, so components size and flow based on the content and the space they are placed in.
Design fluid typography and spacing systems so text and UI scale naturally and include simple fallbacks for older engines. For example, you could implement a stacked layout if a container query is unavailable. This method pays off in fewer brittle layout bugs and a UI that behaves sensibly when rendered by an unfamiliar engine.
2. Adopt Component-Based Architectures
Build in small, encapsulated components with clear public interfaces so each piece can be tested and reasoned about independently. Frameworks like React and Vue encourage this approach, but you can apply the same pattern with vanilla code, such as isolating markup, styles, and behavior for a single responsibility.
It is also important to avoid leaking implementation assumptions across components. Component isolation simplifies cross-engine testing, speeds debugging when something breaks, and makes progressive enhancement and server rendering easier to manage.
3. Make Testing and Observability Operational
Treat cross-engine testing as a first-class part of your delivery pipeline. Automate smoke tests for core user flows across multiple engine families and use visual regression checks to detect layout drift.
According to market research, the global cross-browser testing market reached $1.2 billion in 2023 and is projected to grow to $3.8 billion by 2032. Consequently, organizations are investing more in tools and processes to identify cross-engine issues before they reach users.
Next, run a small selection of non-Chromium environments in continuous integration and prioritize tests that assert user-visible behavior. For example, can the user complete the checkout flow?
Then, use feature flags and staged rollouts to limit risk and pair automated checks with user data and monitoring so you know which engine gaps are affecting people. That data should drive your polyfill and workaround priorities.
Future-Proof Your Frontend by Building for the Web
Engine diversity facilitates projects built on alternatives. They show that experimentation can reach real users, so treating “works in Chrome” as sufficient is a risky bet. Utilize the core principles and strategies so you catch regressions early.
Make decisions based on user data and prioritize fixes that impact core user flows. These methods keep your engineering spend honest, helping you deliver a more trustworthy product and a better experience for everyone.
(Frontend Dogma accepts guest posts as long as they aren’t predominantly AI-generated or promotional. Although guest posts are being reviewed, Frontend Dogma cannot and does not vouch for their accuracy, and does not necessarily endorse recommendations made in them.)