Kittysplit Blog

Llegan las cuentas: tus Kitties, seguros y sincronizados

Thu, 23 Apr 2026 00:00:00 +0000

Ya hay cuentas en Kittysplit. Inicia sesión (en la web, en iOS o en Android) y todos tus Kitties irán contigo. Es la novedad más grande que hemos lanzado en mucho tiempo, y es totalmente opcional.

¿Por qué cuentas?

Durante mucho tiempo, Kittysplit funcionó sin cuentas, y fue a propósito. Sin cuenta no hace falta registrarse, no hay contraseñas que recordar y no recogemos datos personales. Además, por aquel entonces no teníamos apps móviles, así que cambiar de dispositivo no era tanto problema.

Pero las cuentas fueron la petición número 1 en nuestra encuesta, y desde que lanzamos las apps móviles el año pasado nos las han pedido un montón de veces. ¡Así que por fin aquí están! Lanzar cuentas no es tan difícil. Lo complicado es que sigan siendo opcionales. Hizo falta planificarlo con mucho cuidado para que un Kitty funcione igual tanto si has iniciado sesión como si no.

Tus Kitties, en todos tus dispositivos

Inicia sesión en la web o en tu teléfono y encontrarás los mismos Kitties en todas partes. Se acabó rebuscar el enlace en chats antiguos. ¿Teléfono nuevo? ¿Has cambiado de navegador? Inicia sesión y sigue donde lo dejaste.


Iniciar sesión o registrarse	Tu perfil

Kitties más seguros

Si creas un Kitty con la sesión iniciada, es tuyo. Solo tú puedes editarlo o borrarlo, así que nada importante desaparece por accidente. Tus amigos pueden seguir añadiendo gastos y saldando cuentas como siempre. Para ellos no cambia nada.

Tus amigos no necesitan cuenta

Las cuentas son opcionales, y siempre lo serán. Invita a la gente como lo has hecho siempre: mándales el enlace y podrán empezar a repartir gastos al momento. Sin registros, sin complicaciones. Eso sigue siendo el corazón de Kittysplit.

Muy pronto: fotos de perfil

Lo siguiente son las fotos de perfil: sube una foto chula y en los Kitties de tus amigos serás algo más que un nombre. Y tenemos en camino unas cuantas ideas más solo para quien tenga cuenta.

¡Cuentas claras, amistades largas! 🐱✨

¿Tienes comentarios o ideas? Escríbenos en X, Bluesky, Instagram o mándanos un email a info[at]kittysplit.com

Archivos adjuntos: añade fotos a tus gastos

Thu, 12 Mar 2026 00:00:00 +0000

¡Ya puedes adjuntar archivos a los gastos en Kittysplit! A partir de ahora, cualquier gasto de tu Kitty puede llevar hasta 3 imágenes. Es una función de Super Kitty, así que tendrás que actualizar tu Kitty para usarla.

¿Qué hay de nuevo?

Ahora cada gasto puede llevar fotos. Haz una foto del recibo, de la cuenta del restaurante o de lo que toque repartir, y se queda ahí mismo, junto al gasto, para que todos la vean.

Puedes añadir hasta 3 imágenes por gasto, que debería bastar para casi todo. Piensa en recibos, facturas de hotel, entradas de conciertos o simplemente una foto de lo que has comprado, para que el grupo sepa a qué está poniendo dinero.

Se acabó bucear en la galería semanas después buscando aquel recibo. Lo adjuntas al añadir el gasto y listo.

Cómo funciona

Cuando añades o editas un gasto, verás una opción para adjuntar imágenes. Elige una de tu galería. Si más adelante quieres cambiarla, bórrala y añade otra.

Pruébalo

Actualiza a Super Kitty y adjunta fotos a tu próximo gasto. ¡Así de fácil!

¡Cuentas claras, amistades largas! 🐱✨

¿Tienes comentarios o ideas? Escríbenos en X, Bluesky, Instagram o mándanos un email a info[at]kittysplit.com

Presentamos las categorías de gastos: ve más claro en qué se va el dinero de tus Kitties

Wed, 11 Feb 2026 00:00:00 +0000

Tenemos una novedad que nos hace mucha ilusión: ¡categorías de gastos en Kittysplit! Desde hoy puedes ordenar cada gasto e ingreso de tus Kitties por categorías, y así ver mucho más claro en qué se va el dinero.


Añadir gasto	Filtrar por categoría

¿Qué hay de nuevo?

Cada gasto o ingreso que añadas a tu Kitty puede ir ahora en una de estas 12 categorías:

Vivienda - Alquiler, hipoteca, seguro del hogar y lo básico para la casa
Alojamiento - Hoteles, apartamentos vacacionales y estancias cortas
Comida y compras - La compra del súper y la comida para casa
Restaurantes y salidas - Restaurantes, bares, cafeterías y comida para llevar
Transporte - Gasolina, transporte público, viajes en coche compartido y coches de alquiler
Servicios y comunicaciones - Luz, agua, internet y teléfono
Salud - Gastos médicos, farmacia y seguro de salud
Ocio y actividades - Entretenimiento, actividades, conciertos y eventos
Compras y equipamiento - Ropa, electrónica y compras en general
Bienestar y cuidado personal - Gimnasio, spa, belleza y autocuidado
Finanzas y comisiones - Comisiones bancarias, cargos por servicio y otros gastos financieros
Varios - Todo lo que no encaja en ninguna otra

Cada categoría tiene su propio color, así que de un vistazo se ve enseguida por dónde va el dinero.

Filtra tus gastos

Lo primero que llega con las categorías es el filtro de gastos. Ahora puedes filtrar la lista de gastos por categoría y encontrar enseguida:

Todo lo gastado en restaurantes durante el viaje en grupo
Lo que se va en la compra en la casa compartida
Los gastos de transporte de la ruta en coche
Cualquier categoría que quieras revisar

Así es facilísimo responder a preguntas como “¿Cuánto nos hemos gastado en comida?” o “¿Cuánto nos costó el alojamiento en las vacaciones?”

¿Qué viene después?

Esto es solo el principio. Ya estamos trabajando en lo siguiente, para que le saques todavía más partido a tus gastos por categorías:

Comparación mes a mes

Mira cómo cambia el gasto de cada categoría con el tiempo. ¿La compra del súper sale cada vez más cara? ¿Este mes has salido a cenar menos que el anterior?

Tendencias

Descubre patrones y tendencias en tus gastos a lo largo de semanas, meses o incluso años. Ideal si compartes casa y quieres ajustar el presupuesto común.

Gráficos

Gráficos que muestran el reparto de tus gastos por categoría: de tarta para ver el total, de barras para comparar categorías y una línea de tiempo para ver cómo evoluciona el gasto.

¿Para qué sirven las categorías?

Tanto si compartes casa como si estás organizando unas vacaciones en grupo, las categorías te ayudan a:

Entender en qué se gasta - Mira a dónde va de verdad el dinero común
Planificar mejor - Usa lo que se gastó la última vez para calcular el presupuesto de la próxima
Tener las cosas claras - Todos en el grupo pueden ver el desglose por categorías

Empieza hoy mismo

Las categorías ya están disponibles en la última versión de Kittysplit. Añade o edita un gasto y verás la opción para asignarle una categoría. ¡Así de sencillo!

Como siempre, nos encantará saber qué te parece y qué te gustaría que mejoráramos.

¡Cuentas claras, amistades largas! 🐱✨

¿Se te ocurre cómo podrían funcionar mejor las categorías en tu caso? Escríbenos en X, Bluesky, Instagram o mándanos un email a info[at]kittysplit.com

Una vista general mejorada y avatares de gatos

Tue, 09 Dec 2025 00:00:00 +0000

Justo a tiempo para la Navidad de 2025, las apps de Kittysplit se actualizan (v1.3) con dos mejoras que teníamos ganas de hacer desde hace tiempo:

Una vista general rediseñada que te enseña lo importante sin ahogarte en números
Avatares de gatos para un aspecto más simpático y divertido

La vista general: antes y después

La vista general es lo primero que ves al abrir un Kitty. La hemos rehecho para que responda rápido a lo que más te interesa: ¿Cuánto ha costado el evento en total? ¿Quién le debe qué a quién? En general hemos intentado darle más estructura a todo con tarjetas de Material Design, y en algunas partes eso va más allá de la vista general.


Vista general del Kitty - antes	Vista general del Kitty - después


Vista general del Kitty - después (modo oscuro)	Gestionar participantes - después (modo oscuro)

Un avatar de gato para cada participante

Ahora, en cada Kitty, cada participante tiene su propio avatar de gato. Sí, le pega al nombre de Kittysplit, pero también hay motivos prácticos.

Los elementos visuales ayudan a encontrar la información más rápido que el texto solo. Con los gatos es más fácil:

Que la app parezca menos una hoja de cálculo
Reconocer a los participantes en grupos grandes
Ver quién pagó qué mientras repasas los gastos


Avatares de gatos (ejemplo)

Lo que no ha cambiado

No hace falta registrarse
Funciona en la web, en iOS y en Android
Cálculo inteligente de deudas
Gratis para la mayoría de funciones

Consigue la actualización

Si usas la app, te llegará la actualización a través del App Store o de Google Play.

Cuéntanos qué te parece en info[at]kittysplit.com o con el botón de comentarios.

Kittysplit's RevenueCat Shipaton 2025 Story

Tue, 30 Sep 2025 00:00:00 +0000

We’re excited to share our story for the RevenueCat Shipaton 2025! As part of this fun hackathon, we finally took the leap and shipped our long-awaited Android and iOS apps for Kittysplit. The Shipaton challenged us to not just build something new, but to actually ship it and that’s exactly what we needed to push our mobile apps from “someday” to “today.” Below is the story we submitted for the hackathon, chronicling our journey from a simple side project born during a ski trip to launching our mobile apps.

Kittysplit: Easy splitting of group expenses

Inspiration

Kittysplit started as a side project born from a real problem we faced during a ski trip with friends years ago. We were struggling to split our expenses fairly and efficiently. Excel felt clunky and overcomplicated for what should be a simple task. When we couldn’t find an existing tool that was truly easy to use, we decided to build our own.

What began as a web-only solution has grown organically over the years. We’ve continuously improved the platform based on constant feedback from our users, who have been incredibly helpful in shaping what Kittysplit has become today. As our user base grew, one request kept coming up:

“When will you have mobile apps?”

We started working on the apps when we had time, but participating in this hackathon gave us the final push to finish and ship them to the app stores.

What it does

Kittysplit solves one problem really well: making group expense splitting effortless. Whether you’re on vacation with friends, sharing household costs with roommates, or organizing a group dinner, our app provides the simplest way to calculate who owes what to whom. No overcomplicated features, no confusing interfaces: just straightforward expense splitting that anyone can understand.

How we built it

The journey to mobile started with building an API to integrate with our existing web application. Our initial plan was ambitious: use Kotlin Multiplatform for shared business logic, networking, local storage, and calculations, and build two separate user interfaces: a Jetpack Compose UI for Android, and a native SwiftUI frontend for iOS.

Since we already had Android development experience, we began with the Android app and built the multiplatform part and the Compose UI for Android. We took great care to keep our client side business logic fully separate from the UI implementation by using ViewModels with StateFlow in Kotlin multiplatform. This allowed us to reuse all business logic for our iOS app. For the multiplatform payment system integration, we used RevenueCat - it turns out that Kittysplit and RevenueCat are a purrr-fect combination!

Then we started working on the SwiftUI client. Initially, it seemed quite straightforward and using our KMP ViewModels from SwiftUI code worked really well. However during the process, it turned out to be a lot more work than expected. We also realized that building our UI in Compose was much easier than in SwiftUI, and that Compose Multiplatform would save us significant development time and effort. This pivot allowed us to share not just the business logic, but also most of the UI code between platforms.

Challenges we ran into

Most of our challenges were product-focused rather than technical. The biggest question was how to translate the simple, intuitive flows that work well on the web into mobile app experiences. We spent considerable time ensuring that the mobile version maintained the same simplicity that makes our web app successful. Keeping the product simple sounds easy, but the big challenge is hiding the technical and mathematical complexity from the user and make it all work intuitively.

On the technical side, we took great care to keep our client side business logic separate from the UI implementation by using ViewModels in Kotlin multiplatform. The main challenge was realizing that building and maintaining a separate iOS frontend in SwiftUI besides our existing backend, web UI and the Android Compose app was too much work for us, as a small team of 3 people working part-time on this project. So we ditched our half finished SwiftUI app even though we already spent a lot of time on it. The switch to Compose Multiplatform was easier than expected and crucial to get the iOS app released soon after Android.

Accomplishments that we’re proud of

The user response has been incredibly encouraging. Already during the beta phase, we received a lot of positive feedback from users. Many of our existing web users are actively switching to the mobile apps, which validates that our concept translates well to mobile. And new users already say that after trying several established competitor’s apps, they are happy to have found the Kittysplit app.

What makes us most proud is that users immediately understand how to use the app. The simplicity and intuitive design we worked so hard to achieve on the web has successfully carried over to mobile. Users can start splitting expenses within seconds of opening the app.

What we learned

The technical transition from Android Compose to Compose Multiplatform turned out to be surprisingly smooth. We learned a lot about both technologies throughout the process.

Perhaps the most interesting learning curve was diving into the iOS ecosystem for the first time. We spent considerable time learning Swift and SwiftUI, only to eventually abandon that code when we switched to Compose Multiplatform. While it felt like wasted effort initially, understanding iOS development principles helped us make better decisions for the multiplatform approach.

We also learned the intricacies of iOS app publishing which was a completely new world for us as primarily Android developers.

What’s next for Kittysplit

Our immediate focus is on App Store Optimization to grow our mobile user base.

We’re committed to continuing our user feedback driven development approach. Our feature roadmap includes several highly requested additions:

Expense attachments (receipts, photos)
Expense categories for better organization
Push notifications to keep everyone updated
And much more!

The goal remains the same: keep Kittysplit the easiest way to split group expenses, whether you’re using our web app or mobile apps.

Collecting Reviews in a Compose Multiplatform App

Fri, 26 Sep 2025 00:00:00 +0000

Shipping a great app is only half the battle, earning high quality reviews is just as crucial for App Store Optimization (ASO). Ratings and reviews shape first impressions, drive conversion, and influence store ranking. For a product like Kittysplit, where trust and simplicity are everything, timely and authentic user feedback helps future users decide to install, and helps us steer the roadmap.

But asking for reviews is a delicate craft. Prompt too early and you interrupt the flow, prompt too often and you annoy users, prompt at the wrong moment and you get low‑quality or frustrated feedback. In this post, we’ll share how we integrated Google Play’s ReviewManager and Apple’s SKStoreReviewController into our Compose Multiplatform app, and how we built a cross‑platform strategy to decide when to ask. We’ll cover the technical glue, the platform nuances, and the heuristics we use to surface the prompt at moments when users are most likely to feel satisfied, not interrupted.

Implementation

We’ll start with the implementation. We define a shared ReviewService API in common code and provide platform-specific implementations that wrap Android’s ReviewManager and iOS’s SKStoreReviewController. Using Kotlin Mutliplatform’s expect/actual mechanism in combination with Koin, we’re providing the correct implementation for each platform. This keeps the call site in our Compose Multiplatform UI identical across platforms, while letting each target handle its own prompt presentation in a native, compliant way.

We’re using a freshly created Compose Multiplatform project as the base for this post. You can find a little more detailed description of how to create a new CMP project in our previous blog post here. You can find all the code on GitHub.

At first, we need to add a few dependencies to our libs.versions.toml. If you don’t know what that is, you can read up on it here. It’s a relatively new way of managing dependencies in gradle.

[versions]
# ... other verions

android-play-review = "2.0.2"
koin = "4.1.1"
kotlinx-coroutines = "1.10.2"

[libraries]
# ... other libraries

android-play-review = { module = "com.google.android.play:review", version.ref = "android-play-review" }
android-play-review-ktx = { module = "com.google.android.play:review-ktx", version.ref = "android-play-review" }
koin-compose = { module = "io.insert-koin:koin-compose", version.ref = "koin" }
koin-core = { module = "io.insert-koin:koin-core", version.ref = "koin" }
kotlinx-coroutines-core = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-core", version.ref = "kotlinx-coroutines" }
kotlinx-coroutines-play-services = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-play-services", version.ref = "kotlinx-coroutines" }

./gradle/libs.versions.toml

Next, we’re going to declare these dependencies in our compose app’s build.gradle.kts:

kotlin {
    // ... other settings

    sourceSets {
        androidMain.dependencies {
            // ... other android dependencies

            implementation(libs.android.play.review)
            implementation(libs.android.play.review.ktx)
            implementation(libs.kotlinx.coroutines.play.services)
        }
        commonMain.dependencies {
            // ... other common dependencies

            implementation(libs.koin.core)
            implementation(libs.koin.compose)
            implementation(libs.kotlinx.coroutines.core)
        }
    }
}

./composeApp/build.gradle.kts

Now we need to define an interface in commonMain that we’ll implement later in androidMain and iosMain respectively:

interface ActivityContainer

data object EmptyActivityContainer : ActivityContainer

sealed class ReviewResult() {
    data object Requested : ReviewResult()
    data object Failed : ReviewResult()
    data class RequestError(val code: Int) : ReviewResult()
}

interface ReviewService {
    suspend fun requestInAppReview(
        activityContainer: ActivityContainer = EmptyActivityContainer
    ): ReviewResult
}

./composeApp/src/commonMain/kotlin/com/kittysplit/reviewservicecmp/ReviewService.kt

Because Apple’s SKStoreReviewController and Google Play’s ReviewManager don’t expose whether a dialog was actually shown or acted upon, our API only reports Requested or an error. This keeps our contract honest and portable across both stores’ opaque review flows. Don’t mind the ActivityContainer interface and EmptyActivityContainer object, we’re going to explain that soon.

Android

Let’s look at the implementation for Android:

import android.app.Activity
import android.content.Context
import com.google.android.play.core.review.ReviewException
import com.google.android.play.core.review.ReviewManagerFactory
import kotlinx.coroutines.tasks.await

data class AndroidContextHolder(val activity: Activity) : ActivityContainer

fun ActivityContainer.activity(): Activity? = (this as? AndroidContextHolder)?.activity

class AndroidReviewService(val context: Context) : ReviewService {
    private val reviewManager = ReviewManagerFactory.create(context)

    override suspend fun requestInAppReview(activityContainer: ActivityContainer): ReviewResult = try {
        val activity = activityContainer.activity()
        if (activity != null) {
            val reviewInfo = reviewManager.requestReviewFlow().await()
            reviewManager.launchReviewFlow(activity, reviewInfo).await()
            ReviewResult.Requested
        } else {
            ReviewResult.Failed
        }
    } catch (error: Exception) {
        if (error is ReviewException) {
            ReviewResult.RequestError(error.errorCode)
        } else {
            ReviewResult.Failed
        }
    }
}

./composeApp/src/androidMain/kotlin/com/kittysplit/reviewservicecmp/AndroidReviewService.kt

We implemented the Android side of ReviewService using Play Core’s in‑app review flow. AndroidReviewService creates a ReviewManager, requests a ReviewInfo using requestReviewFlow().await(), and then launches the prompt with reviewManager.launchReviewFlow(...).await(). Because launchReviewFlow requires an Activity, not a generic Context, we created a small container object to be able to hand over the Activity in the Android implementation. For iOS, we’re going to use the EmptyActivityContainer, since we don’t need to pass anything there.

If something goes wrong on Android, the ReviewManager might throw a ReviewException. In case we encounter it, we’re extracting the errorCode and return it as ReviewResult.RequestError. This allows you to handle these errors separately from the generic ReviewResult.Failed. For possible values of the errorCode see the documentation here.

iOS

Next, we’re going to implement the AppleReviewService in iosMain:

import platform.StoreKit.SKStoreReviewController
import platform.UIKit.UIApplication
import platform.UIKit.UISceneActivationStateForegroundActive
import platform.UIKit.UIWindowScene

class AppleReviewService : ReviewService {
    override suspend fun requestInAppReview(activityContainer: ActivityContainer): ReviewResult = try {
        val scene = UIApplication.sharedApplication.connectedScenes
            .filterIsInstance<UIWindowScene>()
            .firstOrNull { it.activationState == UISceneActivationStateForegroundActive }

        if (scene != null) {
            SKStoreReviewController.requestReviewInScene(scene)
        } else {
            SKStoreReviewController.requestReview()
        }
        ReviewResult.Requested
    } catch (_: Exception) {
        ReviewResult.Failed
    }
}

./composeApp/src/iosMain/kotlin/com/kittysplit/reviewservicecmp/AppleReviewService.kt

We implemented the iOS side with StoreKit’s in‑app review API. AppleReviewService looks up the currently active UIWindowScene by scanning UIApplication.sharedApplication.connectedScenes and picking the one in UISceneActivationStateForegroundActive state. If an active scene exists, we call SKStoreReviewController.requestReviewInScene(scene). Otherwise we fall back to SKStoreReviewController.requestReview(). Both calls are “fire‑and‑forget” (no success callback), so we return ReviewResult.Requested after invoking them. Any exception during lookup or invocation maps to ReviewResult.Failed. This approach ensures the prompt is tied to the foreground scene in multi‑window setups while remaining compatible with older, scene‑agnostic code paths.

Koin

That’s it. All we need to do now is wire it all together to be able to use it in our common app code. We’re going to use Koin for that, but you can go with any other DI framework.

import org.koin.core.module.Module

expect fun reviewModule(): Module

./composeApp/src/commonMain/kotlin/com/kittysplit/reviewservicecmp/ReviewModule.kt

import org.koin.core.module.Module
import org.koin.core.module.dsl.singleOf
import org.koin.dsl.module

actual fun reviewModule(): Module = module {
    singleOf(::AndroidReviewService)
}

./composeApp/src/androidMain/kotlin/com/kittysplit/reviewservicecmp/ReviewModule.android.kt

import org.koin.core.module.Module
import org.koin.core.module.dsl.singleOf
import org.koin.dsl.module

actual fun reviewModule(): Module = module {
    singleOf(::AppleReviewService)
}

./composeApp/src/iosMain/kotlin/com/kittysplit/reviewservicecmp/ReviewModule.ios.kt

We’re not going in detail here, but it should be straight forward. We’re defining a reviewModule() as an expect function and provide the platform-specific implementations in the actual counterparts.

With both implementations in place, you can inject ReviewService into any ViewModel and trigger review requests at the right moments in your user flows. Pick thoughtful triggers, wire them to requestInAppReview, and you’re ready to ask for reviews without disrupting your users.

Review triggers

We gate review prompts behind lightweight heuristics so they appear at moments of success, not interruption. We track when the app was first opened, total opens, when we last requested a review, and how many expenses a user has added. We use two trigger events: when a user adds an expense and when they settle up. We prioritized the settle-up event because it aligns with a clear success moment. Our heuristics are:

Last review request ≥ x days ago
First app open ≥ x days ago
App opened ≥ x times
Current Kitty has ≥ x expenses

We apply these on both platforms, but we’re more conservative on iOS, prompting less frequently and only after stronger engagement because the app is only three weeks old, and because Apple only displays the review prompt maximum 3 times a year.

Collecting reviews is both a technical integration and a product judgment call. With a shared ReviewService and platform-native implementations for Android’s ReviewManager and iOS’s SKStoreReviewController, you now have a clean way to prompt your users for reviews from your common code. Pair that with thoughtful heuristics that favor genuine success moments, and you’ll nudge happy users to share feedback without breaking their flow, ultimately improving ASO, conversion, and the product itself.

If you try this approach in your own Compose Multiplatform app, we’d love to hear what heuristics work best for you. Feels free to contact us on social networks (X, Bluesky, Instagram) or write an email.

Firebase Analytics in Compose Multiplatform without Cocoapods

Tue, 23 Sep 2025 00:00:00 +0000

At Kittysplit, we’ve always aimed to make splitting group expenses as effortless as possible. For years, Kittysplit was a web first product. As our users took Kittysplit on trips, into shared apartments, and to events, it became clear that we needed mobile apps on both Android and iOS.

In this post, we’ll provide a hands-on guide how we wired Firebase Analytics into our Compose Multiplatform app on both Android and iOS without using Cocoapods (which is going to retire soon).

From SwiftUI to Compose Multiplatform

We embraced Kotlin Multiplatform to share business logic across platforms, initially pairing it with a native Android app and a SwiftUI app for iOS, each with its own Firebase Analytics integration.

But when we decided to fully commit to Compose Multiplatform and retire our SwiftUI app, we hit a wall: there’s no out of the box way to use Firebase Analytics in a Compose Multiplatform project. Also, Cocoapods is going to retire soon. Instead, we’ll use the Swift Package Manager dependencies directly with the wonderful spm4Kmp plugin made by François. We’re also going to use Koin to wire it all together.

Project setup

We’re going to add Firebase Analytics to a newly created Compose Multiplatform project, which we’re creating using the new project wizard in Android Studio. If you want to follow along, you can either check out the project code from GitHub or create a new project yourself.

To create a new CMP project in Android Studio, make sure you have the Kotlin Multiplatform plugin installed. You can then click File -> New -> New Project.... Under “Phone and Tablet” select “Kotlin Multiplatform”, enter a name and package for your app and click “Next”. On the next screen, make sure you have the Android and iOS boxes ticked and select “Share UI” as UI implementation. Click “Finish” to create the new project.

Dependencies

Our first step is to add the needed dependencies. To do this, we’re going to use the gradle version catalog. Locate the libs.versions.toml file and add the following lines:

[versions]
# ... other dependencies

koin = "4.1.1"
spm4kmp = "1.0.0-Beta04"
firebase-analytics = "22.5.0"
google-services = "4.4.3"

# spm
spm-firebase = "12.0.0"

[libraries]
# ... other libraries

koin-compose = { module = "io.insert-koin:koin-compose", version.ref = "koin" }
koin-core = { module = "io.insert-koin:koin-core", version.ref = "koin" }
firebase-analytics-ktx = { module = "com.google.firebase:firebase-analytics-ktx", version.ref = "firebase-analytics" }

[plugins]
# ... other plugins

spm4kmp = { id = "io.github.frankois944.spmForKmp", version.ref = "spm4kmp"}
google-services = { id = "com.google.gms.google-services", version.ref = "google-services" }

./gradle/libs.versions.toml

You can now sync your project with the gradle files to pull in the dependencies. With this out of the way, we’re going to declare the dependencies in our build.gradle.kts files. We’ll start with the root build.gradle.kts file. Add this line:

plugins {
    // other plugins

    alias(libs.plugins.spm4kmp) apply false
    alias(libs.plugins.google.services) apply false
}

./build.gradle.kts

This just tells gradle to resolve the plugin, but not apply it. This is useful if you have a multi-module gradle project and only want to apply the plugin in a single submodule.

Now we’re going to set up the gradle.build.kts of our composeApp:

plugins {
    // other plugins

    alias(libs.plugins.spm4kmp)
    alias(libs.plugins.google.services)
}


kotlin {
    // ...

    listOf(
        iosArm64(),
        iosSimulatorArm64()
    ).forEach { iosTarget ->
        iosTarget.binaries.framework {
            baseName = "ComposeApp"
            binaryOption("bundleId", "com.kittysplit.firebase_analytics_cmp")
            isStatic = true
        }
        // This is the important part:
        iosTarget.compilations {
            val main by getting {
                cinterops.create("nativeIosShared")
            }
        }
    }

    sourceSets {
        named { it.lowercase().startsWith("ios") }.configureEach {
            languageSettings {
                optIn("kotlinx.cinterop.ExperimentalForeignApi")
            }
        }

        androidMain.dependencies {
            // ...
            implementation(libs.firebase.analytics.ktx)
        }

        commonMain.dependencies {
            // ...

            api(libs.koin.compose)
            api(libs.koin.core)
        }
    }

    swiftPackageConfig {
        create("nativeIosShared") {
            minIos = "16.0"
            dependency {
                remotePackageVersion(
                    url = uri("https://github.com/firebase/firebase-ios-sdk.git"),
                    products = {
                        add("FirebaseAnalytics", exportToKotlin = true)
                        add("FirebaseCore", exportToKotlin = true)
                    },
                    packageName = "firebase-ios-sdk",
                    version = libs.versions.spm.firebase.get(),
                )
            }
        }
    }
}

./composeApp/build.gradle.kts

That’s all dependency juggling. We added koin as “regular” multiplatform dependency of commonMain. For the Android implementation of Firebase Analytics, we added the Android library to androidMain. To be able to use the iOS Firebase Analytics in our iosMain implementation, we used spm4Kmp to declare the dependency. Notice the exportToKotlin = true, this tells spm4Kmp to export the dependency to kotlin, which means we can use it directly in iosMain code.

When you sync the project again, you’ll notice a new folder: ./composeApp/exportedNativeIosShared. This is the generated swift package which we’re going to add as a dependency to the iOS app next. Open XCode and navigate to the project dependencies:

XCode: iosApp -> PROJECT (iosApp) -> Package Dependencies

Click on the little “+” sign and then on “Add Local…”. Now select the aforementioned folder and click “Add package”. Once done, you’ll see all dependencies of Firebase Analytics and Firebase itself in your package dependencies on the lower left of your XCode window.

Firebase setup

To function properly, you need to register your Android and iOS Apps with Firebase. We’re not going to explain this in detail in this blogpost. Essentially, you need to provide a GoogleService-Info.plist file on iOS and a google-services.json file on Android. You can find an in depth guide for Android here. The guide for iOS is located here. Please note that you only need to follow the steps to obtain the aforementioned files, all other parts are covered in this blog post.

Implementation

This completes the boring part. We’re going to look at the implementation next. Our goal is to create a simple interface that allows us to track events to Firebase Analytics from view models, but also from Composables.

We’re starting by creating a simple interface inside commonMain, which we’re going to implement in androidMain and iosMain:

package com.kittysplit.firebase_analytics_cmp.analytics

interface Analytics {
    fun init()
    fun logEvent(name: String, params: Map<String, Any>?)
}

./composeApp/src/commonMain/kotlin/com/kittysplit/firebase_analytics_cmp/analytics/Analytics.kt

For the Android implementation, we’re going to use the kotlin Firebase SDK in androidMain:

package com.kittysplit.firebase_analytics_cmp.analytics

import androidx.core.os.bundleOf
import com.google.firebase.analytics.FirebaseAnalytics
import com.google.firebase.analytics.ktx.analytics
import com.google.firebase.ktx.Firebase

class AndroidAnalytics : Analytics {
    private lateinit var firebaseAnalytics: FirebaseAnalytics

    override fun init() {
        firebaseAnalytics = Firebase.analytics
    }

    override fun logEvent(
        name: String,
        params: Map<String, Any>?
    ) {
        val args = params
            ?.map { it.key to it.value }
            ?.toTypedArray()
            ?.let { bundleOf(*it) }

        firebaseAnalytics.logEvent(name, args)
    }
}

./composeApp/src/androidMain/kotlin/com/kittysplit/firebase_analytics_cmp/analytics/AndroidAnalytics.kt

As you can see, the implementation is straight forward. All we have to do is to convert our parameter map to a Bundle, which is often used in Android to pass data around.

On to the iOS implementation. We’re going to use the native iOS Firebase Analytics SDK in iosMain:

package com.kittysplit.firebase_analytics_cmp.analytics

import FirebaseAnalytics.FIRAnalytics
import FirebaseCore.FIRApp

class AppleAnalytics : Analytics {

    private val firAnalytics: FIRAnalytics.Companion = FIRAnalytics

    override fun init() {
        FIRApp.configure()
    }

    override fun logEvent(
        name: String,
        params: Map<String, String>?
    ) {
        firAnalytics.logEventWithName(name, params as Map<Any?, *>?)
    }
}

./composeApp/src/iosMain/kotlin/com/kittysplit/firebase_analytics_cmp/analytics/AppleAnalytics.kt

Dependency injection

All that is left to do now is to wire it all up using koin. We’ll have to create a module that provides our AppleAnalytics if we’re running on iOS and the AndroidAnalytics implementation if we’re running on Android. That’s where kotlin’s easy to use [expect/actual declarations] https://www.jetbrains.com/help/kotlin-multiplatform-dev/multiplatform-expect-actual.html come in.

In commonMain, we’re only declaring our module as an expect function, which is comparable to an interface where the implementation are provided per platform:

package com.kittysplit.firebase_analytics_cmp.analytics

import org.koin.core.module.Module

expect fun analyticsModule(): Module

./composeApp/src/commonMain/kotlin/com/kittysplit/firebase_analytics_cmp/analytics/AnalyticsModule.kt

Next, we’re providing the implementations for Android:

package com.kittysplit.firebase_analytics_cmp.analytics

import org.koin.core.module.Module
import org.koin.dsl.module

actual fun analyticsModule(): Module = module {
    single<Analytics> {
        val analytics = AndroidAnalytics()
        analytics.init()
        analytics
    }
}

./composeApp/src/androidMain/kotlin/com/kittysplit/firebase_analytics_cmp/analytics/AnalyticsModule.android.kt

And iOS:

package com.kittysplit.firebase_analytics_cmp.analytics

import org.koin.core.module.Module
import org.koin.dsl.module


actual fun analyticsModule(): Module = module {
    single<Analytics> {
        val analytics = AppleAnalytics()
        analytics.init()
        analytics
    }
}

./composeApp/src/iosMain/kotlin/com/kittysplit/firebase_analytics_cmp/analytics/AnalyticsModule.ios.kt

It’s important to call init on our implementations, to make sure they’re ready to go when they’re injected. Now we have to make sure that koin knows about the module we’ve just created. We’re going to do that by starting koin when our application starts. On Android, we can easily do that in the MainActivity:

package com.kittysplit.firebase_analytics_cmp

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.activity.enableEdgeToEdge
import androidx.compose.runtime.Composable
import androidx.compose.ui.tooling.preview.Preview
import com.kittysplit.firebase_analytics_cmp.analytics.analyticsModule
import org.koin.compose.KoinApplication

class MainActivity : ComponentActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        enableEdgeToEdge()
        super.onCreate(savedInstanceState)

        setContent {
            KoinApplication(application = {
                modules(analyticsModule())
            }) {
                App()
            }
        }
    }
}

./composeApp/src/androidMain/kotlin/com/kittysplit/firebase_analytics_cmp/MainActivity.kt

To make it work on iOS, we need to start the koin application in the MainViewController:

package com.kittysplit.firebase_analytics_cmp

import androidx.compose.ui.window.ComposeUIViewController
import com.kittysplit.firebase_analytics_cmp.analytics.analyticsModule
import org.koin.compose.KoinApplication

fun MainViewController() = ComposeUIViewController {
    KoinApplication(application = {
        modules(analyticsModule())
    }) { App() }
}

./composeApp/src/iosMain/kotlin/com/kittysplit/firebase_analytics_cmp/MainViewController.kt

Now we’re ready to inject our analytics implementation anywhere we need it. To test it, we’re going to use it to track the tap on the “Click me!” button from the example:

package com.kittysplit.firebase_analytics_cmp

// ... imports
import com.kittysplit.firebase_analytics_cmp.analytics.Analytics
import org.koin.compose.koinInject

@Composable
fun App(analytics: Analytics = koinInject()) {
    MaterialTheme {
        var showContent by remember { mutableStateOf(false) }
        Column(
            modifier = Modifier
                .background(MaterialTheme.colorScheme.primaryContainer)
                .safeContentPadding()
                .fillMaxSize(),
            horizontalAlignment = Alignment.CenterHorizontally,
        ) {
            Button(onClick = {
                analytics.logEvent("button_clicked", null)
                showContent = !showContent
            }) {
                Text("Click me!")
            }
            AnimatedVisibility(showContent) {
                val greeting = remember { Greeting().greet() }
                Column(
                    modifier = Modifier.fillMaxWidth(),
                    horizontalAlignment = Alignment.CenterHorizontally,
                ) {
                    Image(painterResource(Res.drawable.compose_multiplatform), null)
                    Text("Compose: $greeting")
                }
            }
        }
    }
}

./composeApp/src/commonMain/kotlin/com/kittysplit/firebase_analytics_cmp/App.kt

That’s it! You’re now ready to track events from anywhere in your Android Compose app. There’s one little thing we need to fix. You might have noticed that your preview is not showing any longer. That’s because koin is not initialized. Luckily, there’s a fix for that: we’re going to provide a fake instance of our Analytics for previews:

package com.kittysplit.firebase_analytics_cmp.analytics

import org.koin.dsl.module

fun noopAnalyticsModule() = module {
    single<Analytics> {
        object : Analytics {
            override fun init() {}

            override fun logEvent(name: String, params: Map<String, String>?) {}
        }
    }
}

./composeApp/src/commonMain/kotlin/com/kittysplit/firebase_analytics_cmp/analytics/NoopAnalyticsModule.kt

Now all we have to do is wrap our previews with a little helper:

@Preview
@Composable
fun AppPreview() {
    KoinApplicationPreview(application = { modules(noopAnalyticsModule()) }) {
        App()
    }
}

Now you should see the preview again.

We hope this little guide helps you in your multiplatform endeavours. We had a lot of fun implementing the Kittysplit apps in Compose Multiplatform.

Building Kittysplit's Mobile Apps in Compose Multiplatform

Thu, 18 Sep 2025 00:00:00 +0000

After 13 years as a web only application, Kittysplit has finally made the leap to mobile. We initially planned to build separate Android and iOS apps using Kotlin Multiplatform for shared business logic, but Compose Multiplatform’s recent stability changed everything. Here’s how we went from web only to native mobile apps.

From Web only to Mobile: A 13 Year Journey

Kittysplit started as a web application back in 2012. For over a decade, we maintained it exclusively as a webapp. The web platform allowed us to provide universal accessibility. Anyone could create or join a Kitty simply by opening a link in their browser, regardless of their device type. This cross platform compatibility is crucial for group expense sharing, where participants often use different devices and operating systems.

Growing Demand for Native Apps

However, user requests for dedicated mobile apps grew year after year. We felt that we needed to address this demand, so we looked at the available options for the implementation. We evaluated React Native, Flutter, Kotlin Multiplatform, and Compose Multiplatform to determine the best approach for our small development team.

Because we already had experience with Android development, we chose Kotlin Multiplatform as our foundation. Our initial plan was straightforward: develop the Android app first using Android Compose, while implementing all business logic in a shared module in Kotlin Multiplatform. This would allow us to share the core functionality across platforms: networking, business logic, calculations and local storage. We planned to build the iOS app using SwiftUI after completing the Android app, leveraging the already written shared business logic.

The Power of Kotlin Multiplatform

Kotlin Multiplatform proved to be an excellent choice for our architecture. We implemented all networking, local storage, and client-side calculations in the shared multiplatform code. Additionally, we moved all our ViewModels into the shared codebase, ensuring consistent business logic and state management across both platforms.

The implementation was straightforward: Kotlin provided almost everything we needed out of the box. For local data storage, we used SQLDelight, which allowed us to write type-safe SQL queries. We integrated the RevenueCat Purchases multiplatform SDK for handling Super Kitty upgrades. To enhance the Swift interoperability for our planned iOS development, we used SKIE from TouchLab. For dependency injection, we chose Koin, which worked seamlessly across our multiplatform setup. This foundation gave us confidence that we could maintain a single source of truth for our core functionality while building native experiences on each platform.

Compose Multiplatform Goes Stable

As it’s often the case in software development, the SwiftUI frontend turned out to be more work than we initially anticipated 🙈. We had been following Compose Multiplatform’s development for some time. Given the challenges we were facing with SwiftUI, we decided to experiment with it for a few days. Compose Multiplatform for iOS had recently reached stable status in May 2025.

We managed to migrate our app to Compose Multiplatform within just a few days, which was much faster than we expected. The resulting app ran smoothly on our iOS devices and felt really well.

This led us to ditch the native SwiftUI frontend entirely and go with Compose Multiplatform instead. It would save us months of work, both now and in the future. With only one codebase to maintain, we can spend our time improving the app and adding new features rather than implementing everything twice.

Kittysplit on iOS

The Migration Process: From Android Compose to Compose Multiplatform

The actual migration process was surprisingly straightforward. We started by importing the new Compose Multiplatform dependencies and migrating to multiplatform resources, which was mostly just copying a few files to the new structure. The main code changes involved removing usages of the Android Context throughout our codebase.

Fortunately, we had already been using multiplatform libraries from Sentry and RevenueCat, so those integrations continued to work without any changes. For Firebase Analytics, we used the expect/actual mechanism to provide platform-specific implementations. We also needed to make our deep links work on both platforms, but the patterns were similar enough that it didn’t require major restructuring.

Most of our existing Compose UI code worked with minimal adjustments, and the shared ViewModels we had already implemented in Kotlin Multiplatform integrated seamlessly. Within just a few days, we had a fully functional iOS app that felt genuinely good.

Looking Forward

We’re excited about the future of Kittysplit’s mobile apps with this technology stack. Kotlin Multiplatform and Compose Multiplatform have given us the perfect balance of development efficiency and native performance. With a single codebase to maintain, we can focus on what matters most: building features that make splitting expenses even easier for our users. We’re already working on several improvements and new features that would have taken us much longer to implement across separate platforms. The mobile app journey has finally found its ideal technical foundation, and we couldn’t be more excited about where it’s headed.

Kittysplit se hace móvil: ya tenemos apps para Android e iOS

Wed, 10 Sep 2025 00:00:00 +0000

Después de más de diez años siendo solo una web, ¡Kittysplit por fin tiene apps nativas para Android e iOS! Desde que empezamos en 2012, hemos ayudado a grupos de amigos, compañeros de casa y gente de viaje a repartir gastos de forma justa y sin líos, todo a través de nuestra web.

¿Por qué apps? ¿Y por qué ahora?

Siempre hemos querido que repartir gastos fuera lo más accesible posible. Durante años, nuestra web ha funcionado muy bien: cualquiera con un navegador podía llevar los gastos de su grupo sin complicaciones. Pero hemos escuchado lo que nos pide la gente, y muchos prefieren la comodidad de una app de verdad en el teléfono:

Acceso inmediato: a los gastos de tu grupo sin abrir el navegador
Una experiencia más fluida: pensada especialmente para el teléfono

El Kittysplit de siempre

Estamos muy contentos de tener por fin apps, pero tranquilidad: Kittysplit sigue funcionando igual. Seguimos apostando por lo mismo:

Sencillez: Nada de funciones complicadas que no necesitas.
Sin registro: Crea Kitties sin crear una cuenta.
Repartos justos: Varias formas de dividir los gastos para que a nadie le toque de más.
Lo básico, gratis: Las funciones principales siguen siendo gratuitas.
La app no es obligatoria: Las apps son nuestra forma de ofrecer una experiencia más cómoda en el teléfono, pero Kittysplit en la web sigue y seguirá.

Seguimos apostando por la web

Nos gusta que puedas elegir. Por mucho que nos alegre tener por fin apps, queremos dejar algo claro: la web sigue siendo igual de importante para nosotros. Sabemos que no todo el mundo quiere descargarse otra app más, y para mucha gente la flexibilidad de la web vale oro.

La versión web de Kittysplit va a seguir recibiendo el mismo cariño, las mismas actualizaciones y las mismas funciones nuevas que las apps.

¡Descárgala hoy!

Las nuevas apps ya están disponibles en el App Store de Apple y en Google Play. Tanto si llevas años usando Kittysplit como si nos acabas de descubrir, te invitamos a probar la app, y la web sigue ahí siempre que la necesites.

O sigue usando nuestra web en kittysplit.com

¿Y ahora qué?

Esto es solo el principio. Ya estamos trabajando en mejoras y nuevas funciones a partir de todos los comentarios que nos llegan.

¡Nos encantará saber qué te parecen las nuevas apps y qué te gustaría que mejoráramos! Como siempre, queremos que repartir gastos sea lo más fácil y tranquilo posible, ahora también en más plataformas.

Adsense está roto

Thu, 28 Mar 2024 00:00:00 +0000

Ya tuvimos problemas con anuncios fraudulentos en Adsense hace unos años. Aunque las estafas tan descaradas como el falso aviso de virus de 2018 parecen haber desaparecido, han aparecido otros anuncios fraudulentos.

El año pasado, una persona nos escribió para pedirnos que canceláramos su suscripción, pero Kittysplit no tiene suscripciones. Enseguida nos dimos cuenta de que la habían estafado con un anuncio fraudulento que le salió mientras usaba Kittysplit en el teléfono.

Cómo la engañaron

La estafa es sencilla: el anuncio muestra un enorme botón verde de START que se hace pasar por parte de Kittysplit. Pero el botón lleva a una web de terceros que pide los datos de la tarjeta de crédito. La web hace creer que el pago es por un servicio de Kittysplit (por ejemplo, saldar cuentas con tus amigos o el uso de la web). Al principio es gratis o casi gratis, pero luego empieza a cobrar una suscripción mensual de entre 20 y 60 €/$/£ por un servicio que la persona nunca quiso.

Aquí tienes una captura de pantalla de uno de estos anuncios engañosos:

En cuanto nos enteramos del problema, actuamos rápido y empezamos a bloquear esos anuncios en el centro de revisión de anuncios de Adsense. Durante un tiempo pareció que se había solucionado, pero los anuncios volvían una y otra vez en distintas variantes: siempre un botón grande y llamativo que decía START, CONTINUE, NEXT, DOWNLOAD o algo parecido.

Hace unos meses nos escribió otra persona a la que también habían estafado con estos anuncios. Así que bloqueamos los anuncios engañosos una y otra vez: pasamos muchísimas horas bloqueando miles de anuncios y cientos de cuentas de anunciantes, con la esperanza de acabar con el problema. Pero no había manera, y por muchas veces que bloqueáramos esos anuncios, a los pocos días volvían.

Por qué decidimos dejar de mostrar anuncios para proteger a nuestros usuarios

Pero resulta que es imposible detectar todos los anuncios maliciosos, y hace poco estafaron a una tercera persona. Así que decidimos que ya era suficiente y desactivamos todos los anuncios el mes pasado. Eso significa que Kittysplit ya no tiene anuncios (¡yuju!) hasta que encontremos otra solución publicitaria o Adsense arregle el problema. Sabemos que a nadie le gustan los anuncios, pero dependemos de los ingresos por publicidad para que los Kitties gratuitos sigan siendo gratis para ti.

Aunque esto nos cuesta dinero en ingresos por publicidad perdidos, para nosotros es más importante proteger a nuestros usuarios de las estafas de anunciantes sin escrúpulos.

Pero ¿por qué sigue pasando?

La verdadera pregunta es por qué Adsense sigue permitiendo que estos anuncios vuelvan. Van claramente en contra de las políticas de Adsense (Misrepresentation - Misleading ad design): no se permiten anuncios que le pongan difícil al usuario darse cuenta de que está interactuando con un anuncio.

Entonces, ¿por qué Adsense los sigue mostrando? Tendrían que ser bastante fáciles de detectar y bloquear. ¡Por favor! Estamos en 2024 y hablamos de Google, con su IA y todo lo demás. Que cada propietario de una web se pase horas y horas bloqueando los anuncios uno a uno cada vez que vuelven al cabo de uno o dos días no es, obviamente, una solución viable. ¡Google/Adsense tiene que resolver esto por su parte!

Google asegura que usa aprendizaje automático e IA para bloquear anuncios. Pero hasta la IA más rudimentaria de 2024 debería poder detectar sin problema un botonazo verde que dice “CONTINUE”. Y, sin embargo, los anuncios siguen volviendo.

¿Qué te pasa, Adsense?