# HorizonSync
\nHorizonSync is a high-performance Fabric 1.21.1 mod designed to keep player data synchronized and secure using MongoDB. Whether you are running a single server looking for data redundancy or a network where player progress must be universal, HorizonSync ensures a seamless experience.<\/p>\n
**Features**<\/p>\n
**Inventory & Equipment Sync**: Full synchronization of the main inventory, armor, offhand items, and Ender Chest.<\/p>\n
**Experience & Stats**: Your XP level, bar progress, health, food, and saturation stay exactly as you left them.<\/p>\n
**Potion Effects**: Active status effects are automatically restored when a player joins the server.<\/p>\n
**High-Performance Persistence**: Features a 3-minute asynchronous auto-save system and a synchronous “force-save” on server shutdown to prevent any data loss.<\/p>\n
**Mod Support**<\/p>\n
HorizonSync is built with deep integration for the most essential Fabric 1.21.1 APIs and mods:<\/p>\n
**Accessories API**: Full synchronization of accessory slots and cosmetics.<\/p>\n
**Trinkets API**: Complete support for all Trinkets slots.<\/p>\n
**Sophisticated Backpacks (Unofficial Fabric Port)**: All backpack contents are serialized and kept in sync.<\/p>\n
**How It Works**<\/p>\n
Unlike traditional methods, HorizonSync leverages MongoDB (NoSQL), allowing for extremely fast and flexible data writing:<\/p>\n
On Join: Data is retrieved from the cloud and injected into the player via synchronized network packets.<\/p>\n
During Gameplay: An asynchronous timer saves changes every 3 minutes without affecting the server’s TPS (Ticks Per Second).<\/p>\n
On Leave\/Shutdown: A final save is performed to ensure every last movement and item is recorded.<\/p>\n
**Getting Started**
\nInstallation: Place the HorizonSync .jar file into the mods folder of your Fabric 1.21.1 server.<\/p>\n
MongoDB Configuration: Upon the first launch, a config file will be generated in the \/config folder. Edit your MongoDB connection string (Local or Atlas) there.<\/p>\n
Connection: Ensure your server’s IP is whitelisted in your database firewall.<\/p>\n
Ready to Go: HorizonSync will automatically create the necessary collections and begin protecting your data.<\/p>\n
**Configuration Options**
\nAll settings are managed via the configuration file in the \/config directory.<\/p>\n
Database Settings
\nuri: Your MongoDB connection string (e.g., mongodb+srv:\/\/user:pass@cluster.mongodb.net\/).<\/p>\n
database: The name of the database (Default: horizonsync).<\/p>\n
collection: The specific collection for player data (Default: playerdata).<\/p>\n
**FAQ**<\/p>\n
Q: Why use MongoDB instead of MySQL?
\nA: MongoDB allows for saving complex objects (like Item NBTs) much more efficiently, reducing lag when processing large or modded inventories.<\/p>\n
Q: What happens if the server crashes?
\nA: Thanks to the 3-minute auto-save system, data loss is minimized. Players will only lose, at most, their last few minutes of progress.<\/p>\n
Q: Is it compatible with Singleplayer?
\nA: HorizonSync is optimized for Dedicated Server environments. It is not recommended for local singleplayer worlds.<\/p>\n
Q: Does it support items from other mods?
\nA: Yes. As long as a mod stores its data within the standard Minecraft NBT, HorizonSync will serialize and sync it correctly.<\/p>\n
**HorizonSync** \u2013 Your data, always on the horizon, always secure.<\/p>\n","protected":false},"excerpt":{"rendered":"
A server side mod that allows synchronising player data across different Fabric servers.<\/p>\n","protected":false},"featured_media":81947,"template":"","meta":{"_minecraft_slug":"horizonsync","_minecraft_project_id":"XqN44qax","_minecraft_author":"soyCQ","_minecraft_license":"Apache-2.0","_minecraft_downloads":12,"_minecraft_follows":1,"_minecraft_client_side":"unsupported","_minecraft_server_side":"required","_minecraft_storage_type":"zip","_minecraft_archive_name":"horizonsync.zip","_minecraft_size_bytes":4294272,"_minecraft_version_count":2,"_minecraft_updated_at":"2026-05-16T12:21:33.942335Z","_minecraft_date_created":"2026-05-16T04:49:24.472474Z","_minecraft_date_modified":"2026-05-16T06:05:41.667539Z","_minecraft_project_url":"https:\/\/modrinth.com\/mod\/horizonsync","_minecraft_icon_attachment_id":81947,"_minecraft_imported_at":"2026-06-04T17:01:35+00:00","_minecraft_import_hash":"15b834543407926ae457fc3b824f0199","_minecraft_versions":"","_minecraft_links":"","_minecraft_gallery":"","_minecraft_api_metadata":""},"mod_category":[97,89,126,92],"mod_loader":[99],"minecraft_version":[37],"class_list":["post-81946","mod","type-mod","status-publish","has-post-thumbnail","hentry","mod_category-fabric","mod_category-game-mechanics","mod_category-management","mod_category-utility","mod_loader-fabric","minecraft_version-1-21-1"],"yoast_head":"\n