Lync

Typed buffer networking for Roblox, in Luau and roblox-ts.

You declare packets, queries and replicated sets once, in a module both sides require. Lync packs every value to the bit from that schema and infers your handler types from it. Everything sent in a frame is batched per client when you flush.

ReplicatedStorage/Net.luau

local ReplicatedStorage = game:GetService("ReplicatedStorage")
local Lync = require(ReplicatedStorage.Lync)

return Lync.define("game", {
    Chat = Lync.packet(Lync.str(1, 200)),

    Sell = Lync.query(Lync.enum({ "sword", "shield" }), Lync.int(0, 1000)),

    Scores = Lync.replicate(Lync.struct({
        name = Lync.str(1, 20),
        score = Lync.int(0, 1000000),
    })),
})

ServerClient

local Players = game:GetService("Players")
local ReplicatedStorage = game:GetService("ReplicatedStorage")
local RunService = game:GetService("RunService")
local Lync = require(ReplicatedStorage.Lync)
local Net = require(ReplicatedStorage.Net)

local PRICES = { sword = 100, shield = 60 }

Net.Chat:onServer(function(text, player)
    Net.Chat:fireClient(Lync.except(player), text)
end)

Net.Sell:onServer(function(item, player)
    return PRICES[item]
end)

Lync.start()
RunService.PostSimulation:Connect(function()
    Lync.flush()
end)
game:BindToClose(Lync.close)

local function joined(player: Player)
    Net.Scores:add(player.UserId, { name = player.Name, score = 0 })
end

Players.PlayerAdded:Connect(joined)
for _, player in Players:GetPlayers() do
    joined(player)
end
Players.PlayerRemoving:Connect(function(player)
    Net.Scores:remove(player.UserId)
end)

local ReplicatedStorage = game:GetService("ReplicatedStorage")
local RunService = game:GetService("RunService")
local Lync = require(ReplicatedStorage.Lync)
local Net = require(ReplicatedStorage.Net)

Net.Chat:onClient(function(text)
    print(text)
end)

Net.Scores:onChanged(function(id, record)
    print(record.name, record.score)
end)

Lync.start()
RunService.PostSimulation:Connect(function()
    Lync.flush()
end)

Net.Chat:fireServer("hello")

local ok, price = Net.Sell:request("sword")
if ok then
    print("sold for", price)
end

record.score is typed number with no annotation, because the schema says so.

Where to go

Page	Answers
Getting started	How do I install Lync and wire both sides?
Codecs	How do I describe a value, and what does it cost?
Packets	How do I send a one-way message?
Queries	How do I ask for an answer?
Sets	How do I replicate state, and to whom?
Limits	What can't I do, and what can I change?