rbxdev-ls

A fast, full-featured language server for Roblox Luau development.

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Features

Intelligent Completions

• Full Roblox API — all classes, methods, properties, and events
• Sunc executor functions out of the box
• Live game tree completions when connected to an executor
• Auto-import suggestions from your workspace modules
• Context-aware table field completions

Type Checking

• Bidirectional type inference
• --!strict, --!nonstrict, and --!nocheck modes
• All Roblox datatypes (Vector3, CFrame, Color3, UDim2, etc.)
• Generics, unions, intersections, and optional types
• Inheritance-aware class typing

Navigation

• Go to definition
• Find all references
• Rename symbol across files
• Document symbol outline

Editor Goodies

• Hover docs with full type signatures
• Signature help while typing function args
• Semantic highlighting
• Inlay hints for inferred types
• Color picker for Color3 values
• StyLua formatting integration

Workspace Integration

• Rojo project file support
• DataModel path resolution
• Automatic require path generation

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Installation

VS Code

cd vscode
bun install
bun run package
# Install the .vsix file

Or grab it from the releases page.

Standalone

bun install
bun run build

The server speaks LSP over stdio — plug it into any editor that supports language servers.

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Usage

Drop a mode comment at the top of your file:

--!strict

local Players = game:GetService("Players")
local player = Players.LocalPlayer
local character = player.Character or player.CharacterAdded:Wait()

-- Full type inference and completions from here

Executor Bridge

The language server can connect to Roblox executors for live game data. When an executor connects to port 21324:

• Get completions from the actual game tree
• See real Instance children and properties
• No more guessing what exists at runtime

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Project Layout

src/
├── @core/        # LSP server setup
├── @parser/      # Luau lexer & parser
├── @typings/     # Type system
├── @definitions/ # Roblox API types
├── @lsp/         # All the LSP handlers
├── @executor/    # Runtime bridge
└── @workspace/   # Rojo support

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Development

bun run dev        # Watch mode
bun run build      # Production build
bun run type-check # Check types
bun run lint       # Lint & fix
bun run format     # Prettier

Updating Roblox API

bun run fetch-api

Pulls the latest API dump from Roblox and regenerates type definitions.

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Contributing

PRs welcome. If you're adding a feature, write a test for it.

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License

MIT