Provides read and write access to the Minecraft protocol with Bukkit.
Go to file
Dan Mulloy 2cad996252
fix: gracefully fail for unknown protocols
Fixes #3012
Fixes #3001
Fixes #2994
2024-06-14 14:00:59 -05:00
.github Add support for 1.20.5/1.20.6 part 2 (#2910) 2024-05-06 19:02:15 +02:00
TinyProtocol Convert tabs to spaces 2023-05-12 10:35:34 -04:00
gradle/wrapper Start 1.20.4 update 2023-12-09 15:56:45 -06:00
src fix: gracefully fail for unknown protocols 2024-06-14 14:00:59 -05:00
.gitattributes Normalize line endings to LF 2022-12-07 13:52:09 -05:00
.gitignore Update version to 5.1.0 for release 2023-08-05 11:31:59 -05:00
License.txt Adding GPL v2 license information to every file. 2012-10-10 22:18:11 +02:00 Update version to 5.1.1 for development 2023-08-05 13:58:29 -05:00
build.gradle 1.21 2024-06-13 18:01:40 -05:00 Migrate to Gradle (#2319) 2023-04-15 16:09:15 -05:00
gradlew update dependencies & gradle (#2589) 2023-10-25 07:07:58 -05:00
gradlew.bat Migrate to Gradle (#2319) 2023-04-15 16:09:15 -05:00
jitpack.yml dependency updates (#1790) 2022-07-30 20:01:11 -04:00
settings.gradle Migrate to Gradle (#2319) 2023-04-15 16:09:15 -05:00


Certain tasks are impossible to perform with the standard Bukkit API, and may require working with and even modifying Minecraft directly. A common technique is to modify incoming and outgoing packets, or inject custom packets into the stream. This is quite cumbersome to do, however, and most implementations will break as soon as a new version of Minecraft has been released, mostly due to obfuscation.

Critically, different plugins that use this approach may hook into the same classes, with unpredictable outcomes. More than often this causes plugins to crash, but it may also lead to more subtle bugs.



ProtocolLib is built with Gradle. If you have it installed, just run ./gradlew build in the root project folder. Other gradle targets you may be interested in include clean, test, and shadowJar. shadowJar will create a jar with all dependencies (ByteBuddy) included.

A new API

ProtocolLib attempts to solve this problem by providing an event API, much like Bukkit, that allows plugins to monitor, modify, or cancel packets sent and received. But, more importantly, the API also hides all the gritty, obfuscated classes with a simple index based read/write system. You no longer have to reference CraftBukkit!

Using ProtocolLib

To use this library, first add ProtocolLib.jar to your Java build path. Then, add ProtocolLib as a dependency or soft dependency to your plugin.yml file like any other plugin:

depend: [ ProtocolLib ]

You can also add ProtocolLib as a Maven dependency:



Or use the maven dependency with gradle:

repositories {
    maven { url "" }

dependencies {
    compileOnly 'com.comphenix.protocol:ProtocolLib:5.1.0'

Then get a reference to ProtocolManager in onLoad() or onEnable() and you're good to go.

private ProtocolManager protocolManager;

public void onLoad() {
    protocolManager = ProtocolLibrary.getProtocolManager();

To listen for packets sent by the server to a client, add a server-side listener:

// Disable all sound effects
protocolManager.addPacketListener(new PacketAdapter(
) {
    public void onPacketSending(PacketEvent event) {

It's also possible to read and modify the content of these packets. For instance, you can create a global censor by listening for Packet3Chat events:

// Censor
protocolManager.addPacketListener(new PacketAdapter(
) {
    public void onPacketReceiving(PacketEvent event) {
        PacketContainer packet = event.getPacket();
        String message = packet.getStrings().read(0);

        if (message.contains("shit") || message.contains("damn")) {
            event.getPlayer().sendMessage("Bad manners!");

Sending packets

Normally, you might have to do something ugly like the following:

PacketPlayOutExplosion fakeExplosion = new PacketPlayOutExplosion(
    new ArrayList<>(),
    new Vec3D(
        player.getVelocity().getX() + 1,
        player.getVelocity().getY() + 1,
        player.getVelocity().getZ() + 1

((CraftPlayer) player).getHandle().b.a(fakeExplosion);

But with ProtocolLib, you can turn that into something more manageable:

PacketContainer fakeExplosion = new PacketContainer(PacketType.Play.Server.EXPLOSION);
    .write(0, player.getLocation().getX())
    .write(1, player.getLocation().getY())
    .write(2, player.getLocation().getZ());
fakeExplosion.getFloat().write(0, 3.0F);
fakeExplosion.getBlockPositionCollectionModifier().write(0, new ArrayList<>());
fakeExplosion.getVectors().write(0, player.getVelocity().add(new Vector(1, 1, 1)));

protocolManager.sendServerPacket(player, fakeExplosion);


One of the main goals of this project was to achieve maximum compatibility with CraftBukkit. And the end result is quite flexible. It's likely that I won't have to update ProtocolLib for anything but bug fixes and new features.

How is this possible? It all comes down to reflection in the end. Essentially, no name is hard coded - every field, method and class is deduced by looking at field types, package names or parameter types. It's remarkably consistent across different versions.