Firebase SDK for Kotlin Multiplatform

Get Started • Usage • Modules • Manual Installation

The fastest way to add Firebase to your KMP project.

Create a Firebase project at console.firebase.google.com (just the project — no need to add apps, the CLI does it automatically)

brew tap riadmahi/kfire
brew install kfire

kfire init

The CLI automatically:

kfire init

  ✓ firebase-tools installed
  ✓ Authenticated with Firebase
  ✓ Project scanned

  Select your Firebase project
  ● my-app (my-app-12345)

  Which Firebase services do you need?
  ✓ Authentication
  ✓ Firestore
  ○ Storage
  ○ Messaging
  ✓ Analytics
  ○ Remote Config
  ✓ Crashlytics

  How do you want to manage iOS dependencies?
  ● Swift Package Manager (SPM) — Recommended
  ○ CocoaPods

  ✓ Android configured → google-services.json
  ✓ iOS configured → GoogleService-Info.plist
  ✓ SPM configured → Firebase packages added to Xcode
  ✓ Gradle updated → firebase-core, firebase-auth, firebase-firestore, firebase-analytics, firebase-crashlytics

  Setup Complete!

// Initialize once at app startup
FirebaseApp.initialize()

val auth = FirebaseAuth.getInstance()

// Sign in
auth.signInWithEmailAndPassword("user@example.com", "password")

// Create account
auth.createUserWithEmailAndPassword("user@example.com", "password")

// Current user
val user = auth.currentUser

val db = FirebaseFirestore.getInstance()

// Add a city
val city = hashMapOf(
    "name" to "Los Angeles",
    "state" to "CA",
    "country" to "USA",
    "capital" to false,
    "population" to 3900000
)
db.collection("cities").document("LA").set(city)

// Get a city
val document = db.collection("cities").document("LA").get()

// Query cities
val cities = db.collection("cities")
    .whereEqualTo("country", "USA")
    .whereGreaterThan("population", 1000000)
    .get()

val storage = FirebaseStorage.getInstance()
val ref = storage.reference.child("images/mountains.jpg")

// Upload
ref.putBytes(imageData)

// Download URL
val url = ref.downloadUrl

// build.gradle.kts (commonMain)
dependencies {
    implementation("com.riadmahi.firebase:firebase-core:1.0.0")
    implementation("com.riadmahi.firebase:firebase-auth:1.0.0")
    implementation("com.riadmahi.firebase:firebase-firestore:1.0.0")
    // ... add modules you need
}

// Root build.gradle.kts
plugins {
    id("com.google.gms.google-services") version "4.4.2" apply false
}

// App build.gradle.kts
plugins {
    id("com.google.gms.google-services")
}

# Podfile
platform :ios, '15.0'
use_frameworks!

target 'YourApp' do
  pod 'FirebaseCore'
  pod 'FirebaseAuth'
  pod 'FirebaseFirestore'
end

Copyright 2025 Riad Mahi

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

GitHub • Firebase Docs • Kotlin Multiplatform