# Built-in packages


Built-in packages allow users to toggle Unity features on or off through the Package Manager. Enabling or disabling a package reduces the run-time build size. For example, most Projects don’t use the legacy [Particle System](/engine/6000.3/manual/built-in-particle-system.md).

When you remove a built-in package of this feature, Unity does not include the related code and resources when you build your final application. Typically, these built-in packages contain only the [package manifest](/engine/6000.3/manual/packages-list/cus-pkg-lp/cus-pkg-development/cus-pkg-manifest/upm-manifest-pkg.md) and are bundled with Unity (rather than available on the package registry).

Use the following links to access the documentation for each package:

* Accessibility: [com.unity.modules.accessibility](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.AccessibilityModule.html)
* Adaptive Performance: [com.unity.modules.adaptiveperformance](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.AdaptivePerformanceModule.html)
* AI: [com.unity.modules.ai](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.AIModule.html)
* AMD: [com.unity.modules.amd](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.AMDModule.html)
* Android JNI: [com.unity.modules.androidjni](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.AndroidJNIModule.html)
* Animation: [com.unity.modules.animation](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.AnimationModule.html)
* Asset Bundle: [com.unity.modules.assetbundle](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.AssetBundleModule.html)
* Audio: [com.unity.modules.audio](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.AudioModule.html)
* Cloth: [com.unity.modules.cloth](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.ClothModule.html)
* Director: [com.unity.modules.director](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.DirectorModule.html)
* Image Conversion: [com.unity.modules.imageconversion](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.ImageConversionModule.html)
* IMGUI: [com.unity.modules.imgui](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.IMGUIModule.html)
* JSONSerialize: [com.unity.modules.jsonserialize](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.JSONSerializeModule.html)
* NVIDIA: [com.unity.modules.nvidia](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.NVIDIAModule.html)
* Particle System: [com.unity.modules.particlesystem](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.ParticleSystemModule.html)
* Physics: [com.unity.modules.physics](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.PhysicsModule.html)
* Physics 2D: [com.unity.modules.physics2d](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.Physics2DModule.html)
* Screen Capture: [com.unity.modules.screencapture](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.ScreenCaptureModule.html)
* Terrain: [com.unity.modules.terrain](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.TerrainModule.html)
* Terrain Physics: [com.unity.modules.terrainphysics](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.TerrainPhysicsModule.html)
* Tilemap: [com.unity.modules.tilemap](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.TilemapModule.html)
* UI: [com.unity.modules.ui](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.UIModule.html)
* UIElements: [com.unity.modules.uielements](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.UIElementsModule.html)
* Umbra: [com.unity.modules.umbra](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.UmbraModule.html)
* Unity Web Request: [com.unity.modules.unitywebrequest](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.UnityWebRequestModule.html)
* Unity Web Request Asset Bundle: [com.unity.modules.unitywebrequestassetbundle](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.UnityWebRequestAssetBundleModule.html)
* Unity Web Request Audio: [com.unity.modules.unitywebrequestaudio](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.UnityWebRequestAudioModule.html)
* Unity Web Request Texture: [com.unity.modules.unitywebrequesttexture](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.UnityWebRequestTextureModule.html)
* Unity Web Request WWW: [com.unity.modules.unitywebrequestwww](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.UnityWebRequestWWWModule.html)
* Vehicles: [com.unity.modules.vehicles](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.VehiclesModule.html)
* Video: [com.unity.modules.video](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.VideoModule.html)
* VR: [com.unity.modules.vr](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.VRModule.html)
* Wind: [com.unity.modules.wind](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.WindModule.html)
* XR: [com.unity.modules.xr](https://docs.unity3d.com/6000.3/Documentation/ScriptReference/UnityEngine.XRModule.html)