Drasl

Important

Release notes for Drasl 4.0.0

Drasl is an alternative API server for Minecraft that handles authentication, skins, and capes. You can use it to host Minecraft servers that are completely independent from Mojang's infrastructure. It's designed to be easy to host yourself, but a "reference instance" is hosted at https://drasl.unmojang.org which currently requires a Minecraft account to register.

It's compatible with both authlib-injector and the vanilla Yggdrasil protocol, which means it supports:

• Minecraft launchers that support authlib-injector, such as Fjord Launcher or HMCL
  • Fjord Launcher supports authlib-injector accounts on nearly all versions of Minecraft, from Late Classic onward.
• Vanilla Minecraft servers running version 1.16 or later, via JVM arguments
• Minecraft servers from Late Classic, Alpha, Beta, full release, and onward using Loki
• Minecraft servers running version 1.7.2 or later with authlib-injector

It includes a minimalist web front end for registering and managing accounts.

Background

You've always been able to host your own Minecraft server, but unless you run the server in offline mode, authentication and skins are usually still handled by Mojang's API servers. There are many reasons to host your own API server instead of using Mojang's. Your community might want to:

• Experience the benefits of offline servers without losing skins, encrypted connections, or account security
• Create additional accounts to allow users to have multiple players logged in to a server simultaneously
  • Have a "camera account" spectate your character for content creation
  • Program bots to automate tedious tasks like AFKing, crafting, or even building map art.
• Have skins with transparency, or high-resolution skins (this would require a modded client as well)
• Play Minecraft on a network where Mojang's servers are inaccessible
• Keep your activity private from Mojang. Mojang knows which servers you are active on, when you log on, who else is on those servers, etc. If telemetry is enabled (since 1.18, it cannot be disabled without a mod), they are also notified whenever you load a singleplayer world.
• Serve access tokens that last longer, so you don't run into "Invalid session" errors as often. These errors can be annoying with modpacks that take a long time to restart.
• Opt out of chat reporting
• Have a backup authentication system in case Mojang's servers go down

Features

• Easy to host: a single Go binary plus a few static assets, no runtime dependencies. See doc/installation.md.
• Highly configurable
• Fast, minimalist, and highly-accessible web interface. JavaScript is used only for cosmetic effects and is not required.
• Support nearly all versions of Minecraft (Late Classic through present) when using Fjord Launcher (see doc/usage.md)
• Optional: use "offline" UUIDs. Useful for migrating from online-mode=false servers. See PlayerUUIDGeneration.
• Optional: link with one or more OpenID Connect identity providers (see RegistrationOIDC)
• Optional: allow multiple players per user (see MaxPlayerCount)
• Optional: proxy requests to fallback API servers (see FallbackAPIServers)
  • You can configure your Minecraft server to accept users logged in with either a Mojang account or a Drasl account.
• Optional: disable access token and public key expiry (no more "Invalid session" or "Invalid signature for profile public key")
• Optional: sign player public keys to support chat signing and enforce-secure-profile=true (see SignPublicKeys)
• Optional: allow high-resolution skins (see SkinSizeLimit)
• Optional: allow registering from existing account an another API server (i.e. Mojang's) (see RegistrationUsernamePassword.ImportExistingPlayer, RegistrationOIDC.ImportExistingPlayer, ImportExistingPlayer)
  • Useful if you want to keep your UUID
  • Optional: require a skin challenge to verify ownership of the existing account (see RequireSkinVerification)

Installation

Quick Setup (for Docker on Linux)

1. git clone https://github.com/unmojang/drasl.git
2. sudo cp -RTi ./drasl/example/docker /srv/drasl
3. cd /srv/drasl
4. Fill out config/config.toml according to one of the examples in doc/recipes.md
5. docker compose up -d
6. Set up an HTTPS reverse proxy (using e.g. Caddy or nginx) to localhost:25585.

See doc/installation.md for other setups, including instructions for setting up a reverse proxy.

Configuration

See doc/configuration.md for documentation of the configuration options and doc/recipes.md for common configuration patterns.

Usage

See doc/usage.md for post-installation instructions and guidance on setting up Minecraft clients and servers.

Troubleshooting

doc/troubleshooting.md has some helpful tips, but it's not complete. Feel free to ask for help in our Matrix channel.

API

Drasl has its own API for managing users, players, and invitations. Documentation is here.

Drasl implements the Mojang API, documented here on The Minecraft Wiki:

• Mojang API
• Yggdrasil
• Protocol Encryption

If you find that an API route behaves substantively different than the Mojang API, please file an issue.

Drasl also implements (almost all of) the authlib-injector API at /authlib-injector, to the extent that it differs from Mojang's. The authlib-injector API is documented here (Google Translated to English).

Building

If using Nix (with flakes), simply run nix build.

Otherwise, install build dependencies. Go 1.24 or later is required:

sudo apt install make golang gcc nodejs npm    # Debian
sudo dnf install make golang gcc nodejs npm    # Fedora
sudo pacman -S make go gcc nodejs npm          # Arch Linux

Then build the program with:

make

Run the tests with:

make test

Alternatives

• Blessing Skin with the yggdrasil-api plugin
• Ely.by

FAQ

Why GPL and not AGPL? Isn't this a web application?

Drasl is intended to be self-hosted, customized, and hacked on. If it were licensed under the GNU Affero GPL, any user who tweaks their instance even slightly would be required to publish the changes, or else they would be violating the AGPL. While I'm a strong believer in copyleft, I don't want to place such a burden on the users in this particular case.

Is this legal? Does this break the Minecraft EULA?

See https://github.com/unmojang/drasl/issues/106. enforcement@mojang.com wrote:

The use of a Custom Authentication Server may or may not violate the Minecraft End User License Agreement (EULA), depending on several factors. As long as you ensure that players are using legitimate Microsoft accounts and a valid copy of Minecraft, the use of a Custom Authentication Server may not be problematic.

If you are using Drasl for something beyond personal use (e.g. setting up a large for-profit server), you may want to reach out to enforcement@mojang.com to make sure your use complies with the Minecraft EULA.

Translations

Translating Drasl from English to other languages happens on Hosted Weblate. All contributions are welcome, including translations to new languages and suggestions to improve existing translations.

License

GPLv3