OneEntry and KMM: a unified platform for mobile development with Swift and Kotlin

Modern mobile development teams increasingly face the challenge of building reliable and scalable applications for both iOS and Android simultaneously. Developing separate native versions can lead to duplicated business logic, higher maintenance costs, and inconsistent behavior across platforms. In this context, solutions that allow teams to align their efforts and reduce repetitive work are particularly valuable.

The OneEntry platform, delivered as a PaaS solution, offers an architecture that integrates seamlessly with the Kotlin Multiplatform Mobile (KMM) approach. Together, they make it possible to extract business logic into a shared module and reuse it across both Kotlin and Swift-based projects.

The advantages of KMM for cross-platform business logic

Kotlin Multiplatform Mobile (KMM) enables teams to share business logic between Android and iOS while preserving the native user interface on each platform. This approach reduces code duplication, simplifies maintenance, and improves the consistency of application behavior.

For teams that include both Android and iOS developers, KMM creates the opportunity to collaborate within a unified codebase. Instead of implementing the same algorithms twice, developers can focus on architecture, security, and optimizing the shared logic layer.

Integration with OneEntry: SDK and unified data access

The OneEntry platform includes a ready-to-use SDK designed for use within a KMM architecture. The SDK provides type-safe and secure access to core system features such as user management, authentication, catalogs, and orders. It offers a unified interface for interacting with the API, significantly lowering the entry threshold and simplifying platform integration.

Developers can integrate the SDK into their Kotlin or Swift projects without the need to build their own server infrastructure. This is especially valuable for small and mid-sized teams that prioritize fast time-to-market and the ability to focus on client-side logic.

Application scaling scenarios with the OneEntry platform

As a mobile application grows, teams face the challenge of maintaining system stability while the number of users and overall load increases. This involves both technical risks-such as server overload, request processing delays, and performance degradation—and risks related to a declining user experience.

The OneEntry platform offers architectural solutions that enable both horizontal and vertical scaling, ensuring system resilience and predictable behavior even during peak traffic periods.

Load balancing

OneEntry implements automatic distribution of incoming requests across multiple servers. This prevents individual nodes from becoming overloaded and allows the application to handle traffic spikes, such as during seasonal sales or marketing campaigns, without disruptions. The load balancing mechanism is built into the platform, requires no manual configuration, and is optimized for multi-server environments.

Data and request caching

To improve performance, OneEntry uses a built-in caching mechanism. This enables repeated requests to be served without querying the database, reducing latency and easing the load on storage systems. Caching is especially effective for public or frequently accessed data, such as product cards, user profiles, or reference information. The cache is updated automatically when the source data changes, ensuring relevance without sacrificing speed.

Database optimization

OneEntry automatically optimizes SQL queries by using indexes and streamlined database interaction schemas. For large-scale systems, horizontal database scaling is supported—data is distributed across multiple storage nodes. This allows high volumes of parallel requests to be processed evenly, without performance degradation, and ensures the platform remains scalable as the user base grows.

Integrating KMM with a Swift Application Using SKIE

To integrate Kotlin Multiplatform Mobile (KMM) with an iOS application written in Swift using the Swift-Kotlin Interop Engine (SKIE), several steps are required.

Step 1: Creating a Kotlin/Native module

Create a new KMM project in Android Studio using the Kotlin Multiplatform App template. In the commonMain folder, define the shared modules and business logic that will be used in both the Android and iOS parts of the application.

To ensure proper operation of the OneEntry SDK, you need to add the following dependencies to the build.gradle.kts configuration file:

sourceSets {
    commonMain.dependencies {
        implementation("cloud.oneentry:sdk-catalog:1.2.6")
        implementation("cloud.oneentry:sdk-initialization:1.2.6")
    }
}

Step 2: Initializing the SDK in Kotlin (commonMain)

Initialize the OneEntry SDK in the shared layer of the application. Example code:

object MyApplication {
    fun initialize() {
        OneEntryCore.initialize(
            host = "sample.oneentry.cloud",
            token = "Paste your api token here"
        )
    }
}

Working with data: catalog usage example

class ProductsManager {
    @Throws(Throwable::class)
    suspend fun getProducts(): List<Product> {
        val result = CatalogService.all()

        // Your business logic here

        return result.items()
    }
}

Step 3: Using Kotlin code in Swift via SKIE

Import the Kotlin module into the Swift files of your project. Below is an example of calling business logic from Swift using SwiftUI:

import SwiftUI
import Shared

struct ContentView: View {
    @State var isLoading = false

    var body: some View {
        VStack {
            if !isLoading {
                Button("Click me!") {
                    isLoading = true

                    Task {
                        let manager = ProductsManager()
                        let products = try await manager.getProducts()

                        print("Products: \(products)")

                        isLoading = false
                    }
                }
            } else {
                ProgressView()
            }
        }
        .animation(.default, value: isLoading)
    }
}

#Preview {
    ContentView()
}

Technical aspects of integrating KMM and Swift

Integrating Kotlin Multiplatform Mobile (KMM) with iOS applications written in Swift is done through Objective-C interoperability and the SKIE extension (Swift-Kotlin Interoperability Enhancement). This approach allows shared code to be used across platforms and helps minimize duplication of business logic.

The setup requires:

• creating a Kotlin/Native module with a properly configured build.gradle.kts,
• connecting the shared module to the Xcode project,
• and using the generated bridges to access Kotlin functions from Swift code.

SKIE establishes a compatibility layer that ensures safe and predictable interaction between the two languages. It is important to maintain strict type compatibility and avoid complex nested structures that may be interpreted differently in Swift and Kotlin.

Recommendations for Kotlin developers

When implementing shared business logic, it is recommended to:

• use Kotlin Coroutines for asynchronous operations with APIs and data,
• apply Kotlin Serialization for safe and declarative JSON processing.

These tools improve code readability, support centralized error handling, and ensure strong compatibility with cross-platform architecture.

Security and data protection

The OneEntry platform implements a multi-layered security model that includes:

• authorization using access tokens,
• support for mTLS certificates for mutual authentication,
• API protection against unauthorized requests.

This architecture provides strong protection for user data and business logic, even under high load or in systems involving third-party integrations.

Common issues and how to avoid them

During KMM integration with a Swift application, developers often encounter challenges related to data type compatibility and asynchronous execution. The most frequent issues occur when passing complex structures between Kotlin and Swift, or when handling suspend functions and coroutines incorrectly.

To reduce these risks, it is recommended to:

• strictly follow consistent type definitions across both languages,
• use wrappers and adapters when working with shared structures,
• implement proper error handling mechanisms, including try/catch and safe callbacks on the Swift side.

The official documentation for Kotlin Multiplatform and Apple provides up-to-date guidance and practical examples that can help reduce debugging time and avoid architectural pitfalls.

The integration of OneEntry with Kotlin Multiplatform Mobile opens up new opportunities for mobile teams: rapid development, a unified architecture, and stable cross-platform business logic. Using OneEntry enables Swift and Kotlin developers to collaborate effectively, reduce maintenance costs, and improve product quality through centralized logic management and a secure API.
For teams focused on sustainable growth, scalability, and fast time-to-market, the combination of OneEntry + KMM provides a solid technological foundation for delivering complex mobile solutions with minimal overhead.