Source: Roblox Creator Hub · CC BY 4.0 · View source · Code samples: MIT Imported 2026-10-03. Formatting adapted for this site.
HeapProfilerService
Inherits from: Instance → Object
HeapProfilerService captures snapshots of the Luau heap so that memory-profiling tools can analyze script memory usage. Requesting a profile runs a full garbage-collection cycle and then walks the heap of the target Luau virtual machine, producing a JSON report that breaks memory down by value type, memory category, and userdata class, together with an aggregated ownership graph and a list of unique and unparented instance references.
Profiles can be requested for either the server or a specific client. HeapProfilerService:ServerRequestDataAsync() returns the server's profile and HeapProfilerService:ClientRequestDataAsync() returns a given player's client profile. When the profiled machine differs from the caller, the data is generated remotely, compressed, and replicated back through the HeapProfilerService.OnNewData event before the yielding call resolves.
Inherits from: Instance
Memory category: Instances
Tags: NotCreatable, Service
Methods
| Name | Type / Returns | Description |
|---|---|---|
| HeapProfilerService:ClientRequestDataAsync | string | Yields until the Luau heap profile of the specified player's client is available, then returns it as a JSON string. |
| HeapProfilerService:ServerRequestDataAsync | string | Yields until the server's Luau heap profile is available, then returns it as a JSON string. |
Inherited from Instance
| Name | Type / Returns | Description |
|---|---|---|
| Instance:AddTag | () | Applies a tag to the instance. |
| Instance:children | Instances | Returns an array of the object's children. |
| Instance:ClearAllChildren | () | This method destroys all of an instance's children. |
| Instance:Clone | Instance | Create a copy of an instance and all its descendants, ignoring instances that are not Archivable. |
| Instance:clone | Instance | |
| Instance:Destroy | () | Sets the Instance.Parent property to nil, locks the Instance.Parent property, disconnects all connections, and calls Destroy() on all children. |
| Instance:destroy | () | |
| Instance:FindFirstAncestor | Instance? | Returns the first ancestor of the Instance whose Instance.Name is equal to the given name. |
| Instance:FindFirstAncestorOfClass | Instance? | Returns the first ancestor of the Instance whose Object.ClassName is equal to the given className. |
| Instance:FindFirstAncestorWhichIsA | Instance? | Returns the first ancestor of the Instance for whom Object:IsA() returns true for the given className. |
| Instance:FindFirstChild | Instance? | Returns the first child of the Instance found with the given name. |
| Instance:findFirstChild | Instance | |
| Instance:FindFirstChildOfClass | Instance? | Returns the first child of the Instance whose ClassName is equal to the given class name. |
| Instance:FindFirstChildWhichIsA | Instance? | Returns the first child of the Instance for whom Object:IsA() returns true for the given className. |
| Instance:FindFirstDescendant | Instance? | Returns the first descendant found with the given Instance.Name. |
| Instance:GetActor | Actor? | Returns the Actor associated with the Instance, if any. |
| Instance:GetAttribute | Variant | Returns the value which has been assigned to the given attribute name. |
| Instance:GetAttributeChangedSignal | RBXScriptSignal | Returns an event that fires when the given attribute changes. |
| Instance:GetAttributes | Dictionary | Returns a dictionary of the instance's attributes. |
| Instance:GetChildren | Instances | Returns an array containing all of the instance's children. |
| Instance:getChildren | Instances | |
| Instance:GetDebugId | string | Returns a coded string of the debug ID used internally by Roblox. |
| Instance:GetDescendants | Instances | Returns an array containing all of the descendants of the instance. |
| Instance:GetFullName | string | Returns a string describing the instance's ancestry. |
| Instance:GetStyled | Variant | Returns the styled or explicitly modified value of the specified property, or else the default property value if it hasn't been styled/modified. |
| Instance:GetStyledPropertyChangedSignal | RBXScriptSignal | Returns an event that fires when the given style property changes on the instance. |
| Instance:GetTags | Array | Gets an array of all tags applied to the instance. |
| Instance:HasTag | boolean | Check whether the instance has a given tag. |
| Instance:IsAncestorOf | boolean | Returns true if an Instance is an ancestor of the given descendant. |
| Instance:IsDescendantOf | boolean | Returns true if an Instance is a descendant of the given ancestor. |
| Instance:isDescendantOf | boolean | |
| Instance:IsPropertyModified | boolean | Returns true if the value stored in the specified property is not equal to the code-instantiated default. |
| Instance:QueryDescendants | Instances | Returns an array containing all descendants of the instance that match the selector string. |
| Instance:Remove | () | Sets the object's Parent to nil, and does the same for all its descendants. |
| Instance:remove | () | |
| Instance:RemoveTag | () | Removes a tag from the instance. |
| Instance:ResetPropertyToDefault | () | Resets a property to its default value. |
| Instance:SetAttribute | () | Sets the attribute with the given name to the given value. |
| Instance:WaitForChild | Instance | Returns the child of the Instance with the given name. If the child does not exist, it will yield the current thread until it does. |
Inherited from Object
| Name | Type / Returns | Description |
|---|---|---|
| Object:GetPropertyChangedSignal | RBXScriptSignal | Get an event that fires when a given property of the object changes. |
| Object:IsA | boolean | Returns true if an object's class matches or inherits from a given class. |
| Object:isA | boolean |
HeapProfilerService:ClientRequestDataAsync
Requests a Luau heap profile from the client belonging to player. When called on that client itself, the profile is generated locally and returned immediately. When called from the server, a request is sent to the client and this function yields until the compressed profile is replicated back through HeapProfilerService.OnNewData, decompressed, and returned. If the client does not respond within 10 seconds, the request fails.
The returned string is JSON containing a Report section (heap memory broken down by value type, memory category, and userdata class, plus an aggregated size graph) and a Refs section (unique and unparented instance references).
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| player | Player | The Player whose client Luau heap should be profiled. |
Returns
| Type | Description |
|---|---|
| string | A JSON-encoded string containing the client's Luau heap profile. |
| Field | Value |
|---|---|
| tags | ["Yields"] |
| security | PluginSecurity |
| thread safety | Unsafe |
HeapProfilerService:ServerRequestDataAsync
Requests a Luau heap profile from the server. When called on the server, the profile is generated locally and returned immediately. When called from a client, a request is sent to the server and this function yields until the compressed profile is replicated back through HeapProfilerService.OnNewData, decompressed, and returned. If the server does not respond within 10 seconds, the request fails.
The returned string has the same JSON structure as HeapProfilerService:ClientRequestDataAsync().
Returns
| Type | Description |
|---|---|
| string | A JSON-encoded string containing the server's Luau heap profile. |
| Field | Value |
|---|---|
| tags | ["Yields"] |
| security | PluginSecurity |
| thread safety | Unsafe |
Events
| Name | Type / Returns | Description |
|---|---|---|
| HeapProfilerService.OnNewData | Fires on the requesting machine with the compressed Luau heap profile produced for an earlier request. |
Inherited from Instance
| Name | Type / Returns | Description |
|---|---|---|
| Instance.AncestryChanged | Fires when the Instance.Parent property of this object or one of its ancestors is changed. | |
| Instance.AttributeChanged | Fires whenever an attribute is changed on the Instance. | |
| Instance.ChildAdded | Fires after an object is parented to this Instance. | |
| Instance.childAdded | ||
| Instance.ChildRemoved | Fires after a child is removed from this Instance. | |
| Instance.DescendantAdded | Fires after a descendant is added to the Instance. | |
| Instance.DescendantRemoving | Fires immediately before a descendant of the Instance is removed. | |
| Instance.Destroying | Fires immediately before (or is deferred until after) the instance is destroyed via Instance:Destroy(). | |
| Instance.StyledPropertiesChanged | Fires whenever any style property is changed on the instance, including when a property is set to nil. |
Inherited from Object
| Name | Type / Returns | Description |
|---|---|---|
| Object.Changed | Fires immediately after a property of the object changes, with some limitations. |
HeapProfilerService.OnNewData
Delivers a Luau heap profile that was generated on a remote machine in response to a HeapProfilerService:ClientRequestDataAsync() or HeapProfilerService:ServerRequestDataAsync() call. The profile JSON is zstd-compressed and carried in jsonString; the receiving service decompresses it, matches it to the pending request by id, and resolves the yielding call. The compressedLength and uncompressedLength arguments report the buffer's size before and after decompression.
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| player | Player | The Player the profile is being delivered to, or nil when the data is replicated to the server. | |
| jsonString | buffer | A buffer holding the zstd-compressed JSON heap profile. | |
| id | int | The identifier of the request this data corresponds to. | |
| compressedLength | int | The size, in bytes, of the compressed profile buffer. | |
| uncompressedLength | int | The size, in bytes, of the heap profile JSON after decompression. |
| Field | Value |
|---|---|
| security | PluginSecurity |
Properties
Inherited from Instance
| Name | Type / Returns | Description |
|---|---|---|
| Instance.Archivable | boolean | Determines if an Instance and its descendants can be cloned using Instance:Clone(), and can be saved/published. |
| Instance.archivable | boolean | |
| Instance.Capabilities | SecurityCapabilities | The set of capabilities allowed to be used for scripts inside this container. |
| Instance.IsInSandbox | boolean | Indicates whether the instance is inside a sandboxed container. |
| Instance.Name | string | A non-unique identifier of the Instance. |
| Instance.Parent | Instance | Determines the hierarchical parent of the Instance. |
| Instance.PredictionMode | PredictionMode | Reflects the client-side prediction mode applied to the instance under server-authoritative physics. |
| Instance.RobloxLocked | boolean | A deprecated property that used to protect CoreGui objects. |
| Instance.Sandboxed | boolean | When enabled, the instance can only access abilities in its Capabilities list. |
| Instance.UniqueId | UniqueId | A unique identifier for the instance. |
Inherited from Object
| Name | Type / Returns | Description |
|---|---|---|
| Object.ClassName | string | A read-only string representing the class this Object belongs to. |
| Object.className | string |