ProtoFluid

ProtoFluid is in early-access

Welcome

ProtoFluid delivers an in-document responsive design testing app that manages flexible <iframe> viewports, pop-up windows and even viewport <meta> mimicry.

Try it now — for free

Take ProtoFluid for a spin on this website or download and trial it on one of your projects.

Download

ProtoFluid Core v0.0.9 | 12.8.2026

ProtoFluid Pro

ProtoFluid Pro offers unlimited viewports, fullscreen mode, wake lock and removes the upgrade prompts.

Visit the shop

Gold sponsors

Become a sponsor — or perhaps — a hero?

Enhance your workflow

ProtoFluid accelerates and enhances the responsive design process.

  • Parallel viewports extend your responsive visibility.
  • Reduce cognitive overhead. View multiple breakpoints at once.
  • Spot issues early and avoid rework at the end of a project.

Browser agnostic

ProtoFluid is not limited to a single layout and rendering engine.

It allows you to use the browser, tools and extensions of your choice.

Feature highlights

  • Viewports for watches, phones, tablets and beyond.
  • Extend viewport heights to see more of your work.
  • CSS-only refresh and stylesheet toggles.
  • Color-scheme adjustment.
  • Scroll-to-bottom/top or even by selector.
  • Zoomable viewports. Test large screens on laptops.

Clients and colleagues can far more easily grasp the the work involved when they can see the results.

Silver sponsors

Interested in becoming a sponsor?

Viewport meta mimicry

On mobile devices ProtoFluid lets you intuitively modify the viewport <meta> tag on-the-fly.

One ring phone to rule test them all.

An iPhone and Android phone combo covers a significant amount of potential user devices.

Your phone is a device lab

Viewport meta mimicry can dramatically reduce testing hardware cost.

  • Testing takes place in realistic conditions.
  • Less device switching, charging and updating.
  • Fewer cables!
  • Save electricity and reduce desk clutter.

Private by default

ProtoFluid delivers private responsive testing.

It exists in the context of your project. It does not depend on a server, has zero dependencies and is completely tracker free.

Proudly independent

ProtoFluid is completely independent of big tech.

The ProtoFluid assets are not available via any third party service. Do not trust code hosted on GitHub, NPM or anywhere else.