SyncBridge

ModSync is a Forge 1.20.1 mod that lets a Minecraft server distribute required mods and client-side content to connecting players while the server is already running.

Instead of sending players a separate modpack link and asking them to reinstall everything by hand, ModSync compares the client against the server manifest, downloads the missing files, removes outdated managed files, and guides the player through restart steps only when a restart is actually required.

Features

• Synchronizes server-required mods from the active server mods folder.
• Distributes client-side content such as resource packs, shader packs, configs, and optional client files from a dedicated sync repository.
• Verifies downloaded files with SHA-256 hashes.
• Cleans up obsolete managed files without blindly deleting locally replaced content.
• Supports pre-join synchronization and post-login handshake validation.
• Works with either direct embedded HTTP delivery or a reverse proxy setup.

Designed For Real Servers

ModSync is aimed at private servers, curated communities, and modded environments where the server owner wants tighter control over what clients actually run.

Recent stability work includes:

• safer handling for large or slow remote file hosts
• fallback when a manifest still points to an unreachable public download base URL
• more reliable dedicated-server handshake behavior after pre-join sync
• staged self-update support for the client ModSync jar
• stricter packet and manifest validation to avoid malformed sync states

Supported Content Layout

Server mods are synchronized directly from the server mods directory.

Additional client-side content can be synchronized from a dedicated sync repository, for example:

• resourcepacks
• shaderpacks
• configs
• optional_client

Requirements

• Minecraft 1.20.1
• Forge 47.4.18 or newer
• Java 17

Notes

• ModSync is not a generic CurseForge modpack installer. It is a server-driven synchronization layer for Forge servers.
• The project focuses on controlled synchronization, safe cleanup behavior, and practical deployment on live servers.
• Source repository and release history are maintained by the project owner.