diff --git a/packages/builder/src/pages/builder/app/[application]/design/[screenId]/[componentId]/new/_components/NewComponentPanel.svelte b/packages/builder/src/pages/builder/app/[application]/design/[screenId]/[componentId]/new/_components/NewComponentPanel.svelte
index aa0b26f6b7..784642787b 100644
--- a/packages/builder/src/pages/builder/app/[application]/design/[screenId]/[componentId]/new/_components/NewComponentPanel.svelte
+++ b/packages/builder/src/pages/builder/app/[application]/design/[screenId]/[componentId]/new/_components/NewComponentPanel.svelte
@@ -13,6 +13,11 @@
   import { fly } from "svelte/transition"
   import { findComponentPath } from "@/helpers/components"
 
+  // Smallest possible 1x1 transparent GIF
+  const ghost = new Image(1, 1)
+  ghost.src =
+    "data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw=="
+
   let searchString
   let searchRef
   let selectedIndex
@@ -217,7 +222,8 @@
     }
   })
 
-  const onDragStart = component => {
+  const onDragStart = (e, component) => {
+    e.dataTransfer.setDragImage(ghost, 0, 0)
     previewStore.startDrag(component)
   }
 
@@ -250,7 +256,7 @@
             {#each category.children as component}
               <div
                 draggable="true"
-                on:dragstart={() => onDragStart(component.component)}
+                on:dragstart={e => onDragStart(e, component.component)}
                 on:dragend={onDragEnd}
                 class="component"
                 class:selected={selectedIndex === orderMap[component.component]}
@@ -308,7 +314,7 @@
   }
   .component:hover {
     background: var(--spectrum-global-color-gray-300);
-    cursor: pointer;
+    cursor: grab;
   }
   .component :global(.spectrum-Body) {
     line-height: 1.2 !important;
diff --git a/packages/builder/src/stores/builder/app.ts b/packages/builder/src/stores/builder/app.ts
index 3c8ed4afc1..abebb5d9f1 100644
--- a/packages/builder/src/stores/builder/app.ts
+++ b/packages/builder/src/stores/builder/app.ts
@@ -39,7 +39,7 @@ interface AppMetaState {
   appInstance: { _id: string } | null
   initialised: boolean
   hasAppPackage: boolean
-  usedPlugins: Plugin[] | null
+  usedPlugins: Plugin[]
   automations: AutomationSettings
   routes: { [key: string]: any }
   version?: string
@@ -76,7 +76,7 @@ export const INITIAL_APP_META_STATE: AppMetaState = {
   appInstance: null,
   initialised: false,
   hasAppPackage: false,
-  usedPlugins: null,
+  usedPlugins: [],
   automations: {},
   routes: {},
 }
@@ -109,7 +109,7 @@ export class AppMetaStore extends BudiStore<AppMetaState> {
       appInstance: app.instance,
       revertableVersion: app.revertableVersion,
       upgradableVersion: app.upgradableVersion,
-      usedPlugins: app.usedPlugins || null,
+      usedPlugins: app.usedPlugins || [],
       icon: app.icon,
       features: {
         ...INITIAL_APP_META_STATE.features,
diff --git a/packages/builder/src/stores/builder/components.ts b/packages/builder/src/stores/builder/components.ts
index a8f52e2660..ad221cc67d 100644
--- a/packages/builder/src/stores/builder/components.ts
+++ b/packages/builder/src/stores/builder/components.ts
@@ -139,10 +139,6 @@ export class ComponentStore extends BudiStore<ComponentState> {
 
   /**
    * Retrieve the component definition object
-   * @param {string} componentType
-   * @example
-   * '@budibase/standard-components/container'
-   * @returns {object}
    */
   getDefinition(componentType: string) {
     if (!componentType) {
@@ -151,10 +147,6 @@ export class ComponentStore extends BudiStore<ComponentState> {
     return get(this.store).components[componentType]
   }
 
-  /**
-   *
-   * @returns {object}
-   */
   getDefaultDatasource() {
     // Ignore users table
     const validTables = get(tables).list.filter(x => x._id !== "ta_users")
@@ -188,8 +180,6 @@ export class ComponentStore extends BudiStore<ComponentState> {
   /**
    * Takes an enriched component instance and applies any required migration
    * logic
-   * @param {object} enrichedComponent
-   * @returns {object} migrated Component
    */
   migrateSettings(enrichedComponent: Component) {
     const componentPrefix = "@budibase/standard-components"
@@ -230,22 +220,15 @@ export class ComponentStore extends BudiStore<ComponentState> {
     for (let setting of filterableTypes || []) {
       const isLegacy = Array.isArray(enrichedComponent[setting.key])
       if (isLegacy) {
-        const processedSetting = utils.processSearchFilters(
+        enrichedComponent[setting.key] = utils.processSearchFilters(
           enrichedComponent[setting.key]
         )
-        enrichedComponent[setting.key] = processedSetting
         migrated = true
       }
     }
     return migrated
   }
 
-  /**
-   *
-   * @param {object} component
-   * @param {object} opts
-   * @returns
-   */
   enrichEmptySettings(
     component: Component,
     opts: { screen?: Screen; parent?: Component; useDefaultValues?: boolean }
@@ -427,17 +410,10 @@ export class ComponentStore extends BudiStore<ComponentState> {
     }
   }
 
-  /**
-   *
-   * @param {string} componentName
-   * @param {object} presetProps
-   * @param {object} parent
-   * @returns
-   */
   createInstance(
     componentType: string,
-    presetProps: any,
-    parent: any
+    presetProps?: Record<string, any>,
+    parent?: Component
   ): Component | null {
     const screen = get(selectedScreen)
     if (!screen) {
@@ -463,7 +439,7 @@ export class ComponentStore extends BudiStore<ComponentState> {
       _id: Helpers.uuid(),
       _component: definition.component,
       _styles: {
-        normal: {},
+        normal: { ...presetProps?._styles?.normal },
         hover: {},
         active: {},
       },
@@ -512,19 +488,11 @@ export class ComponentStore extends BudiStore<ComponentState> {
     }
   }
 
-  /**
-   *
-   * @param {string} componentName
-   * @param {object} presetProps
-   * @param {object} parent
-   * @param {number} index
-   * @returns
-   */
   async create(
     componentType: string,
-    presetProps: any,
-    parent: Component,
-    index: number
+    presetProps?: Record<string, any>,
+    parent?: Component,
+    index?: number
   ) {
     const state = get(this.store)
     const componentInstance = this.createInstance(
@@ -611,13 +579,6 @@ export class ComponentStore extends BudiStore<ComponentState> {
     return componentInstance
   }
 
-  /**
-   *
-   * @param {function} patchFn
-   * @param {string} componentId
-   * @param {string} screenId
-   * @returns
-   */
   async patch(
     patchFn: (component: Component, screen: Screen) => any,
     componentId?: string,
@@ -652,11 +613,6 @@ export class ComponentStore extends BudiStore<ComponentState> {
     await screenStore.patch(patchScreen, screenId)
   }
 
-  /**
-   *
-   * @param {object} component
-   * @returns
-   */
   async delete(component: Component) {
     if (!component) {
       return
@@ -737,13 +693,6 @@ export class ComponentStore extends BudiStore<ComponentState> {
     })
   }
 
-  /**
-   *
-   * @param {object} targetComponent
-   * @param {string} mode
-   * @param {object} targetScreen
-   * @returns
-   */
   async paste(
     targetComponent: Component,
     mode: string,
@@ -1101,6 +1050,7 @@ export class ComponentStore extends BudiStore<ComponentState> {
 
   async updateStyles(styles: Record<string, string>, id: string) {
     const patchFn = (component: Component) => {
+      delete component._placeholder
       component._styles.normal = {
         ...component._styles.normal,
         ...styles,
@@ -1231,7 +1181,7 @@ export class ComponentStore extends BudiStore<ComponentState> {
     }
 
     // Create new parent instance
-    const newParentDefinition = this.createInstance(parentType, null, parent)
+    const newParentDefinition = this.createInstance(parentType)
     if (!newParentDefinition) {
       return
     }
@@ -1267,10 +1217,6 @@ export class ComponentStore extends BudiStore<ComponentState> {
 
   /**
    * Check if the components settings have been cached
-   * @param {string} componentType
-   * @example
-   * '@budibase/standard-components/container'
-   * @returns {boolean}
    */
   isCached(componentType: string) {
     const settings = get(this.store).settingsCache
@@ -1279,11 +1225,6 @@ export class ComponentStore extends BudiStore<ComponentState> {
 
   /**
    * Cache component settings
-   * @param {string} componentType
-   * @param {object} definition
-   * @example
-   * '@budibase/standard-components/container'
-   * @returns {array} the settings
    */
   cacheSettings(componentType: string, definition: ComponentDefinition | null) {
     let settings: ComponentSetting[] = []
@@ -1313,12 +1254,7 @@ export class ComponentStore extends BudiStore<ComponentState> {
   /**
    * Retrieve an array of the component settings.
    * These settings are cached because they cannot change at run time.
-   *
    * Searches a component's definition for a setting matching a certain predicate.
-   * @param {string} componentType
-   * @example
-   * '@budibase/standard-components/container'
-   * @returns {Array<object>}
    */
   getComponentSettings(componentType: string) {
     if (!componentType) {
diff --git a/packages/builder/src/stores/builder/navigation.ts b/packages/builder/src/stores/builder/navigation.ts
index 1574efee2a..1ef019a11c 100644
--- a/packages/builder/src/stores/builder/navigation.ts
+++ b/packages/builder/src/stores/builder/navigation.ts
@@ -4,15 +4,13 @@ import { appStore } from "@/stores/builder"
 import { BudiStore } from "../BudiStore"
 import { AppNavigation, AppNavigationLink, UIObject } from "@budibase/types"
 
-interface BuilderNavigationStore extends AppNavigation {}
-
 export const INITIAL_NAVIGATION_STATE = {
   navigation: "Top",
   links: [],
   textAlign: "Left",
 }
 
-export class NavigationStore extends BudiStore<BuilderNavigationStore> {
+export class NavigationStore extends BudiStore<AppNavigation> {
   constructor() {
     super(INITIAL_NAVIGATION_STATE)
   }
diff --git a/packages/builder/src/stores/builder/preview.ts b/packages/builder/src/stores/builder/preview.ts
index 87b2b9355e..9aeaf99346 100644
--- a/packages/builder/src/stores/builder/preview.ts
+++ b/packages/builder/src/stores/builder/preview.ts
@@ -1,5 +1,7 @@
 import { get } from "svelte/store"
 import { BudiStore } from "../BudiStore"
+import { componentStore } from "./components"
+import { selectedScreen } from "./screens"
 
 type PreviewDevice = "desktop" | "tablet" | "mobile"
 type PreviewEventHandler = (name: string, payload?: any) => void
@@ -54,10 +56,21 @@ export class PreviewStore extends BudiStore<PreviewState> {
     }))
   }
 
-  startDrag(component: any) {
+  async startDrag(componentType: string) {
+    let componentId
+    const gridScreen = get(selectedScreen)?.props?.layout === "grid"
+    if (gridScreen) {
+      const component = await componentStore.create(componentType, {
+        _placeholder: true,
+        _styles: { normal: { opacity: 0 } },
+      })
+      componentId = component?._id
+    }
     this.sendEvent("dragging-new-component", {
       dragging: true,
-      component,
+      componentType,
+      componentId,
+      gridScreen,
     })
   }
 
diff --git a/packages/client/package.json b/packages/client/package.json
index 2ae049f6d0..72be403698 100644
--- a/packages/client/package.json
+++ b/packages/client/package.json
@@ -5,7 +5,7 @@
   "module": "dist/budibase-client.js",
   "main": "dist/budibase-client.js",
   "type": "module",
-  "svelte": "src/index.js",
+  "svelte": "src/index.ts",
   "exports": {
     ".": {
       "import": "./dist/budibase-client.js",
diff --git a/packages/client/src/components/ClientApp.svelte b/packages/client/src/components/ClientApp.svelte
index 2840d82f47..7144105fd8 100644
--- a/packages/client/src/components/ClientApp.svelte
+++ b/packages/client/src/components/ClientApp.svelte
@@ -44,6 +44,7 @@
   import MaintenanceScreen from "components/MaintenanceScreen.svelte"
   import SnippetsProvider from "./context/SnippetsProvider.svelte"
   import EmbedProvider from "./context/EmbedProvider.svelte"
+  import GridNewComponentDNDHandler from "components/preview/GridNewComponentDNDHandler.svelte"
 
   // Provide contexts
   setContext("sdk", SDK)
@@ -266,6 +267,7 @@
                       {#if $builderStore.inBuilder}
                         <DNDHandler />
                         <GridDNDHandler />
+                        <GridNewComponentDNDHandler />
                       {/if}
                     </div>
                   </SnippetsProvider>
diff --git a/packages/client/src/components/preview/GridNewComponentDNDHandler.svelte b/packages/client/src/components/preview/GridNewComponentDNDHandler.svelte
new file mode 100644
index 0000000000..8a3da6f419
--- /dev/null
+++ b/packages/client/src/components/preview/GridNewComponentDNDHandler.svelte
@@ -0,0 +1,166 @@
+<script>
+  import { onDestroy, getContext } from "svelte"
+  import { builderStore, componentStore, screenStore } from "stores"
+  import { Utils, memo } from "@budibase/frontend-core"
+  import { GridRowHeight } from "constants"
+  import { GridParams, getGridVar, Devices } from "utils/grid"
+
+  const context = getContext("context")
+
+  // Smallest possible 1x1 transparent GIF
+  const ghost = new Image(1, 1)
+  ghost.src =
+    "data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw=="
+
+  let dragInfo
+  let styles = memo()
+
+  $: placeholderID = findPlaceholderID($screenStore.activeScreen)
+  $: handleNewPlaceholderID(placeholderID)
+
+  // Grid CSS variables
+  $: device = $context.device.mobile ? Devices.Mobile : Devices.Desktop
+  $: vars = {
+    colStart: getGridVar(device, GridParams.ColStart),
+    colEnd: getGridVar(device, GridParams.ColEnd),
+    rowStart: getGridVar(device, GridParams.RowStart),
+    rowEnd: getGridVar(device, GridParams.RowEnd),
+  }
+
+  // Some memoisation of primitive types for performance
+  $: id = dragInfo?.id
+
+  // Set ephemeral styles
+  $: instance = componentStore.actions.getComponentInstance(id)
+  $: $instance?.setEphemeralStyles($styles)
+
+  const findPlaceholderID = screen => {
+    return screen?.props?._children?.find(c => c._placeholder)?._id
+  }
+
+  const sleep = ms => new Promise(resolve => setTimeout(resolve, ms))
+
+  const handleNewPlaceholderID = async placeholderID => {
+    if (!placeholderID) {
+      stopDragging()
+      return
+    }
+    await sleep(100)
+    onDragStart(placeholderID)
+  }
+
+  // Sugar for a combination of both min and max
+  const minMax = (value, min, max) => Math.min(max, Math.max(min, value))
+
+  const processEvent = Utils.domDebounce((mouseX, mouseY) => {
+    if (!dragInfo?.grid) {
+      return
+    }
+    const { grid, domGrid } = dragInfo
+    const { startX, startY, rowStart, rowEnd, colStart, colEnd } = grid
+    if (!domGrid) {
+      return
+    }
+    const cols = parseInt(domGrid.dataset.cols)
+    const colSize = parseInt(domGrid.dataset.colSize)
+    const diffX = mouseX - startX
+    let deltaX = Math.round(diffX / colSize)
+    const diffY = mouseY - startY
+    let deltaY = Math.round(diffY / GridRowHeight)
+    deltaX = minMax(deltaX, 1 - colStart, cols + 1 - colEnd)
+    deltaY = Math.max(deltaY, 1 - rowStart)
+    const newStyles = {
+      [vars.colStart]: colStart + deltaX,
+      [vars.colEnd]: colEnd + deltaX,
+      [vars.rowStart]: rowStart + deltaY,
+      [vars.rowEnd]: rowEnd + deltaY,
+      opacity: 1,
+    }
+    styles.set(newStyles)
+  })
+
+  const handleEvent = e => {
+    e.preventDefault()
+    e.stopPropagation()
+    processEvent(e.clientX, e.clientY)
+  }
+
+  // Callback when initially starting a drag on a draggable component
+  const onDragStart = id => {
+    console.log("DRAG START", id)
+    // Find grid parent and read from DOM
+    const domComponent = document.getElementsByClassName(id)[0]
+    const domGrid = domComponent?.closest(".grid")
+    if (!domGrid) {
+      return
+    }
+    const styles = getComputedStyle(domComponent)
+    const bounds = domComponent.getBoundingClientRect()
+
+    // Show as active
+    domComponent.classList.add("dragging")
+    domGrid.classList.add("highlight")
+    builderStore.actions.selectComponent(id)
+
+    // Update state
+    dragInfo = {
+      domComponent,
+      domGrid,
+      id,
+      gridId: domGrid.parentNode.dataset.id,
+      grid: {
+        startX: bounds.left + bounds.width / 2,
+        startY: bounds.top + bounds.height / 2,
+        rowStart: parseInt(styles["grid-row-start"]),
+        rowEnd: parseInt(styles["grid-row-end"]),
+        colStart: parseInt(styles["grid-column-start"]),
+        colEnd: parseInt(styles["grid-column-end"]),
+      },
+    }
+
+    // Add event handler to clear all drag state when dragging ends
+    document.addEventListener("dragover", onDrag, false)
+
+    // Add event handler to clear all drag state when dragging ends
+    document.addEventListener("dragEnd", stopDragging, false)
+    document.addEventListener("drop", stopDragging, false)
+  }
+
+  const onDrag = e => {
+    if (!dragInfo) {
+      return
+    }
+    handleEvent(e)
+  }
+
+  // Callback when drag stops (whether dropped or not)
+  const stopDragging = async () => {
+    if (!dragInfo) {
+      return
+    }
+    console.log("END")
+    const { id, domGrid, domComponent } = dragInfo
+
+    // Reset DOM
+    domComponent.classList.remove("dragging")
+    domGrid.classList.remove("highlight")
+    document.removeEventListener("dragover", onDrag, false)
+    document.removeEventListener("dragend", stopDragging, false)
+    document.removeEventListener("drop", stopDragging, false)
+
+    // Save changes
+    if ($styles) {
+      builderStore.actions.updateStyles($styles, id)
+    }
+
+    // Reset state
+    dragInfo = null
+    styles.set(null)
+  }
+
+  onDestroy(() => {
+    document.removeEventListener("dragover", onDrag, false)
+    document.removeEventListener("dragend", stopDragging, false)
+    document.removeEventListener("drop", stopDragging, false)
+  })
+</script>
diff --git a/packages/client/src/index.d.ts b/packages/client/src/index.d.ts
deleted file mode 100644
index 7e13670b33..0000000000
--- a/packages/client/src/index.d.ts
+++ /dev/null
@@ -1,5 +0,0 @@
-interface Window {
-  "##BUDIBASE_APP_ID##": string
-  "##BUDIBASE_IN_BUILDER##": string
-  MIGRATING_APP: boolean
-}
diff --git a/packages/client/src/index.js b/packages/client/src/index.js
deleted file mode 100644
index 8a48aa08e5..0000000000
--- a/packages/client/src/index.js
+++ /dev/null
@@ -1,138 +0,0 @@
-import ClientApp from "./components/ClientApp.svelte"
-import UpdatingApp from "./components/UpdatingApp.svelte"
-import {
-  builderStore,
-  appStore,
-  blockStore,
-  componentStore,
-  environmentStore,
-  dndStore,
-  eventStore,
-  hoverStore,
-  stateStore,
-} from "./stores"
-import loadSpectrumIcons from "@budibase/bbui/spectrum-icons-vite.js"
-import { get } from "svelte/store"
-import { initWebsocket } from "./websocket.js"
-
-// Provide svelte and svelte/internal as globals for custom components
-import * as svelte from "svelte"
-import * as internal from "svelte/internal"
-
-window.svelte_internal = internal
-window.svelte = svelte
-
-// Initialise spectrum icons
-loadSpectrumIcons()
-
-let app
-
-const loadBudibase = async () => {
-  // Update builder store with any builder flags
-  builderStore.set({
-    ...get(builderStore),
-    inBuilder: !!window["##BUDIBASE_IN_BUILDER##"],
-    layout: window["##BUDIBASE_PREVIEW_LAYOUT##"],
-    screen: window["##BUDIBASE_PREVIEW_SCREEN##"],
-    selectedComponentId: window["##BUDIBASE_SELECTED_COMPONENT_ID##"],
-    previewId: window["##BUDIBASE_PREVIEW_ID##"],
-    theme: window["##BUDIBASE_PREVIEW_THEME##"],
-    customTheme: window["##BUDIBASE_PREVIEW_CUSTOM_THEME##"],
-    previewDevice: window["##BUDIBASE_PREVIEW_DEVICE##"],
-    navigation: window["##BUDIBASE_PREVIEW_NAVIGATION##"],
-    hiddenComponentIds: window["##BUDIBASE_HIDDEN_COMPONENT_IDS##"],
-    usedPlugins: window["##BUDIBASE_USED_PLUGINS##"],
-    location: window["##BUDIBASE_LOCATION##"],
-    snippets: window["##BUDIBASE_SNIPPETS##"],
-    componentErrors: window["##BUDIBASE_COMPONENT_ERRORS##"],
-  })
-
-  // Set app ID - this window flag is set by both the preview and the real
-  // server rendered app HTML
-  appStore.actions.setAppId(window["##BUDIBASE_APP_ID##"])
-
-  // Set the flag used to determine if the app is being loaded via an iframe
-  appStore.actions.setAppEmbedded(
-    window["##BUDIBASE_APP_EMBEDDED##"] === "true"
-  )
-
-  if (window.MIGRATING_APP) {
-    new UpdatingApp({
-      target: window.document.body,
-    })
-    return
-  }
-
-  // Fetch environment info
-  if (!get(environmentStore)?.loaded) {
-    await environmentStore.actions.fetchEnvironment()
-  }
-
-  // Register handler for runtime events from the builder
-  window.handleBuilderRuntimeEvent = (type, data) => {
-    if (!window["##BUDIBASE_IN_BUILDER##"]) {
-      return
-    }
-    if (type === "event-completed") {
-      eventStore.actions.resolveEvent(data)
-    } else if (type === "eject-block") {
-      const block = blockStore.actions.getBlock(data)
-      block?.eject()
-    } else if (type === "dragging-new-component") {
-      const { dragging, component } = data
-      if (dragging) {
-        const definition =
-          componentStore.actions.getComponentDefinition(component)
-        dndStore.actions.startDraggingNewComponent({ component, definition })
-      } else {
-        dndStore.actions.reset()
-      }
-    } else if (type === "request-context") {
-      const { selectedComponentInstance, screenslotInstance } =
-        get(componentStore)
-      const instance = selectedComponentInstance || screenslotInstance
-      const context = instance?.getDataContext()
-      let stringifiedContext = null
-      try {
-        stringifiedContext = JSON.stringify(context)
-      } catch (error) {
-        // Ignore - invalid context
-      }
-      eventStore.actions.dispatchEvent("provide-context", {
-        context: stringifiedContext,
-      })
-    } else if (type === "hover-component") {
-      hoverStore.actions.hoverComponent(data, false)
-    } else if (type === "builder-meta") {
-      builderStore.actions.setMetadata(data)
-    } else if (type === "builder-state") {
-      const [[key, value]] = Object.entries(data)
-      stateStore.actions.setValue(key, value)
-    }
-  }
-
-  // Register any custom components
-  if (window["##BUDIBASE_CUSTOM_COMPONENTS##"]) {
-    window["##BUDIBASE_CUSTOM_COMPONENTS##"].forEach(component => {
-      componentStore.actions.registerCustomComponent(component)
-    })
-  }
-
-  // Make a callback available for custom component bundles to register
-  // themselves at runtime
-  window.registerCustomComponent =
-    componentStore.actions.registerCustomComponent
-
-  // Initialise websocket
-  initWebsocket()
-
-  // Create app if one hasn't been created yet
-  if (!app) {
-    app = new ClientApp({
-      target: window.document.body,
-    })
-  }
-}
-
-// Attach to window so the HTML template can call this when it loads
-window.loadBudibase = loadBudibase
diff --git a/packages/client/src/index.ts b/packages/client/src/index.ts
index 08330a60fa..e7d454e2f1 100644
--- a/packages/client/src/index.ts
+++ b/packages/client/src/index.ts
@@ -1,6 +1,83 @@
+import ClientApp from "./components/ClientApp.svelte"
+import UpdatingApp from "./components/UpdatingApp.svelte"
+import {
+  builderStore,
+  appStore,
+  blockStore,
+  componentStore,
+  environmentStore,
+  dndStore,
+  eventStore,
+  hoverStore,
+  stateStore,
+} from "@/stores"
+import { get } from "svelte/store"
+import { initWebsocket } from "@/websocket"
 import { APIClient } from "@budibase/frontend-core"
-import type { ActionTypes } from "./constants"
+import type { ActionTypes } from "@/constants"
 import { Readable } from "svelte/store"
+import {
+  Screen,
+  Layout,
+  Theme,
+  AppCustomTheme,
+  PreviewDevice,
+  AppNavigation,
+  Plugin,
+  Snippet,
+  UIComponentError,
+  CustomComponent,
+} from "@budibase/types"
+
+// Provide svelte and svelte/internal as globals for custom components
+import * as svelte from "svelte"
+// @ts-ignore
+import * as internal from "svelte/internal"
+window.svelte_internal = internal
+window.svelte = svelte
+
+// Initialise spectrum icons
+// eslint-disable-next-line local-rules/no-budibase-imports
+import loadSpectrumIcons from "@budibase/bbui/spectrum-icons-vite.js"
+loadSpectrumIcons()
+
+// Extend global window scope
+declare global {
+  interface Window {
+    // Data from builder
+    "##BUDIBASE_APP_ID##"?: string
+    "##BUDIBASE_IN_BUILDER##"?: true
+    "##BUDIBASE_PREVIEW_LAYOUT##"?: Layout
+    "##BUDIBASE_PREVIEW_SCREEN##"?: Screen
+    "##BUDIBASE_SELECTED_COMPONENT_ID##"?: string
+    "##BUDIBASE_PREVIEW_ID##"?: number
+    "##BUDIBASE_PREVIEW_THEME##"?: Theme
+    "##BUDIBASE_PREVIEW_CUSTOM_THEME##"?: AppCustomTheme
+    "##BUDIBASE_PREVIEW_DEVICE##"?: PreviewDevice
+    "##BUDIBASE_APP_EMBEDDED##"?: string // This is a bool wrapped in a string
+    "##BUDIBASE_PREVIEW_NAVIGATION##"?: AppNavigation
+    "##BUDIBASE_HIDDEN_COMPONENT_IDS##"?: string[]
+    "##BUDIBASE_USED_PLUGINS##"?: Plugin[]
+    "##BUDIBASE_LOCATION##"?: {
+      protocol: string
+      hostname: string
+      port: string
+    }
+    "##BUDIBASE_SNIPPETS##"?: Snippet[]
+    "##BUDIBASE_COMPONENT_ERRORS##"?: Record<string, UIComponentError>[]
+    "##BUDIBASE_CUSTOM_COMPONENTS##"?: CustomComponent[]
+
+    // Other flags
+    MIGRATING_APP: boolean
+
+    // Client additions
+    handleBuilderRuntimeEvent: (type: string, data: any) => void
+    registerCustomComponent: typeof componentStore.actions.registerCustomComponent
+    loadBudibase: typeof loadBudibase
+    svelte: typeof svelte
+    svelte_internal: typeof internal
+  }
+}
 
 export interface SDK {
   API: APIClient
@@ -29,3 +106,119 @@ export type Component = Readable<{
 }>
 
 export type Context = Readable<{}>
+
+let app: ClientApp
+
+const loadBudibase = async () => {
+  // Update builder store with any builder flags
+  builderStore.set({
+    ...get(builderStore),
+    inBuilder: !!window["##BUDIBASE_IN_BUILDER##"],
+    layout: window["##BUDIBASE_PREVIEW_LAYOUT##"],
+    screen: window["##BUDIBASE_PREVIEW_SCREEN##"],
+    selectedComponentId: window["##BUDIBASE_SELECTED_COMPONENT_ID##"],
+    previewId: window["##BUDIBASE_PREVIEW_ID##"],
+    theme: window["##BUDIBASE_PREVIEW_THEME##"],
+    customTheme: window["##BUDIBASE_PREVIEW_CUSTOM_THEME##"],
+    previewDevice: window["##BUDIBASE_PREVIEW_DEVICE##"],
+    navigation: window["##BUDIBASE_PREVIEW_NAVIGATION##"],
+    hiddenComponentIds: window["##BUDIBASE_HIDDEN_COMPONENT_IDS##"],
+    usedPlugins: window["##BUDIBASE_USED_PLUGINS##"],
+    location: window["##BUDIBASE_LOCATION##"],
+    snippets: window["##BUDIBASE_SNIPPETS##"],
+    componentErrors: window["##BUDIBASE_COMPONENT_ERRORS##"],
+  })
+
+  // Set app ID - this window flag is set by both the preview and the real
+  // server rendered app HTML
+  appStore.actions.setAppId(window["##BUDIBASE_APP_ID##"])
+
+  // Set the flag used to determine if the app is being loaded via an iframe
+  appStore.actions.setAppEmbedded(
+    window["##BUDIBASE_APP_EMBEDDED##"] === "true"
+  )
+
+  if (window.MIGRATING_APP) {
+    new UpdatingApp({
+      target: window.document.body,
+    })
+    return
+  }
+
+  // Fetch environment info
+  if (!get(environmentStore)?.loaded) {
+    await environmentStore.actions.fetchEnvironment()
+  }
+
+  // Register handler for runtime events from the builder
+  window.handleBuilderRuntimeEvent = (type, data) => {
+    if (!window["##BUDIBASE_IN_BUILDER##"]) {
+      return
+    }
+    if (type === "event-completed") {
+      eventStore.actions.resolveEvent(data)
+    } else if (type === "eject-block") {
+      const block = blockStore.actions.getBlock(data)
+      block?.eject()
+    } else if (type === "dragging-new-component") {
+      const { dragging, component, componentId } = data
+      if (dragging) {
+        const definition =
+          componentStore.actions.getComponentDefinition(component)
+        dndStore.actions.startDraggingNewComponent({
+          component,
+          definition,
+          componentId,
+        })
+      } else {
+        dndStore.actions.reset()
+      }
+    } else if (type === "request-context") {
+      const { selectedComponentInstance, screenslotInstance } =
+        get(componentStore)
+      const instance = selectedComponentInstance || screenslotInstance
+      const context = instance?.getDataContext()
+      let stringifiedContext = null
+      try {
+        stringifiedContext = JSON.stringify(context)
+      } catch (error) {
+        // Ignore - invalid context
+      }
+      eventStore.actions.dispatchEvent("provide-context", {
+        context: stringifiedContext,
+      })
+    } else if (type === "hover-component") {
+      hoverStore.actions.hoverComponent(data, false)
+    } else if (type === "builder-meta") {
+      builderStore.actions.setMetadata(data)
+    } else if (type === "builder-state") {
+      const [[key, value]] = Object.entries(data)
+      stateStore.actions.setValue(key, value)
+    }
+  }
+
+  // Register any custom components
+  if (window["##BUDIBASE_CUSTOM_COMPONENTS##"]) {
+    window["##BUDIBASE_CUSTOM_COMPONENTS##"].forEach(component => {
+      componentStore.actions.registerCustomComponent(component)
+    })
+  }
+
+  // Make a callback available for custom component bundles to register
+  // themselves at runtime
+  window.registerCustomComponent =
+    componentStore.actions.registerCustomComponent
+
+  // Initialise websocket
+  initWebsocket()
+
+  // Create app if one hasn't been created yet
+  if (!app) {
+    app = new ClientApp({
+      target: window.document.body,
+    })
+  }
+}
+
+// Attach to window so the HTML template can call this when it loads
+window.loadBudibase = loadBudibase
diff --git a/packages/client/src/stores/dnd.js b/packages/client/src/stores/dnd.js
index 43d4eeeed8..5cfb12c7d2 100644
--- a/packages/client/src/stores/dnd.js
+++ b/packages/client/src/stores/dnd.js
@@ -21,7 +21,11 @@ const createDndStore = () => {
     })
   }
 
-  const startDraggingNewComponent = ({ component, definition }) => {
+  const startDraggingNewComponent = ({
+    component,
+    definition,
+    componentId,
+  }) => {
     if (!component) {
       return
     }
@@ -38,6 +42,7 @@ const createDndStore = () => {
         bounds: { height, width },
         index: null,
         newComponentType: component,
+        newComponentId: componentId,
       },
     })
   }
@@ -82,6 +87,10 @@ export const dndParent = derivedMemo(dndStore, x => x.drop?.parent)
 export const dndIndex = derivedMemo(dndStore, x => x.drop?.index)
 export const dndBounds = derivedMemo(dndStore, x => x.source?.bounds)
 export const dndIsDragging = derivedMemo(dndStore, x => !!x.source)
+export const dndNewComponentId = derivedMemo(
+  dndStore,
+  x => x.source?.newComponentId
+)
 export const dndIsNewComponent = derivedMemo(
   dndStore,
   x => x.source?.newComponentType != null
diff --git a/packages/client/src/stores/index.js b/packages/client/src/stores/index.js
index f2b80ed732..268b0cc4bf 100644
--- a/packages/client/src/stores/index.js
+++ b/packages/client/src/stores/index.js
@@ -2,7 +2,7 @@ export { authStore } from "./auth"
 export { appStore } from "./app"
 export { notificationStore } from "./notification"
 export { routeStore } from "./routes"
-export { screenStore } from "./screens"
+export { screenStore, isGridScreen } from "./screens"
 export { builderStore } from "./builder"
 export { dataSourceStore } from "./dataSource"
 export { confirmationStore } from "./confirmation"
diff --git a/packages/client/src/stores/screens.js b/packages/client/src/stores/screens.js
index a7277ca2b5..f85675e389 100644
--- a/packages/client/src/stores/screens.js
+++ b/packages/client/src/stores/screens.js
@@ -198,3 +198,7 @@ const createScreenStore = () => {
 }
 
 export const screenStore = createScreenStore()
+
+export const isGridScreen = derived(screenStore, $screenStore => {
+  return $screenStore.activeScreen?.props?.layout === "grid"
+})
diff --git a/packages/client/vite.config.mjs b/packages/client/vite.config.mjs
index 7c163181ae..9ef87d8ec8 100644
--- a/packages/client/vite.config.mjs
+++ b/packages/client/vite.config.mjs
@@ -20,7 +20,7 @@ export default defineConfig(({ mode }) => {
     },
     build: {
       lib: {
-        entry: "src/index.js",
+        entry: "src/index.ts",
         formats: ["iife"],
         outDir: "dist",
         name: "budibase_client",
@@ -67,10 +67,6 @@ export default defineConfig(({ mode }) => {
           find: "constants",
           replacement: path.resolve("./src/constants"),
         },
-        {
-          find: "@/constants",
-          replacement: path.resolve("./src/constants"),
-        },
         {
           find: "sdk",
           replacement: path.resolve("./src/sdk"),
@@ -87,6 +83,10 @@ export default defineConfig(({ mode }) => {
           find: "@budibase/bbui",
           replacement: path.resolve("../bbui/src"),
         },
+        {
+          find: "@",
+          replacement: path.resolve(__dirname, "src"),
+        },
       ],
     },
   }
diff --git a/packages/types/src/ui/components/index.ts b/packages/types/src/ui/components/index.ts
index 283ceb47da..85c7b1af84 100644
--- a/packages/types/src/ui/components/index.ts
+++ b/packages/types/src/ui/components/index.ts
@@ -2,6 +2,16 @@ export * from "./sidepanel"
 export * from "./codeEditor"
 export * from "./errors"
 
+export interface CustomComponent {
+  Component: any
+  schema: {
+    type: "component"
+    metadata: Record<string, any>
+    schema: ComponentDefinition
+  }
+  version: string
+}
+
 export interface ComponentDefinition {
   component: string
   name: string