Use 3.2.0 for Minecraft 1.7.2/1.6.4/1.6.2/1.5.2/1.4.7 and older

Certain tasks are impossible to perform with the standard Bukkit API, and may require working with and even modify 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.

Up-to-date developer builds of this project can be acquired at my Jenkins server. These builds have not been approved by the BukkitDev staff. Use them at your own risk.


Please create a ticket with as much information as possible if you experience a problem that has not already been reported. Comments with a huge stack trace will be deleted.

If you need help with the API, please use the developer support forum. If your question cannot be made public for whatever reason (including security bugs), send me a personal message instead.

For server operators

Just download ProtocolLib from the link above. It doesn't do anything on its own, it simply allows other plugins to function.


Source code for a bunch of example programs that use ProtocolLib can be found at this thread on the main support forum.

You may also be interested in PacketWrapper, a library that makes it possible to modify a packet without having to decompile the Minecraft source code.

Finally, for the more advanced users who want to use ProtocolLib if present, but still fall back on their own packet listening system, I recommend taking a look at this thread. I explain where and how to inject code into CraftBukkit in order to intercept sent and received packets yourself.

Maven repository

If you're using Maven, you'll be able to automatically download the JAR, JavaDoc and associated sources from the following repository:

    <name>Comphenix Repository</name>
<!-- And so on -->

This repository contains ProtocolLib, TagHelper and BlockPatcher. You can add any of them as a dependency like so:




Main administrative command. Supports the following sub-commands:

  • config: Reload the configuration file.
  • check: Check for new versions on BukkitDev.
  • update: Check for new versions and automatically download the JAR. The server must be restarted for this to take effect.
  • timings: Toggle measuring the amount of CPU time spent by each plugin. See here for more information.
  • listeners: Display what plugins are using ProtocolLib, and the packet types they are intercepting.

All of these commands require the permission protocol.admin.


/protocol update


Add or remove a debug packet listener. This is useful for plugin authors who just wants to see when a packet is sent, and with what content.

Sub commands:

  • add: Add a packet listener with a given packet ID.
  • remove: Remove one or every packet listener with the given packet IDs.
  • names: Print the name of every given packet ID.

Parameters (in order):

  1. Connection side: Either client or server.
  2. Multiple ID ranges: Can be a single packet ID like 14, or a range like 10 - 15. Defaults to 0 - 255 if not specified.
  3. Detailed: If TRUE, prints the full packet content.


/packet add client 10-13 true

Remove all listeners:

/packet remove client
/packet remove server

Note that this command should rarely be used on a production server. Listening to too many packets may crash the server.


The filter system (introduced in 2.4.1) uses the built in JavaScript interpreter in JVM 6 (Rhino) to extend the packet command with filtering capabilities - it is now possible to, say, only print entity metadata packet events (packet add server 40) for a given entity ID:

> packet add server 40 true
Added listener ListeningWhitelist{priority=MONITOR, packets=[40]}
> filter add entity_filter 40
Enter filter program ('}' to complete or CANCEL):
function(event, packet) {
>   return packet.a == 1000; 
Added filter entity_filter.

This should be much more convenient than having to compile a test plugin and reload the whole server. Note that this feature is disabled by default for security reasons. To enable it, add "debug: true" to config.yml.


A small set of configuration options are available:

Global section



auto updater.notifytrueInform any player with the permission when a new version of ProtocolLib is out.
auto updater.downloadtrueAutomatically download and install the newest version of ProtocolLib. The installation will take effect when the server restarts.
auto updater.delay43200The number of seconds between each check for a new update.
auto updater.last0This simply records the last time (in seconds since 01.01.1970) an update check was performed. Set it to 0 to force a new update check.
metricstrueIf TRUE, ProtocolLib will publish anonymous usage data to Set it to FALSE to opt-out.
background compilertrueIf TRUE, ProtocolLib will try and improve performance by replacing reflection with compiled code on-the-fly.
ignore version checkNoneForce ProtocolLib to start for a specified Minecraft version, even if it is incompatible.
suppressed reportsNoneIf any error or warning report is present in this list, they will not appear in the console or the log.

For more information, take a look at the default configuration file.

Tutorial for developers

See this page for more information.


One of the main goals of this project was to achieve maximum compatibility with CraftBukkit. And the end result is quite good - in tests I successfully ran an unmodified ProtocolLib on CraftBukkit 1.8.0, and it should be resilient against future changes. It's likely that I won't have to update ProtocolLib for anything but bug and performance fixes.

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.

Plugins that appear to be compatible

Plugins known to be compatible

  • SpoutPlugin

Plugins using ProtocolLib

Inactive projects

Please let me know if you want me to add your plugin to this list. :)


This plugin uses MCStats to generate and publish anonymous aggregate usage statistics, but you can easily opt-out by setting metrics in config.yml to false.

If enabled, the following is sent every ten minutes:

  • Metrics revision version (currently 6).
  • Server's GUID
  • Players currently online (not max player count)
  • Server version string (the same version string you see in /version)
  • Current version of ProtocolLib
  • The name of every plugin that registers a packet listener in ProtocolLib.


I would like to thank everyone who has donated to ProtocoLib. I really appreciate it. :)



ProtocolLib Statistics

Note: Create a ticket if you're having problems. Don't post stack traces in the comments.

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  • Avatar of CommodoreAlpha CommodoreAlpha Dec 04, 2013 at 13:46 UTC - 1 like

    @pilvimaa: Go

    While I do agree that updates and such take time, and that donations don't magically speed things up, they're always helpful encouragement.

    @Swords761: Go

    The sarcasm is actually pretty subtle; when I read it at first, it was a bit discerning. However, the sentence that most gives it away is when he asks "Anyone recommend a good plugin that edits packets, is backwards compatible, offers great support and is easy and simple to use?" There is "hidden praise" for the plugin here; the rhetorical question also implies that "No, there is no other plugin out there remotely like, or nearly as great as ProtocolLib".

    Last edited Dec 04, 2013 by CommodoreAlpha

    Sure, I'd love to include my server IP here. But it's under construction, and I wouldn't want to get sued for players wandering inside and getting hit by a random beam of steel floating about. And no, I doubt plugins would make very good lawyers either. I've never seen a plugin that forced you to sign a contract do so well.

  • Avatar of therennon therennon Dec 04, 2013 at 10:31 UTC - 0 likes

    Once there was a plugin that prevented thousands of servers updated to version 1.7.2. hahahah

    Tranquility boys and girls, will update when possible.


  • Avatar of pilvimaa pilvimaa Dec 04, 2013 at 07:49 UTC - 1 like

    It isn't about getting paid or delaying on purpose. It just takes a bit of time to update because it's not magic.

    aadnk is working on it and will release the update when it's ready in a few days.

    There is no point in releasing a half assed half working plugin that would most likely crash people's servers, so... It also takes time to verify that everything works ok, usually a lot more then the actual coding.

    Last edited Dec 04, 2013 by pilvimaa
  • Avatar of add5tar add5tar Dec 04, 2013 at 05:33 UTC - 1 like

    @Swords761: Go

    Considering who made the comment and the heavy dependency on ProtocolLib for many of their own plugins, it's safe to say the sarcasm rating was quite high ;)

  • Avatar of Swords761 Swords761 Dec 04, 2013 at 05:09 UTC - 0 likes

    @libraryaddict: Go

    I sincerely hope this was some elaborate form of comment trolling.


  • Avatar of libraryaddict libraryaddict Dec 04, 2013 at 04:57 UTC - 2 likes

    He did half of a update and pushed to github.

    WTF? Why didn't he do the whole update!!! Its only a few thousand codes. Not that hard. I do that easily!! This is bs. I'm taking my business somewhere else.

    Anyone recommend a good plugin that edits packets, is backwards compatible, offers great support and is easy and simple to use???


  • Avatar of Tzeentchful Tzeentchful Dec 03, 2013 at 22:46 UTC - 2 likes

    Thought I would help by donating $15 and to say thanks for all your work. Keep up the work on the 1.7.2 update!

  • Avatar of jamescowens jamescowens Dec 03, 2013 at 21:42 UTC - 1 like

    I donated $50.00. Doing a small part to help.

  • Avatar of xiTzJardix xiTzJardix Dec 03, 2013 at 19:03 UTC - 0 likes

    @ProMiner909: Go

    me too


  • Avatar of defineci00 defineci00 Dec 03, 2013 at 18:58 UTC - 0 likes

    @Archmohaa: Go

    yes it is


Date created
Oct 05, 2012
Last update
Apr 17, 2014
Development stage
  • enUS
GNU General Public License version 2 (GPLv2)
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