SKILL.md
ESX Framework Development
Complete guide for developing with ESX Legacy Framework — the most trusted FiveM roleplay framework since 2017.
When to use
- Creating or editing ESX resources/scripts
- Working with player data (xPlayer, PlayerData)
- Implementing jobs, economy, inventory, or weapon systems
- Using ESX client/server functions, callbacks, or events
- Questions about ESX best practices and optimization
How to use
Read individual rule files for detailed explanations and examples:
- rules/core-concepts.md — ESX architecture, PlayerData, xPlayer object, framework initialization
- rules/client-functions.md — Client-side ESX functions, UI systems, player state management
- rules/server-functions.md — Server-side functions, player retrieval, callbacks, triggers
- rules/xplayer-methods.md — xPlayer object methods: money, items, weapons, inventory, jobs, metadata
- rules/jobs-economy.md — Job system, salaries, accounts (money/bank), society management
- rules/inventory-items.md — Inventory system, item management, usable items, weight calculations
- rules/weapons-loadout.md — Weapon system, loadout, components, ammo, tints
- rules/events-callbacks.md — ESX events, server callbacks, client callbacks, secure net events
- rules/best-practices.md — ESX coding standards, optimization, security, naming conventions
- rules/reference-links.md — Official ESX documentation links
Key principles
- Always check for nil —
if xPlayer then ... endbefore using xPlayer - Use ESX.GetPlayerFromId — Standard player retrieval:
local xPlayer = ESX.GetPlayerFromId(source) - Wait for player load — Check
ESX.IsPlayerLoaded()on client before accessing PlayerData - Never trust client — Validate all data server-side, use SecureNetEvent for client events
- Follow ESX patterns — Use ESX functions instead of reinventing (callbacks, notifications, etc.)
- Optimize loops — Cache player objects, avoid unnecessary GetPlayerFromId calls
- Use camelCase — Follow Lua naming:
myVariable,MyGlobalFunction,MY_CONSTANT - Minimal globals — Keep variables local unless they need global scope
- Use oxlib for UI — Prefer oxlib for menus, dialogs, notifications, progress bars instead of ESX UI