Mobile and TV Are the Same Design, Different Language

A shared codebase gets you further on connected TV than people expect, right up until it doesn't. The visuals carry over almost entirely. The interaction model does not carry over at all. That gap is where TV projects quietly blow their timeline.

The design looks like a rerun

Take a mobile screen and put it on a TV and it'll look about 90% right immediately. Same layout logic, same visual hierarchy, same component thinking you'd use on a tablet or desktop. Cards, rows, grids, all of it translates. If you're judging a TV app screenshot next to a mobile screenshot, you'd assume they came from the same design system, because they usually did.

That similarity is exactly what gets teams in trouble. It looks close enough that people assume the build will be close too.

The interaction model is a different animal entirely

Here's the part that doesn't show up in a screenshot: nobody is touching this screen. There's no finger, no cursor, no hover state to lean on. There's a remote with a D pad and a handful of buttons, and that's it.

On mobile and web, navigation is direct. You see the button, you tap the button, done. On TV, navigation is spatial. The user is moving a focus indicator around the screen one direction at a time, and your app has to know, at every single point, what's above, below, left, and right of whatever is currently focused. You're not designing taps anymore. You're designing a graph.

A few things that just disappear when you move to TV:

• Swipe gestures. Gone completely. No swipe to dismiss, no swipe between tabs, none of it.
• Precise tapping on a small target. A remote can't aim at a 32px icon the way a thumb can.
• Scrolling by feel. Scrolling on TV is usually focus jumping row by row, not a smooth drag.

And the thing that replaces all of it is proximity. Everything is about what's next to what. On mobile, a user can jump straight to any CTA on the screen in one motion. On TV, they have to travel there, one focusable element at a time, in whatever order your focus map defines. If that map is wrong, the user gets stuck, or worse, focus just vanishes and they're mashing the remote wondering if the app froze.

That's the real tradeoff. You're not losing capability moving from mobile to TV. You're trading a coordinate system for a graph, and every interactive element needs an explicit answer for "what do I do when the user presses up."

Same design. Different physics.

What you actually keep in a shared codebase

React Native style architecture can genuinely share a huge amount across mobile, Apple TV, Android TV, Fire TV, and similar platforms. Business logic, data layer, a lot of your component structure, even a good chunk of your styling. That's real and it's not a sales pitch, I've shipped that exact setup.

What you don't get for free is the navigation and focus layer. That has to be built for TV specifically, on top of the shared foundation, not inherited from the mobile version. Budget for it as its own thing, because it is one.

Roku is not invited to this shared codebase

Everything above assumes you're on platforms that speak the same technology family your mobile app already speaks. Roku does not. Roku runs on its own language and its own framework, built and maintained entirely inside Roku's own world. There's no bridge, no wrapper, no clever trick that lets your React Native code just also run there.

If Roku is on your platform list, that's not an extra checkbox on an existing project. That's a second, separate build, with its own codebase, its own tooling, and its own development process from day one. Plan for it like you're building a second app, because you are.