Mirror Save

#1 Open Source Unity Networking Library

Project README

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It's only the dreamers who ever move mountains.

Mirror Networking

The #1 free open source game networking library for Unity 2019 / 2020 / 2021.

Used in production by major hits like Population: ONE and many more.

Originally based on UNET: battle tested since 2014 for 8 years and counting!

Mirror is stable, modular & easy to use for all types of games, even small MMORPGs 🎮.

Made in 🇩🇪🇺🇸🇬🇧🇸🇬🇹🇼 with ❤️.


The Server & Client are ONE project in order to achieve maximum productivity.

Simply use NetworkBehaviour instead of MonoBehaviour.

Making multiplayer games this way is fun & easy:

public class Player : NetworkBehaviour
    // synced automatically
    [SyncVar] public int health = 100;
    // lists, dictionaries, sets too
    SyncList<Item> inventory = new SyncList<Item>();
    // server/client-only code
    [Server] void LevelUp() {}
    [Client] void Animate() {}
    void Update()
        // isServer/isClient for runtime checks
        if (isServer) Heal();
        if (isClient) Move();
    // zero overhead remote calls
    [Command]   void CmdUseItem(int slot) {} // client to server
    [Rpc]       void RpcRespawn() {}         // server to all clients
    [TargetRpc] void Hello() {}              // server to one client

There's also NetworkServer & NetworkClient. And that's about it 🤩.

Free, Open & Community Funded

Mirror is free & open source (MIT Licensed).

"Free" as in free beer, and freedom to use it any way you like.

Mirror is funded by Donations from our fantastic community of over 14,000 users!

The top quote is from Fitzcarraldo, which is quite reminiscent of this project.

Getting Started

Get Unity 2019 / 2020 / 2021 LTS, Download Mirror, open one of the examples & press Play!

Check out our Documentation to learn how it all works.

If you are migrating from UNET, then please check out our Migration Guide.

Made with Mirror

Population: ONE

Population: ONE The BigBoxVR team started using Mirror in February 2019 for what eventually became one of the most popular Oculus Rift games.

In addition to 24/7 support from the Mirror team, BigBoxVR also hired one of our engineers.

Population: ONE was recently acquired by Facebook.


nimoyd_smaller Nudge Nudge Games' first title: the colorful, post-apocalyptic open world sandbox game Nimoyd is being developed with Mirror.

Soon to be released for PC & mobile!


dinkum Set in the Australian Outback, Dinkum is a relaxing farming & survival game. Made by just one developer, Dinkum already reached 1000+ "Overwhelmingly Positive" reviews 1 week after its early access release.

James Bendon initially made the game with UNET, and then switched to Mirror in 2019.

A Glimpse of Luna

a glimpse of luna A Glimpse of Luna - a tactical multiplayer card battle game with the most beautiful concept art & soundtrack.

Made with Mirror by two brothers with no prior game development experience.

Sun Haven

sun haven Sun Haven - A beautiful human town, a hidden elven village, and a monster city filled with farming, magic, dragons, and adventure.

After their successful Kickstarter, Sun Haven was released on Steam in 2021 and later on ported to Mirror in 2022.


Inferna MMORPG One of the first MMORPGs made with Mirror, released in 2019.

An open world experience with over 1000 CCU during its peak, spread across multiple server instances.


samutale A sandbox survival samurai MMORPG, originally released in September 2016.

Later on, the Netherlands based Maple Media switched their netcode to Mirror.

Untamed Isles

Untamed Isles The turn based, monster taming MMORPG Untamed Isles is currently being developed by Phat Loot Studios.

After their successful Kickstarter, the New Zealand based studio is aiming for a 2022 release date.


Zooba Wildlife Studio's hit Zooba made it to rank #5 of the largest battle royal shooters in the U.S. mobile market.

The game has over 50 million downloads on Google Play, with Wildlife Studios as one of the top 10 largest mobile gaming companies in the world.


Portals A browser-based metaverse, Portals is an immersive social space where you can explore, make your own, and gather with others.

SCP: Secret Laboratory

scp - secret laboratory_smaller Northwood Studios' first title: the multiplayer horror game SCP: Secret Laboratory was one of Mirror's early adopters.

Released in December 2017, today it has more than 140,000 reviews on Steam.

Naïca Online

Naica Online Naïca is a beautiful, free to play 2D pixel art MMORPG.

The France based team was one of Mirror's early adopters, releasing their first public beta in November 2020.

Laurum Online

Laurum Online Laurum Online - a 2D retro mobile MMORPG with over 500,000 downloads on Google Play.

And many more...

Mirror LTS (Long Term Support)

If you use Mirror in production, consider Mirror LTS!

  • Bug fixes only.
  • Consistent API: update any time, without any breaking features.
  • Lives along side Unity 2019 LTS.
  • Supported from Sept. 2021 to Sept 2022, depending on feedback.

Mirror V46 LTS is available to all GitHub Sponsors.

All sponsors are invited to the Mirror V46 LTS Repository automatically.

Modular Transports

Mirror uses KCP (reliable UDP) by default, but you may use any of our community transports for low level packet sending:


Development & Contributing

Mirror is used in production by everything from small indie projects to million dollar funded games that will run for a decade or more.

We prefer to work slow & thoroughly in order to not break everyone's games 🐌.

Therefore, we need to KISS 😗.

Bug Bounty

A lot of projects use Mirror in production. If you found a critical bug / exploit in Mirror core, please reach out to us in private. Depending on the severity of the exploit, we offer $50 - $500 for now. Rewards based on Mirror's donations, capped at amount of donations we received that month.

Specifically we are looking for:

  • Ways to crash a Mirror server
  • Ways to exploit a Mirror server
  • Ways to leave a Mirror server in undefined state

We are not looking for DOS/DDOS attacks. The exploit should be possible with just a couple of network packets, and it should be reproducible.

Credits / past findings / fixes:

  • 2020, fholm: fuzzing ConnectMessage to stop further connects [#2397]

Credits & Thanks 🙏

🪞 Alexey Abramychev (UNET)
🪞 Alan
🪞 c6burns
🪞 Coburn
🪞 cooper
🪞 FakeByte
🪞 fholm
🪞 Gabe (BigBoxVR)
🪞 imer
🪞 James Frowen
🪞 JesusLuvsYooh
🪞 Mischa
🪞 Mr. Gadget
🪞 NinjaKickja
🪞 Paul Pacheco
🪞 Sean Riley (UNET)

Open Source Agenda is not affiliated with "Mirror" Project. README Source: vis2k/Mirror
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