Open-source multiplayer game server compatible with the RuneScape client
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OpenRS2 is an open-source multiplayer game server and suite of associated tools. It is compatible with build 550 of the RuneScape client, which was released in late 2009.


OpenRS2 requires version 8 or later of the Java Development Kit.

The JDK is required even if a pre-built copy of OpenRS2 is used, as it depends on JDK-only tools, such as jarsigner, at runtime.

Non-free components

OpenRS2 requires the original RuneScape client code, data and location file encryption keys, which we cannot legally distribute.

These files must be manually placed in the nonfree directory (directly beneath the root of the repository), in the following structure:

└── code
    ├── game_unpacker.dat
    ├── jaggl.pack200
    ├── loader_gl.jar
    ├── loader.jar
    ├── runescape_gl.pack200
    └── runescape.jar

The SHA-256 checksums of the correct files are:

7c090e07f8d754d09804ff6e9733ef3ba227893b6b639436db90977b39122590  nonfree/code/game_unpacker.dat
d39578f4a88a376bcb2571f05da1939a14a80d8c4ed89a4eb172d9e525795fe2  nonfree/code/jaggl.pack200
31182683ba04dc0ad45859161c13f66424b10deb0b2df10aa58b48bba57402db  nonfree/code/loader_gl.jar
ccdfaa86be07452ddd69f869ade86ea900dbb916fd853db16602edf2eb54211b  nonfree/code/loader.jar
4a5032ea8079d2154617ae1f21dfcc46a10e023c8ba23a4827d5e25e75c73045  nonfree/code/runescape_gl.pack200
0ab28a95e7c5993860ff439ebb331c0df02ad40aa1f544777ed91b46d30d3d24  nonfree/code/runescape.jar

The nonfree directory is included in the .gitignore file to prevent any non-free material from being accidentally included in the repository.


Run ./gradlew to download the dependencies, build the code, run the unit tests and package it.


OpenRS2 is still in the early stages of development. The current focus is on building underlying infrastructure, such as the deobfuscator, rather than game content. This approach will make it much quicker to build game content in the long run, but it does mean OpenRS2 won't be particularly useful in the short term.

If you're interested in contributing new features, you should discuss your plans in our Discord server first. I have rough plans in my head for the future development direction. Communicating beforehand will avoid the need for significant changes to be made at the code review stage and make it less likely for your contribution to be dropped entirely.

Code style

All source code must be formatted with IntelliJ IDEA's built-in formatter before each commit. The 'Optimize imports' option should also be selected. Do not select 'Rearrange entries'.

OpenRS2's code style settings are held in .idea/codeStyles/Project.xml in the repository, and IDEA should use them automatically after importing the Gradle project.

Kotlin code must pass all of ktlint's tests.

Commit messages

Commit messages should follow the 'seven rules' described in 'How to Write a Git Commit Message', with the exception that the summary line can be up to 72 characters in length (as OpenRS2 does not use email-based patches).

You should use tools like interactive rebase to ensure the commit history is tidy.

Developer Certificate of Origin

OpenRS2 uses version 1.1 of the Developer Certificate of Origin (DCO) to certify that contributors agree to license their code under OpenRS2's license (see the License section below). To confirm that a contribution meets the requirements of the DCO, a Signed-off-by: line must be added to the Git commit message by passing --signoff to the git commit invocation.

If you intend to make a large number of contributions, run the following commands from the repository root to add Signed-off-by: line to all your commit messages by default:

echo -e "\n\nSigned-off-by: $(git config <$(git config>" > .git/commit-template
git config commit.template .git/commit-template

The full text of the DCO is reproduced below:

Developer Certificate of Origin
Version 1.1

Copyright (C) 2004, 2006 The Linux Foundation and its contributors.
1 Letterman Drive
Suite D4700
San Francisco, CA, 94129

Everyone is permitted to copy and distribute verbatim copies of this
license document, but changing it is not allowed.

Developer's Certificate of Origin 1.1

By making a contribution to this project, I certify that:

(a) The contribution was created in whole or in part by me and I
    have the right to submit it under the open source license
    indicated in the file; or

(b) The contribution is based upon previous work that, to the best
    of my knowledge, is covered under an appropriate open source
    license and I have the right under that license to submit that
    work with modifications, whether created in whole or in part
    by me, under the same open source license (unless I am
    permitted to submit under a different license), as indicated
    in the file; or

(c) The contribution was provided directly to me by some other
    person who certified (a), (b) or (c) and I have not modified

(d) I understand and agree that this project and the contribution
    are public and that a record of the contribution (including all
    personal information I submit with it, including my sign-off) is
    maintained indefinitely and may be redistributed consistent with
    this project or the open source license(s) involved.

OpenRS2 does not distribute any of Jagex's intellectual property, and care should be taken to avoid inadvertently including any in contributions.


OpenRS2 uses Semantic Versioning.



OpenRS2 is available under the terms of the ISC license, which is similar to the 2-clause BSD license. The full copyright notice and terms are available in the LICENSE file.