Verify that Flash is not used

Flash is dead. Adobe ended support on December 31, 2020. Every major browser blocks it. Any page still using Flash shows a broken embed to every visitor.

If you built your site in Webflow, you almost certainly don't have Flash — Webflow doesn't support it natively. The only way it ends up on a Webflow site is through custom code: a .swf file embedded via an HTML Embed element, or a JavaScript library from before 2015 that includes Flash as a fallback.

Why check anyway: if you're relaunching an older site, migrating from a legacy CMS, or working with inherited code from a previous developer, there's a real chance of leftover Flash references. They won't crash your site — they'll produce broken plugin containers that look unprofessional and signal to Google that the page hasn't been maintained.

How to check: search your Webflow custom code for .swf references. Look in Site Settings → Custom Code, then check any Embed elements on individual pages. If you find a .swf reference, remove it and replace the functionality with an HTML5 alternative — a video embed, animated SVG, or CSS animation depending on what the Flash was doing.

While you're doing this check, audit the rest of your custom code for anything similarly outdated. Old JavaScript libraries added to the site header are worth reviewing. Questions to ask: Is this library still maintained? Is it doing something the modern browser handles natively? Is it loading on every page when it's only needed on one?

Outdated scripts create two problems. First, they add weight to every page load — scripts run even when they do nothing useful, and that load time shows up in your Core Web Vitals. Second, old libraries often conflict with newer code, creating console errors that are difficult to trace.

Webflow's Site Settings → Custom Code is the main place to audit this. If you've been adding scripts over time — analytics, chat widgets, third-party integrations — this is a good moment to remove anything that's no longer in use. Each script you keep is a cost you pay on every page load.

Flash is the most obvious dead technology to remove before going live. The broader habit of keeping custom code clean is what matters long-term.