Easiest Unity Netcode for Game Developers
Game development is complex, its components often numerous and as intricate to understand as they are named. In this guide, we aim to demystify the complexities of game services, tools and technologies for beginners and indie developers.
Starting with the all-mighty important for multiplayer games: netcode.
Understanding netcode is crucial for creating engaging and seamless multiplayer experiences. Let's cover what it is, why it matters, and the easiest and most effective netcode implementations available in Unity today.
What is Netcode?
Netcode is a term that encapsulates the networking aspect of a video game, particularly in multiplayer settings. It's the technology responsible for the exchange of data between players' devices and game servers, which is called “synchronization”, and ensures that actions performed by one player are reflected immediately and precisely in another player's game environment.
This synchronization is challenging due to varying latencies and connection qualities players around the globe experience. Effective netcode accounts for dated or suboptimal player machine setups, striving to offer a fair, smooth gaming experience.
Netcode also plays a vital role in maintaining game integrity by handling data securely.
Choosing the Right Netcode for Your Game
Selecting the appropriate netcode is a pivotal decision in game development. The choice largely depends on your game's genre, gameplay mechanics, and the expected player base.
Client-Server Models vs. Peer-to-Peer (P2P): P2P is often used in smaller, less latency-sensitive and generally non-competitive games. It connects players directly, reducing the need for a central server. In contrast, the client-server model, where players connect to a central server, is more suited for larger, competitive games requiring a third-party server authority to enforce game rules and security. However, P2P in particular introduces security concern game developers need to be aware of when choosing it as an architecture.
Consider Game Genre: Fast-paced games like shooters demand a more robust netcode to handle quick player actions and ensure all clients remain synchronized, whereas strategy games can be more forgiving and utilize predictive techniques to enable sessions with higher latencies.
Scalability: Anticipate your game's growth. A scalable netcode can handle an increasing number of players without compromising performance or ramping up a massive bill with your hosting provider.
Security and Fair Play: Ensure your netcode can thwart common cheats and hacks to maintain a fair playing field.
Building a Multiplayer Game: Using Netcode as a First Time Experience
For beginners, Unity offers a user-friendly platform to implement netcode called Netcode for GameObjects. Let's break down the basic steps:
Understanding Unity's Netcode: Unity provides a robust set of tools for networking. Familiarize yourself with Unity's networking components, such as NetworkManager and NetworkIdentity.
Setting Up a Basic Network: Start by creating a simple client-server setup. Unity's tutorials and documentation are great resources for the initial steps.
Synchronizing GameObjects: Learn to synchronize game objects across different clients. This includes player characters and interactive elements in the game world.
Handling Player Inputs: Ensure that player inputs are effectively communicated and reflected across all clients.
Testing: Regularly test your netcode under various network conditions to ensure reliability and performance.
Stepping Up: The Better Netcode Alternatives
Unity for GameObjects is well documented to have hard limitations. Specifically, three community-made netcode solutions have risen to prominence and are each bringing meaningful improvements to game developers. Two are long-established open-source projects: the 10-year veteran Mirror Networking and Fish-Net Networking. The third, PurrNet, is a newer entrant gaining traction for its developer-friendly design.
Mirror Networking
Mirror is the longest-standing open-source networking library for Unity, originating from the now-deprecated UNET that Unity shipped natively. It runs on a client-server topology with server authority, which means the server is the source of truth for game state — a prerequisite for any game that needs meaningful anti-cheat protection.
Mirror is OSI-certified open source, widely documented, and has a large community. It ships with support for lag compensation (useful for hit registration in shooters), Area of Interest (for controlling which clients receive updates about which objects), Steam and Epic transports, WebSocket support for WebGL builds, and Multiplex Transport so a single server can accept clients on different transports simultaneously.
A few things worth knowing before you commit. Mirror uses a singleton API design, meaning only one instance of the networking core can run per executable. That's fine for most games, but limits certain advanced architectures. There is also no formal Long-Term Support (LTS) track: the API has historically changed at a pace that can require code updates between versions. For a game in active development, that means keeping an eye on the changelog.
Well-known games using Mirror Networking include Population: ONE, Zoomba (100 million downloads on Google Play), and Unleashed from former World of Warcraft developers.
PurrNet
PurrNet is a free, open-source Unity networking library built by developers who felt that existing solutions fight against Unity's natural workflow rather than embracing it. The core idea is straightforward: if you already know how to use Unity and C#, you should be able to build multiplayer games without learning a completely different way of working.
A few things stand out. First, spawning and despawning work exactly as they do in Unity. You call Instantiate() and Destroy(), and PurrNet handles the networking. No special spawn calls, no extra steps. Second, authority is controlled through a single Network Rules scriptable object rather than baked into your game code, meaning you can prototype with full client authority and lock things down to server authority later without rewriting anything. Third, there is no baking step. Scene IDs are calculated at runtime from hierarchy order, which removes an entire class of version control conflicts and mysterious build issues that developers on other solutions regularly run into.
On the RPC side, PurrNet supports generic, static, and awaitable RPCs. Awaitable RPCs let you call a method on the server and await a return value directly, similar to how async/await works in regular C#. It also ships with a persistent player data system (its "cookie" system) that lets the server recognize a reconnecting player as the same person without any custom code.
PurrNet is 100% free with no paid tier. There is no revenue sharing, no up-front cost, and no core features locked behind a paywall.
Edgegap has a full integration tutorial for PurrNet that walks through getting your Unity project connected to dedicated game servers:
Fish Networking ("Fish-Net")
Fish-Net Networking is a networking technology designed for online multiplayer games, emphasizing adaptability and scalability. It has become the go-to recommendation for developers who want community-maintained tooling that keeps pace with more demanding game types.
Where Mirror keeps things straightforward, Fish-Net affirms it goes further. It ships with client-side prediction for both transforms and rigidbodies — the kind of feature that matters when you're building fast-paced competitive games where movement needs to feel immediate while the server stays authoritative. Lag compensation is available (as a paid feature) for accurate hit registration regardless of player latency. For larger game worlds, Area of Interest support lets you control exactly which clients receive updates about which objects, keeping bandwidth in check.
Fish-Net also has a formal Long-Term Support track and a stability guarantee on API updates, meaning you can upgrade versions without expecting your existing code to break. It uses an instanced API design rather than a singleton, which allows a single executable to act as multiple servers or connect to multiple servers simultaneously. That matters for more advanced architectures.
A few other practical details: Fish-Net supports allocation-free transports for better garbage collection performance at scale, stacked and additive scenes (useful for instanced dungeons or separate game rooms on a single server), and Unity Transport and Photon Transport out of the box alongside Steam and Epic.
The benefits of Fish-Net Networking include enhanced scalability, reduced server load, and increased robustness in handling fluctuations in player numbers.
Games using Fish-Net Networking include Arcadius, Fight Action Sandbox, Reign of Dwarf, Cat Warfare, Skygard Arena, and many more both in release and in production.
Netcode Best Practices
Optimize for Latency: Implement techniques like lag compensation and prediction to counteract latency issues.
Security Measures: Regularly update your netcode to protect against new vulnerabilities and cheats. Attackers love to target the most popular libraries as they expose the most users.
Scalable Architecture: Design your netcode to be scalable, accommodating an increasing number of players smoothly. Minimize the number of objects and properties that need to be synchronized, and consider the worst possible scenario your game design permits.
Feedback Loops: Implement feedback mechanisms to monitor performance and player experiences, allowing for continuous improvement.
Test often: Implement your end-to-end tests and load tests in a way that makes them easy to re-run whenever you make any major changes to your game, so you have confidence that your next update doesn't bring you bad reviews.
Conclusion
Mastering netcode is a journey filled with challenges and learning opportunities.
By choosing the right netcode, understanding Unity's tools, following best practices, and utilizing available resources, you can create engaging and smooth multiplayer experiences.
Following your selection of netcode, the next step to getting your game online will be to decide on hosting. Fortunately, Edgegap has integrations within popular plugins including Mirror, Fish-Net, and PurrNet. Watch the videos above, or head over to their respective documentation.
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Feature comparison data for Mirror and Fish-Net is sourced in part from a community-maintained Unity Networking Solutions spreadsheet (the spreadsheet was last reviewed April 2025, no longer actively maintained).
Written by
Vincent Archambault, CSO at Edgegap
