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Source: Roblox Creator Hub · CC BY 4.0 · View source · Code samples: MIT Imported 2026-10-03. Formatting adapted for this site.

LogService

Inherits from: Instance → Object

LogService allows you to log structured log entries and read outputted text.

Template Syntax

Methods that accept a context table support {key} template placeholders in the message string. To include a literal brace character in the output, use double braces: {{ produces a literal { and }} produces a literal }.

local LogService = game:GetService("LogService")

LogService:Info("Value = {{result}}: {val}", {val = 42})
-- Output: "Value = {result}: 42"

Context Values

The context table accepts any value type. Non-serializable values are automatically converted to strings in the stored context:

• Instances are stored as their full path (e.g., "Workspace.MyModel.Part")
• Functions are stored as "<function>"
• Other non-primitive types are stored using their tostring() representation

Mixed tables (tables with both string and numeric keys) and pure arrays are accepted. Numeric keys are converted to string keys (e.g., index 1 becomes key "1"). If a numeric key collides with an existing string key, the explicit string key takes precedence.

local LogService = game:GetService("LogService")

-- Instance values are converted to their full path
LogService:Info("Touched {part}", {part = workspace.MyPart})
-- Context stores: {part = "Workspace.MyPart"}

-- Mixed tables are accepted; numeric keys become string keys
LogService:Info("Player {name}", {name = "Alice", 1, 2, 3})
-- Context stores: {name = "Alice", ["1"] = 1, ["2"] = 2, ["3"] = 3}

Warning

This service might have unexpected or unreliable behavior and content might be truncated. Don't rely on contents of events and messages emitted by this service for any important game logic.

Inherits from: Instance

Memory category: Instances

Tags: NotCreatable, Service

Methods

Inherited from Instance

Inherited from Object

LogService:ClearOutput

Clears Roblox Studio's Output window. The log history is also cleared, such that LogService:GetLogHistory() will not return any entries from before the ClearOutput() call.

Returns

LogService:Error

Logs a message at the MessageType.MessageError level and throws a structured error with optional context. As this method always throws, use LuaGlobals.pcall() to catch the error. The thrown error is a table with message, template, context, and stack fields, and a __tostring metamethod that returns the rendered message.

When a context table is provided, template placeholders like {key} in the message are replaced with the corresponding context values.

local LogService = game:GetService("LogService")

local ok, err = pcall(function()
	LogService:Error("Failed: {reason}", {reason = "timeout"})
end)
-- ok is false
-- err.message == "Failed: timeout"
-- err.context == {reason = "timeout"}
-- tostring(err) == "Failed: timeout"

Parameters

Returns

LogService:GetLogHistory

Returns a table of tables, each with the message string, message type, and timestamp of a message that the client displays in the Output window. Each inner table contains the following keys:

• message (string) -- the rendered message text.
• messageType (MessageType) -- the log level (MessageOutput, MessageInfo, MessageWarning, or MessageError).
• timestamp (number) -- the time the message was emitted, in seconds.
• context (dictionary) -- the structured key-value pairs if the message was emitted via a structured logging method; absent otherwise.

The history is capped at a maximum of 512 entries by default. Calling LogService:ClearOutput() empties the history, so subsequent calls return only entries logged after the clear.

Returns

LogService:Info

Logs a message at the MessageType.MessageInfo level. When a context table is provided, template placeholders like {key} in the message are replaced with the corresponding context values. The context is preserved as structured data for display in the Developer Console and Studio's Output window.

local LogService = game:GetService("LogService")

LogService:Info("User {name} has {count} items", {name = "Alice", count = 42})
-- Output: "User Alice has 42 items"

Parameters

Returns

LogService:Log

Logs a message at the specified MessageType level. This is a general-purpose method that combines the functionality of Output(), Info(), Warn(), and Error() into a single call with an explicit message type parameter.

When messageType is MessageType.MessageError, this method throws a structured error object (same behavior as Error()).

local LogService = game:GetService("LogService")

LogService:Log(Enum.MessageType.MessageInfo, "Event {action}", {action = "click"})

Parameters

Returns

LogService:Output

Logs a message at the MessageType.MessageOutput level. When a context table is provided, template placeholders like {key} in the message are replaced with the corresponding context values. The context is preserved as structured data for display in the Developer Console and Studio's Output window.

local LogService = game:GetService("LogService")

LogService:Output("Player {name} joined", {name = "Alice"})
-- Output: "Player Alice joined"

Parameters

Returns

LogService:Warn

Logs a message at the MessageType.MessageWarning level with optional structured context. When a context table is provided, template placeholders like {key} in the message are replaced with the corresponding context values. The context is preserved as structured data for display in the Developer Console and Studio's Output window.

local LogService = game:GetService("LogService")

LogService:Warn("Memory usage at {pct}%", {pct = 95})
-- Output: "Memory usage at 95%"

Parameters

Returns

Events

Inherited from Instance

Inherited from Object

LogService.MessageOut

Fires whenever a message is logged through the engine's output system, including calls to LuaGlobals.print(), RobloxGlobals.warn(), and the structured logging methods on LogService. The message parameter contains the fully rendered text (template placeholders already replaced). The context parameter carries the structured key-value pairs when the message was emitted via a method that accepts a context table; otherwise it is nil.

local LogService = game:GetService("LogService")

LogService.MessageOut:Connect(function(message, messageType, context)
	if messageType == Enum.MessageType.MessageError then
		print("Error:", message)
	end
	if context then
		-- Access structured data from structured logging calls
		for key, value in context do
			print(key, "=", value)
		end
	end
end)

Parameters

Code samples: View on Creator Hub (LogService-MessageOut1).

Properties

Inherited from Instance

Inherited from Object