An object that allows events defined in one server-side Script to be subscribed to by another script for one-way communication.

BindableEvents do not allow for communication between the server and client. If you are looking for this functionality use RemoteEvent.

BindableEvents vs BindableFunctions

Unlike BindableEvents, BindableFunction|BindableFunctions allow for two-way communication between two scripts:

• When a script fires a BindableEvent it does not yield for a return. The script continues executing as the event is handled by the subscribed script asynchronously.
• When a script invokes a BindableFunction, however, that script yields until the event is handled and returned by the subscribed script synchronously. This allows for scripts to effectively pass data during and after an event.

BindableEvents vs RemoteEvents

While BindableEvents allow for one-way communication server-server scripts or client-client LocalScript|LocalScripts, RemoteEvent|RemoteEvents allow for one-way communicate the server and client. For more information on RemoteEvents, read the Articles/Remote Functions and Events|Remote Functions and Events article.

Parameter Limitations

Any type of Roblox object such as an Enumeration, Instance, or userdata can be passed as a parameter when a RemoteEvent is fired or a RemoteFunction invoked. Lua types such as numbers, strings, and booleans can also be passed, although there are some limitations on how data can be passed.

Mixed Tables

If a Table is passed as an argument to a BindableEvent it must be an array without missing entries or have string keys, not a mixture, or else the string keys will be lost.

Avoid passing a mixed table (some values indexed by number and others by key), as only the data indexed by number will be passed. For example, when the server receives the colorData table illustrated below, it only sees indices 1 and 2 containing "Blue" and "Yellow" while the other data is lost in the transfer. Note, however, that sub-tables do not need to be indexed in the same way as their parent — in other words, as long as each individual sub-table is indexed with the same type, all of the data is preserved.

Metatables are not preserved.

Non-String Indices

If any indices of a passed table are non-string type (Instance, userdata, function, another table, etc.), those indices will be converted to a string.

-- Mixed table
local colorData = {}
colorData[1] = "Blue"
colorData[2] = "Yellow"
colorData["Color1"] = "Green"
colorData["Color2"] = "Red"

-- Table with two key-indexed sub-tables
local playerData = {}
playerData["CharData"] = {
  -- All children indexed by key
  CharName = "Diva Dragonslayer",
  CharClass = "Knight"
}
playerData["Inventory"] = {
  -- All children numerically indexed
  "Sword",
  "Bow",
  "Rope"
}

Functions

Functions passed as parameters will not be replicated, therefore making it impossible to use these objects to pass functions between scripts.