Advice for photosensitive epilepsy amounts to avoiding the trigger, which fails the moment something autoplays. FlashFilter sits between the desktop and the display, analyses every frame, and damps the flash in place — leaving the rest of the picture alone.
The existing options are all bad in the same way. Browser extensions only cover the browser. Reduced-motion settings only cover apps that respect them. A dark overlay or a colour tint dims the flash by dimming everything, which is why people stop using them. And none of it helps with a game, a video call, or a clip somebody sends you.
FlashFilter takes the other approach: it runs as a GPU compositing layer between your desktop and your display, so it sees the finished frame regardless of which application produced it. It analyses each one for flashing and sudden brightness spikes and, depending on the setting, dampens or removes them in real time. The key claim — and the one that makes it worth installing rather than reading about — is that nothing else changes. No overlay, no tint. The flash is what gets smoothed; the rest of the picture is left as it was.
It runs on Windows, Mac and Linux, using each platform’s native graphics stack: DirectX 12, Metal, Vulkan. Linux support is limited to Wayland compositors. Because the work happens on the GPU within a fraction of a frame, the developer’s position is that it will not cost you frame rate or battery, though the site is upfront that the cost varies with hardware and that the different filtering algorithms trade performance against quality. Everything happens locally — frames never leave the machine, and the only account detail is the sign-in carrying your licence.
Two things to know before you get attached. It is free right now because it is a public beta that opened on 30 June and runs free through 25 August, no card required; after that it moves to a subscription, and the site does not yet say what that costs. And the developer, Idrith, states the limitation plainly on the page: FlashFilter is not a medical device and is not a substitute for medical advice — it reduces flashing that may trigger symptoms, but it cannot guarantee that all of it is removed.
That disclaimer is the reason to trust the rest of it. This is a category where overpromising is cheap and the consequences land on somebody having a seizure. A tool that says “we make this materially safer, we do not make it safe” is describing what software can actually do about a problem the whole desktop stack has spent thirty years ignoring.