What is an SDK?
An SDK (Software Development Kit) is a package of code that you add to your game project to use a third-party service. For example, adding the AdMob SDK lets your game show ads from Google. Adding Firebase gives your game analytics, crash reports, and cloud saves — without you having to build a backend server.
Most game SDKs are free to integrate. You only pay (or earn) based on usage — AdMob pays you when players see ads, Google Play Billing takes a cut when players make purchases.
💡 Tip: Only add SDKs you actually need. Every SDK increases your app size and can affect performance. Start with AdMob + Firebase — these two cover 90% of what indie developers need.
Advertising SDKs
📊 Google AdMob SDK Free
The most widely used mobile advertising SDK in the world. AdMob lets you show banner ads, interstitial ads (full-screen between levels), and rewarded video ads (player chooses to watch for a reward). Integrated directly with Google AdSense for payment — Pakistan supported via Payoneer.
Supported platforms: UnityAndroid (Java/Kotlin)iOS (Swift/ObjC)
implementation 'com.google.android.gms:play-services-ads:23.x.x'
How to integrate in Unity:
- Download Google Mobile Ads Unity Plugin from GitHub (googlemobileads/googleads-mobile-unity)
- Import the .unitypackage into your project via Assets → Import Package
- Add your AdMob App ID in Project Settings → Google Mobile Ads
- Create an AdView or InterstitialAd object in your script and call LoadAd()
- Test with test ad unit IDs before going live — never click your own real ads
🎯 Unity Ads SDK Free
Unity's own advertising SDK. It is built into Unity and offers rewarded video ads, interstitial ads, and banner ads. Unity Ads is especially strong for rewarded video — players earn in-game currency for watching a video ad. Very easy to set up from the Unity dashboard.
Supported platforms: UnityAndroidiOS
How to integrate in Unity:
- Open Window → Package Manager in Unity
- Search for "Advertisement Legacy" and install
- Enable Ads in Window → Services → Ads
- Copy your Game ID from the Unity Dashboard
- Initialize with Advertisement.Initialize(gameId, testMode) in your Start()
🔥 IronSource LevelPlay (Mediation) Free
Ad mediation connects multiple ad networks (AdMob, Unity Ads, Meta Audience Network, AppLovin) and in real time picks the highest-paying ad for every impression. This can increase your earnings by 20–50% compared to using a single network. LevelPlay is the recommended mediation platform for Unity developers.
Networks supported: AdMobUnity AdsMetaAppLovinVungle
Setup steps:
- Create a free account at ironsrc.com
- Download the IronSource Unity SDK from their developer portal
- Add your App Key from the IronSource dashboard to your Unity script
- Add adapter SDKs for each network you want to mediate (AdMob adapter, Unity Ads adapter)
- Call IronSource.Agent.init(appKey) in Awake()
Backend & Analytics SDKs
🔥 Firebase SDK (Google) Free Tier
Firebase is Google's all-in-one backend platform for mobile apps and games. The Unity SDK includes Analytics (player behavior tracking), Crashlytics (automatic crash reports), Remote Config (change game settings without an update), Firestore (cloud database), and Authentication (Google/Facebook login). The free Spark plan covers all indie game needs.
Key services: AnalyticsCrashlyticsRemote ConfigFirestoreAuth
How to integrate in Unity:
- Create a project at console.firebase.google.com
- Add your Android app (use your Unity bundle ID)
- Download google-services.json and place in Assets/StreamingAssets/
- Download Firebase Unity SDK from firebase.google.com/docs/unity/setup
- Import only the .unitypackage files for services you need (Analytics, Crashlytics, etc.)
🏆 Google Play Games Services Free
Add leaderboards, achievements, saved games, and multiplayer to your Android game — all tied to Google accounts. Players can see their rank against friends and the world. Achievements add replay value and engagement. Saved games let players continue on different devices.
implementation 'com.google.android.gms:play-services-games-v2:19.x.x'
Setup steps:
- Enable Google Play Games Services in Google Play Console for your app
- Create leaderboards and achievements in the Play Console dashboard
- Download the Play Games Unity Plugin from GitHub (playgameservices/play-games-plugin-for-unity)
- Configure with your App ID from Play Console in the Unity plugin settings
- Call PlayGamesPlatform.Activate() at app start
🛒 Google Play Billing Library Free
Required to implement in-app purchases on Android. Supports one-time purchases (coins, unlocks, remove ads) and auto-renewing subscriptions. Google takes a 15% cut for the first $1M in annual revenue, then 30% above that. Unity has its own IAP plugin that wraps this library.
implementation 'com.android.billingclient:billing:7.x.x'
In Unity (easiest method):
- Open Window → Package Manager → Unity IAP and install
- Enable In-App Purchasing in Window → Services
- Define your products (coins, premium, no-ads) in the Unity IAP catalog
- Implement IStoreListener interface in your purchase manager script
- Test with Google Play's test accounts before publishing
📈 GameAnalytics SDK Free — Unlimited Events
Free game analytics platform specifically designed for game developers. Unlike Firebase Analytics (general purpose), GameAnalytics tracks game-specific events: level completions, progression funnels, resource usage (coins earned/spent), and ad impressions. No cost and no event limits on the free plan. Supports Unity and Godot.
Integration:
- Create a free account at gameanalytics.com
- Add a new game — copy your Game Key and Secret Key
- Download GameAnalytics Unity SDK from Asset Store or GitHub
- Add a GameAnalytics object to your first scene and enter your keys
- Call GA.NewDesignEvent("LevelComplete:Level01") anywhere in your code
Social & Multiplayer SDKs
🌐 PlayFab SDK (Microsoft Azure) Free up to 100K MAU
PlayFab is a complete backend-as-a-service for games. It handles player accounts, inventory, virtual economy (in-game currencies), matchmaking, tournaments, leaderboards, and server-side game logic (cloud scripts). Free for up to 100,000 monthly active users — perfect for indie developers.
Features: Player AccountsEconomyMatchmakingTournamentsCloud Scripts
🎮 Unity Gaming Services (UGS) Free Tier
Unity's own suite of backend services — includes Relay (peer-to-peer multiplayer without a dedicated server), Lobby (player matchmaking rooms), Cloud Save, Remote Config, and Economy. Integrated directly into Unity and works without any third-party accounts.