Every software engineer is familiar with the concepts of imperative and declarative paradigms, but a quick recap never hurts.

Imperative programming is a foundational approach where developers had to describe and define each step in order to achieve the desired application state. While the paradigm is still the backbone of most core application logic, imperative UI development was the standard. This often leads to more complex, error-prone state management in large, highly interactive applications.

On the other hand, with declarative programming, developers describe what results they want to achieve, rather than how the computer will achieve it. Instead of focusing on detailed steps, they describe the desired state of the application, and the framework handles the transition. The result is simpler code, faster development and fewer state-related bugs.

• Imperative paradigm: Step-by-step instructions to achieve the desired outcome (how).

• Declarative paradigm: We describe the desired outcome, and the framework determines the steps to achieve it (what).

Imperative UI means using code to manually manipulate UI elements, update properties, and explicitly manage layout and animations in response to user actions.

Declarative UI (e.g., SwiftUI, Jetpack Compose) means you define the application states, and then describe the entire UI as a pure function of that state. When the state changes, the framework automatically and efficiently redraws the UI to match the new definition.

We started with XML layouts, Storyboards relying on manual state management to update those view. We have now moved fully to frameworks that allow us to describe what the UI should look like for any given state.

The Tipping Point in 2025

For years, the debate was theoretical, but in 2025 we've reached a tipping point. Native declarative frameworks like SwiftUI and Jetpack Compose are now mature and considered best practice. Cross-platform solutions like Flutter have proven their performance capabilities. This is no longer a question of 'if' you should adopt a declarative UI model, but 'which one' is the right strategic bet for your team and product.

Declarative UI isn’t new, but it took some time to seep into the mobile world. Even though Facebook’s React Native was at the forefront of this it took several years for others to catch up.

Here’s a high-level analysis of the four leading mobile frameworks.

React Native (The Veteran):

• Overview: Facebook's (now Meta's) open-source framework was a pioneer in bringing the declarative model to mobile and remains one of the most popular solutions. It was released on March, 2015.
• Strengths: Huge developer community, massive ecosystem of libraries, and allows for significant code sharing with web teams who also use React. "Fast Refresh" provides an excellent developer experience.
• Weaknesses: Performance can be a concern for highly complex animations or processing-intensive tasks due to its reliance on a JavaScript "bridge." Upgrades can sometimes be complex, and it doesn't always have day-one support for the latest native OS features.

Flutter (The True Cross-Platform Play):

• Overview: Build for iOS, Android, Web, and Desktop from a single codebase. Released on December 4, 2018.
• Strengths: Maximum code reuse, incredibly fast time-to-market, and a unified team structure.
• Weaknesses: It doesn't use native UI components, which can sometimes be a pro or con. Requires learning the Dart language.

SwiftUI (Apple's Future):

• Overview: The premier, official way to build apps for the entire Apple ecosystem. Released on June 3, 2019, as announced by Apple at WWDC19.
• Strengths: Unmatched native performance, deep OS integration (widgets, live activities), and the most future-proof choice for iOS/macOS.
• Weaknesses: Apple-only, which means you still need a separate solution for Android.

Jetpack Compose (The Modern Android):

• Overview: Google's powerful and official answer to SwiftUI for the Android world. Released on July, 2021.
• Strengths: Fully interoperable with existing Android apps, great developer tooling, and pairs perfectly with Kotlin Multiplatform (KMP) for shared business logic.
• Weaknesses: Primarily Android-focused.

The CTO's Decision Matrix

I bet the next question on your mind is - allright, there are too many options, how do I choose? - let’s help with that. The major factors in your decision comes down to business goals and team structure.

Is the absolute best native performance and seamless OS integration our top priority?

Bet on the native platforms. Empower your iOS and Android teams to use SwiftUI and Jetpack Compose.

Is speed-to-market on both platforms with a single team the most critical business goal?

Flutter is likely your strongest choice. It's designed for maximum efficiency and code reuse.

Do we have a strong web development team skilled in React?

React Native is a powerful option. It leverages existing skills, allowing your web team to contribute to mobile development and share logic.

Do we want native performance but still need to share logic efficiently?

The KMP + SwiftUI/Compose combination is the modern, powerful solution for this exact problem.

The Decision Is About Your Team and Your Goal

There’s no one size fits all framework nor solution in tech, the best is the one that aligns with your business goals and your team structure.

Whichever path you choose, success depends on having senior engineers who are experts in these modern frameworks. That’s the problem we solve.