NexusCore — RPG Framework for Survival Servers

Turn any Survival or SMP server into a fully-featured RPG — without replacing a single vanilla mechanic.

NexusCore is a lightweight, modular RPG framework for Paper 1.21+. It provides the foundation that addon plugins build on: a persistent stat system, skill engine, class framework, and a clean public API. Install NexusCore once, then layer as many addons as you like.

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Features

Player Stats

Every player has a full set of RPG stats that persist across sessions:

• Level & XP — quadratic XP curve, configurable per-level bonuses
• HP & Mana — fully synced with Bukkit's health bar
• Attack Power, Defense, Stamina — ready for addons to use
• Unspent Stat Points — distribute freely with /nexus spend

Class System

Three built-in classes with unique stat multipliers — more via addons:

Class	HP	Mana	Attack	Defense
Warrior	×1.4	×0.6	×1.3	×1.5
Mage	×0.8	×1.8	×1.2	×0.7
Archer	×1.0	×1.0	×1.4	×0.9

Skill Engine

A full skill registry with cooldown tracking and mana costs. Addons register their own active and passive skills in one line. Players activate skills through addon-defined triggers (items, keybinds, etc.).

Storage

Choose between YAML (zero setup) or MySQL (recommended for larger servers). Switch with one line in config.yml. MySQL saves run async to keep your TPS clean.

Action Bar

A live HP and mana bar shown to every player above the hotbar — always in sync, no config needed.

PlaceholderAPI Support

14 placeholders available for scoreboards, tab lists, and holograms: %nexuscore_level% · %nexuscore_class_name% · %nexuscore_hp% · %nexuscore_mana% · and more.

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For Addon Developers

NexusCore exposes a clean public API. Register skills, classes, and listen to RPG events in a few lines of code:

NexusCoreAPI api = NexusCore.getInstance().getAPI();

// Register a custom skill
api.registerSkill(new FireballSkill());

// Register a custom class
api.registerClass(new RPGClass("PALADIN", "Paladin", 1.3, 1.2, 1.0, 1.4, "Holy warrior."));

// Give XP to a player
api.giveExperience(player, 500);

Custom events: NexusLevelUpEvent, NexusClassChangeEvent Utility classes: ChatUtil, ItemBuilder

Full addon documentation is included in the download.

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Commands

Command	Description
/nexus stats [player]	View RPG stats
/nexus spend	Spend a stat point
/nexus setclass	Set your class
/nexus classes	List all classes
/nexus skills	List registered skills
/nexus givexp	Give XP (admin)
/nexus reset [player]	Reset RPG data (admin)
/nexus reload	Reload config (admin)

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Requirements

• Paper 1.21+
• Java 21+
• PlaceholderAPI (optional)

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NexusCore is a developer framework — it adds no gameplay by itself. Gameplay comes from addons that depend on it.