# Practical Kotlin Multiplatform: Implementing the Firebase Sign-up Operation with Ktor

DevFeed: [Practical Kotlin Multiplatform: Implementing the Firebase Sign-up Operation with Ktor](<https://devfeed.tech/articles/practical-kotlin-multiplatform-implementing-the-firebase-sign-up-operation-with-ktor-25189.md>)

Original publisher: [Read original article](<https://joebirch.co/android/practical-kotlin-multiplatform-implementing-the-firebase-sign-up-operation-with-ktor/>)

Author: hitherejoe

Published: 2026-07-26T07:37:53Z

Content type: tutorial

Language: en

Sources: [Joe Birch](<https://devfeed.tech/sources/joe-birch.md>)

Topics: [Kotlin Multiplatform](<https://devfeed.tech/topics/kotlin-multiplatform.md>), [Firebase](<https://devfeed.tech/topics/firebase.md>), [Ktor](<https://devfeed.tech/topics/ktor.md>), [Authentication](<https://devfeed.tech/topics/authentication.md>), [Android](<https://devfeed.tech/topics/android.md>), [interfaces](<https://devfeed.tech/topics/interfaces.md>), [iOS](<https://devfeed.tech/topics/ios.md>), [Exception](<https://devfeed.tech/topics/exception.md>)

Tags: [android](<https://devfeed.tech/tags/android.md>), [authentication](<https://devfeed.tech/tags/authentication.md>), [code](<https://devfeed.tech/tags/code.md>), [exception](<https://devfeed.tech/tags/exception.md>), [firebase](<https://devfeed.tech/tags/firebase.md>), [interfaces](<https://devfeed.tech/tags/interfaces.md>), [ios](<https://devfeed.tech/tags/ios.md>), [jetpack-compose](<https://devfeed.tech/tags/jetpack-compose.md>), [kotlin](<https://devfeed.tech/tags/kotlin.md>), [kotlin-multiplatform](<https://devfeed.tech/tags/kotlin-multiplatform.md>), [ktor](<https://devfeed.tech/tags/ktor.md>), [multiplatform](<https://devfeed.tech/tags/multiplatform.md>)

## AI overview

A tutorial on implementing a Firebase sign-up API request in a Kotlin Multiplatform application using Ktor. It defines an authentication repository interface and service implementation for Android and iOS clients, including API key, email, and password parameters and exception handling.

## Source excerpt

This post is part four of a series adapted from Practical KMP, my book on building production Kotlin Multiplatform apps for Android and iOS. Part two built the authentication remote store and modelled its response. Implementing the Sign-up Endpoint Now that we've created the models for receiving back an authentication response, it's time for us... Continue reading ->