Every mobile project starts with the same question: how many codebases are we going to maintain? Build separately for iOS and Android and you write, test and fix everything twice. Reach for a cross-platform wrapper and you often trade native feel for speed. Kotlin Multiplatform (KMP) is how we avoid both traps, and it is our default for new mobile work.
What KMP actually shares
The important thing to understand about KMP is what it shares and what it does not. Your business logic, networking, data models, storage and validation live in one shared Kotlin module. That is the code that is expensive to write, easy to get subtly wrong, and painful to keep in sync across two platforms. KMP lets you write it once and compile it into both apps.
The user interface can be shared too, with Compose Multiplatform, or left fully native per platform where the experience demands it. That flexibility matters. It means you are never forced to choose between code reuse and a screen that feels exactly right on the device.
KMP is not a webview in a trench coat. The apps it produces are genuinely native, because they are.
Why it wins on cost, not just elegance
The business case is simple. A shared core means a bug is fixed once, a feature is built once, and the two apps cannot drift apart because they run the same logic. Over the life of a product, that is where the real savings are: not in the first build, but in the years of maintenance after it.
- One team and one language across the stack, rather than separate iOS and Android specialists
- Fewer places for the same bug to hide, and fewer regressions from keeping platforms in step
- Native performance and access to platform APIs, with no bridge to fall through
- A gradual path in: you can adopt KMP module by module in an existing app
Where we would not use it
We are not dogmatic. If you are building a single-platform app with no plans to expand, the shared-code argument weakens. If your team is deeply invested in another stack and the app is simple, forcing KMP in can cost more than it saves. Part of an honest recommendation is knowing when the smart move is something else, and we will tell you when that is the case.
But for most teams building for both iOS and Android and planning to maintain the result for years, KMP is the modern answer. It is how we build our own apps, and it is why we maintain a family of open-source KMP libraries the community ships with too.