diff --git a/packages/runtime-core/README.md b/packages/runtime-core/README.md
index e36fb1cbf..f83b857c4 100644
--- a/packages/runtime-core/README.md
+++ b/packages/runtime-core/README.md
@@ -9,8 +9,7 @@ For full exposed APIs, see `src/index.ts`. You can also run `yarn build runtime-
 ``` ts
 import { createRenderer, createAppAPI } from '@vue/runtime-core'
 
-// low-level render method
-export const render = createRenderer({
+const { render, createApp } = createRenderer({
   pathcProp,
   insert,
   remove,
@@ -18,7 +17,10 @@ export const render = createRenderer({
   // ...
 })
 
-export const createApp = createAppAPI(render)
+// `render` is the low-level API
+// `createApp` returns an app instance with configurable context shared
+// by the entire app tree.
+export { render, createApp }
 
 export * from '@vue/runtime-core'
 ```
diff --git a/packages/runtime-core/src/apiApp.ts b/packages/runtime-core/src/apiApp.ts
index a42c69f2d..6a932822a 100644
--- a/packages/runtime-core/src/apiApp.ts
+++ b/packages/runtime-core/src/apiApp.ts
@@ -2,13 +2,13 @@ import { Component, Data, ComponentInternalInstance } from './component'
 import { ComponentOptions } from './componentOptions'
 import { ComponentPublicInstance } from './componentPublicInstanceProxy'
 import { Directive } from './directives'
-import { HostNode, RootRenderFunction } from './createRenderer'
+import { RootRenderFunction } from './createRenderer'
 import { InjectionKey } from './apiInject'
 import { isFunction } from '@vue/shared'
 import { warn } from './warning'
 import { createVNode } from './vnode'
 
-export interface App {
+export interface App<HostElement = any> {
   config: AppConfig
   use(plugin: Plugin, options?: any): this
   mixin(mixin: ComponentOptions): this
@@ -18,7 +18,7 @@ export interface App {
   directive(name: string, directive: Directive): this
   mount(
     rootComponent: Component,
-    rootContainer: string | HostNode,
+    rootContainer: HostElement,
     rootProps?: Data
   ): ComponentPublicInstance
   provide<T>(key: InjectionKey<T> | string, value: T): void
@@ -70,7 +70,9 @@ export function createAppContext(): AppContext {
   }
 }
 
-export function createAppAPI(render: RootRenderFunction): () => App {
+export function createAppAPI<HostNode, HostElement>(
+  render: RootRenderFunction<HostNode, HostElement>
+): () => App<HostElement> {
   return function createApp(): App {
     const context = createAppContext()
 
@@ -128,7 +130,11 @@ export function createAppAPI(render: RootRenderFunction): () => App {
         }
       },
 
-      mount(rootComponent, rootContainer, rootProps?: Data): any {
+      mount(
+        rootComponent: Component,
+        rootContainer: string | HostElement,
+        rootProps?: Data
+      ): any {
         if (!isMounted) {
           const vnode = createVNode(rootComponent, rootProps)
           // store app context on the root VNode.
diff --git a/packages/runtime-core/src/createRenderer.ts b/packages/runtime-core/src/createRenderer.ts
index 987f0ac7e..614a5ced0 100644
--- a/packages/runtime-core/src/createRenderer.ts
+++ b/packages/runtime-core/src/createRenderer.ts
@@ -38,6 +38,8 @@ import { PatchFlags } from './patchFlags'
 import { ShapeFlags } from './shapeFlags'
 import { pushWarningContext, popWarningContext, warn } from './warning'
 import { invokeDirectiveHook } from './directives'
+import { ComponentPublicInstance } from './componentPublicInstanceProxy'
+import { App, createAppAPI } from './apiApp'
 
 const prodEffectOptions = {
   scheduler: queueJob
@@ -67,40 +69,64 @@ function invokeHooks(hooks: Function[], arg?: any) {
   }
 }
 
-export type HostNode = any
-
-export interface RendererOptions {
+export interface RendererOptions<HostNode = any, HostElement = any> {
   patchProp(
-    el: HostNode,
+    el: HostElement,
     key: string,
     value: any,
     oldValue: any,
     isSVG: boolean,
-    prevChildren?: VNode[],
+    prevChildren?: VNode<HostNode, HostElement>[],
     parentComponent?: ComponentInternalInstance | null,
     unmountChildren?: (
-      children: VNode[],
+      children: VNode<HostNode, HostElement>[],
       parentComponent: ComponentInternalInstance | null
     ) => void
   ): void
-  insert(el: HostNode, parent: HostNode, anchor?: HostNode): void
+  insert(el: HostNode, parent: HostElement, anchor?: HostNode | null): void
   remove(el: HostNode): void
-  createElement(type: string, isSVG?: boolean): HostNode
+  createElement(type: string, isSVG?: boolean): HostElement
   createText(text: string): HostNode
   createComment(text: string): HostNode
   setText(node: HostNode, text: string): void
-  setElementText(node: HostNode, text: string): void
+  setElementText(node: HostElement, text: string): void
   parentNode(node: HostNode): HostNode | null
   nextSibling(node: HostNode): HostNode | null
-  querySelector(selector: string): HostNode | null
+  querySelector(selector: string): HostElement | null
 }
 
-export type RootRenderFunction = (
-  vnode: VNode | null,
-  dom: HostNode | string
+export type RootRenderFunction<HostNode, HostElement> = (
+  vnode: VNode<HostNode, HostElement> | null,
+  dom: HostElement | string
 ) => void
 
-export function createRenderer(options: RendererOptions): RootRenderFunction {
+/**
+ * The createRenderer function accepts two generic arguments:
+ * HostNode and HostElement, corresponding to Node and Element types in the
+ * host environment. For example, for runtime-dom, HostNode would be the DOM
+ * `Node` interface and HostElement would be the DOM `Element` interface.
+ *
+ * Custom renderers can pass in the platform specific types like this:
+ *
+ * ``` js
+ * const { render, createApp } = createRenderer<Node, Element>({
+ *   patchProp,
+ *   ...nodeOps
+ * })
+ * ```
+ */
+export function createRenderer<
+  HostNode extends object = any,
+  HostElement extends HostNode = any
+>(
+  options: RendererOptions<HostNode, HostElement>
+): {
+  render: RootRenderFunction<HostNode, HostElement>
+  createApp: () => App<HostElement>
+} {
+  type HostVNode = VNode<HostNode, HostElement>
+  type HostVNodeChildren = VNodeChildren<HostNode, HostElement>
+
   const {
     insert: hostInsert,
     remove: hostRemove,
@@ -116,10 +142,10 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
   } = options
 
   function patch(
-    n1: VNode | null, // null means this is a mount
-    n2: VNode,
-    container: HostNode,
-    anchor: HostNode = null,
+    n1: HostVNode | null, // null means this is a mount
+    n2: HostVNode,
+    container: HostElement,
+    anchor: HostNode | null = null,
     parentComponent: ComponentInternalInstance | null = null,
     isSVG: boolean = false,
     optimized: boolean = false
@@ -183,16 +209,16 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
             optimized
           )
         } else if (__DEV__) {
-          warn('Invalid VNode type:', n2.type, `(${typeof n2.type})`)
+          warn('Invalid HostVNode type:', n2.type, `(${typeof n2.type})`)
         }
     }
   }
 
   function processText(
-    n1: VNode | null,
-    n2: VNode,
-    container: HostNode,
-    anchor: HostNode
+    n1: HostVNode | null,
+    n2: HostVNode,
+    container: HostElement,
+    anchor: HostNode | null
   ) {
     if (n1 == null) {
       hostInsert(
@@ -201,7 +227,7 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
         anchor
       )
     } else {
-      const el = (n2.el = n1.el)
+      const el = (n2.el = n1.el) as HostNode
       if (n2.children !== n1.children) {
         hostSetText(el, n2.children as string)
       }
@@ -209,10 +235,10 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
   }
 
   function processEmptyNode(
-    n1: VNode | null,
-    n2: VNode,
-    container: HostNode,
-    anchor: HostNode
+    n1: HostVNode | null,
+    n2: HostVNode,
+    container: HostElement,
+    anchor: HostNode | null
   ) {
     if (n1 == null) {
       hostInsert((n2.el = hostCreateComment('')), container, anchor)
@@ -222,10 +248,10 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
   }
 
   function processElement(
-    n1: VNode | null,
-    n2: VNode,
-    container: HostNode,
-    anchor: HostNode,
+    n1: HostVNode | null,
+    n2: HostVNode,
+    container: HostElement,
+    anchor: HostNode | null,
     parentComponent: ComponentInternalInstance | null,
     isSVG: boolean,
     optimized: boolean
@@ -241,9 +267,9 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
   }
 
   function mountElement(
-    vnode: VNode,
-    container: HostNode,
-    anchor: HostNode,
+    vnode: HostVNode,
+    container: HostElement,
+    anchor: HostNode | null,
     parentComponent: ComponentInternalInstance | null,
     isSVG: boolean
   ) {
@@ -264,7 +290,7 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
       hostSetElementText(el, vnode.children as string)
     } else if (shapeFlag & ShapeFlags.ARRAY_CHILDREN) {
       mountChildren(
-        vnode.children as VNodeChildren,
+        vnode.children as HostVNodeChildren,
         el,
         null,
         parentComponent,
@@ -280,9 +306,9 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
   }
 
   function mountChildren(
-    children: VNodeChildren,
-    container: HostNode,
-    anchor: HostNode,
+    children: HostVNodeChildren,
+    container: HostElement,
+    anchor: HostNode | null,
     parentComponent: ComponentInternalInstance | null,
     isSVG: boolean,
     start: number = 0
@@ -294,13 +320,13 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
   }
 
   function patchElement(
-    n1: VNode,
-    n2: VNode,
+    n1: HostVNode,
+    n2: HostVNode,
     parentComponent: ComponentInternalInstance | null,
     isSVG: boolean,
     optimized: boolean
   ) {
-    const el = (n2.el = n1.el)
+    const el = (n2.el = n1.el) as HostElement
     const { patchFlag, dynamicChildren } = n2
     const oldProps = (n1 && n1.props) || EMPTY_OBJ
     const newProps = n2.props || EMPTY_OBJ
@@ -353,7 +379,7 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
                 next,
                 prev,
                 isSVG,
-                n1.children as VNode[],
+                n1.children as HostVNode[],
                 parentComponent,
                 unmountChildren
               )
@@ -378,7 +404,7 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
 
     if (dynamicChildren != null) {
       // children fast path
-      const olddynamicChildren = n1.dynamicChildren as VNode[]
+      const olddynamicChildren = n1.dynamicChildren as HostVNode[]
       for (let i = 0; i < dynamicChildren.length; i++) {
         patch(
           olddynamicChildren[i],
@@ -403,8 +429,8 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
   }
 
   function patchProps(
-    el: HostNode,
-    vnode: VNode,
+    el: HostElement,
+    vnode: HostVNode,
     oldProps: any,
     newProps: any,
     parentComponent: ComponentInternalInstance | null,
@@ -422,7 +448,7 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
             next,
             prev,
             isSVG,
-            vnode.children as VNode[],
+            vnode.children as HostVNode[],
             parentComponent,
             unmountChildren
           )
@@ -438,7 +464,7 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
               null,
               null,
               isSVG,
-              vnode.children as VNode[],
+              vnode.children as HostVNode[],
               parentComponent,
               unmountChildren
             )
@@ -449,24 +475,26 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
   }
 
   function processFragment(
-    n1: VNode | null,
-    n2: VNode,
-    container: HostNode,
-    anchor: HostNode,
+    n1: HostVNode | null,
+    n2: HostVNode,
+    container: HostElement,
+    anchor: HostNode | null,
     parentComponent: ComponentInternalInstance | null,
     isSVG: boolean,
     optimized: boolean
   ) {
-    const fragmentStartAnchor = (n2.el = n1 ? n1.el : hostCreateComment(''))
+    const fragmentStartAnchor = (n2.el = n1
+      ? n1.el
+      : hostCreateComment('')) as HostNode
     const fragmentEndAnchor = (n2.anchor = n1
       ? n1.anchor
-      : hostCreateComment(''))
+      : hostCreateComment('')) as HostNode
     if (n1 == null) {
       hostInsert(fragmentStartAnchor, container, anchor)
       hostInsert(fragmentEndAnchor, container, anchor)
       // a fragment can only have array children
       mountChildren(
-        n2.children as VNodeChildren,
+        n2.children as HostVNodeChildren,
         container,
         fragmentEndAnchor,
         parentComponent,
@@ -486,10 +514,10 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
   }
 
   function processPortal(
-    n1: VNode | null,
-    n2: VNode,
-    container: HostNode,
-    anchor: HostNode,
+    n1: HostVNode | null,
+    n2: HostVNode,
+    container: HostElement,
+    anchor: HostNode | null,
     parentComponent: ComponentInternalInstance | null,
     isSVG: boolean,
     optimized: boolean
@@ -505,7 +533,7 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
           hostSetElementText(target, children as string)
         } else if (shapeFlag & ShapeFlags.ARRAY_CHILDREN) {
           mountChildren(
-            children as VNodeChildren,
+            children as HostVNodeChildren,
             target,
             null,
             parentComponent,
@@ -517,7 +545,7 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
       }
     } else {
       // update content
-      const target = (n2.target = n1.target)
+      const target = (n2.target = n1.target) as HostElement
       if (patchFlag === PatchFlags.TEXT) {
         hostSetElementText(target, children as string)
       } else if (!optimized) {
@@ -534,8 +562,8 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
             hostSetElementText(target, '')
             hostSetElementText(nextTarget, children as string)
           } else if (shapeFlag & ShapeFlags.ARRAY_CHILDREN) {
-            for (let i = 0; i < (children as VNode[]).length; i++) {
-              move((children as VNode[])[i], nextTarget, null)
+            for (let i = 0; i < (children as HostVNode[]).length; i++) {
+              move((children as HostVNode[])[i], nextTarget, null)
             }
           }
         } else if (__DEV__) {
@@ -548,10 +576,10 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
   }
 
   function processComponent(
-    n1: VNode | null,
-    n2: VNode,
-    container: HostNode,
-    anchor: HostNode,
+    n1: HostVNode | null,
+    n2: HostVNode,
+    container: HostElement,
+    anchor: HostNode | null,
     parentComponent: ComponentInternalInstance | null,
     isSVG: boolean,
     optimized: boolean
@@ -580,9 +608,9 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
   }
 
   function mountComponent(
-    initialVNode: VNode,
-    container: HostNode,
-    anchor: HostNode,
+    initialVNode: HostVNode,
+    container: HostElement,
+    anchor: HostNode | null,
     parentComponent: ComponentInternalInstance | null,
     isSVG: boolean
   ) {
@@ -624,7 +652,7 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
       } else {
         // updateComponent
         // This is triggered by mutation of component's own state (next: null)
-        // OR parent calling processComponent (next: VNode)
+        // OR parent calling processComponent (next: HostVNode)
         const { next } = instance
 
         if (__DEV__) {
@@ -654,7 +682,7 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
           prevTree,
           nextTree,
           // parent may have changed if it's in a portal
-          hostParentNode(prevTree.el),
+          hostParentNode(prevTree.el as HostNode) as HostElement,
           // anchor may have changed if it's in a fragment
           getNextHostNode(prevTree),
           instance,
@@ -689,10 +717,10 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
   }
 
   function patchChildren(
-    n1: VNode | null,
-    n2: VNode,
-    container: HostNode,
-    anchor: HostNode,
+    n1: HostVNode | null,
+    n2: HostVNode,
+    container: HostElement,
+    anchor: HostNode | null,
     parentComponent: ComponentInternalInstance | null,
     isSVG: boolean,
     optimized: boolean = false
@@ -708,8 +736,8 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
         // this could be either fully-keyed or mixed (some keyed some not)
         // presence of patchFlag means children are guaranteed to be arrays
         patchKeyedChildren(
-          c1 as VNode[],
-          c2 as VNodeChildren,
+          c1 as HostVNode[],
+          c2 as HostVNodeChildren,
           container,
           anchor,
           parentComponent,
@@ -720,8 +748,8 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
       } else if (patchFlag & PatchFlags.UNKEYED) {
         // unkeyed
         patchUnkeyedChildren(
-          c1 as VNode[],
-          c2 as VNodeChildren,
+          c1 as HostVNode[],
+          c2 as HostVNodeChildren,
           container,
           anchor,
           parentComponent,
@@ -735,7 +763,7 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
     if (shapeFlag & ShapeFlags.TEXT_CHILDREN) {
       // text children fast path
       if (prevShapeFlag & ShapeFlags.ARRAY_CHILDREN) {
-        unmountChildren(c1 as VNode[], parentComponent)
+        unmountChildren(c1 as HostVNode[], parentComponent)
       }
       if (c2 !== c1) {
         hostSetElementText(container, c2 as string)
@@ -745,7 +773,7 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
         hostSetElementText(container, '')
         if (shapeFlag & ShapeFlags.ARRAY_CHILDREN) {
           mountChildren(
-            c2 as VNodeChildren,
+            c2 as HostVNodeChildren,
             container,
             anchor,
             parentComponent,
@@ -756,8 +784,8 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
         if (shapeFlag & ShapeFlags.ARRAY_CHILDREN) {
           // two arrays, cannot assume anything, do full diff
           patchKeyedChildren(
-            c1 as VNode[],
-            c2 as VNodeChildren,
+            c1 as HostVNode[],
+            c2 as HostVNodeChildren,
             container,
             anchor,
             parentComponent,
@@ -766,17 +794,17 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
           )
         } else {
           // c2 is null in this case
-          unmountChildren(c1 as VNode[], parentComponent, true)
+          unmountChildren(c1 as HostVNode[], parentComponent, true)
         }
       }
     }
   }
 
   function patchUnkeyedChildren(
-    c1: VNode[],
-    c2: VNodeChildren,
-    container: HostNode,
-    anchor: HostNode,
+    c1: HostVNode[],
+    c2: HostVNodeChildren,
+    container: HostElement,
+    anchor: HostNode | null,
     parentComponent: ComponentInternalInstance | null,
     isSVG: boolean,
     optimized: boolean
@@ -810,10 +838,10 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
 
   // can be all-keyed or mixed
   function patchKeyedChildren(
-    c1: VNode[],
-    c2: VNodeChildren,
-    container: HostNode,
-    parentAnchor: HostNode,
+    c1: HostVNode[],
+    c2: HostVNodeChildren,
+    container: HostElement,
+    parentAnchor: HostNode | null,
     parentComponent: ComponentInternalInstance | null,
     isSVG: boolean,
     optimized: boolean
@@ -878,7 +906,8 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
     if (i > e1) {
       if (i <= e2) {
         const nextPos = e2 + 1
-        const anchor = nextPos < l2 ? (c2[nextPos] as VNode).el : parentAnchor
+        const anchor =
+          nextPos < l2 ? (c2[nextPos] as HostVNode).el : parentAnchor
         while (i <= e2) {
           patch(
             null,
@@ -960,7 +989,7 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
         } else {
           // key-less node, try to locate a key-less node of the same type
           for (j = s2; j <= e2; j++) {
-            if (isSameType(prevChild, c2[j] as VNode)) {
+            if (isSameType(prevChild, c2[j] as HostVNode)) {
               newIndex = j
               break
             }
@@ -977,7 +1006,7 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
           }
           patch(
             prevChild,
-            c2[newIndex] as VNode,
+            c2[newIndex] as HostVNode,
             container,
             null,
             parentComponent,
@@ -997,9 +1026,11 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
       // looping backwards so that we can use last patched node as anchor
       for (i = toBePatched - 1; i >= 0; i--) {
         const nextIndex = s2 + i
-        const nextChild = c2[nextIndex] as VNode
+        const nextChild = c2[nextIndex] as HostVNode
         const anchor =
-          nextIndex + 1 < l2 ? (c2[nextIndex + 1] as VNode).el : parentAnchor
+          nextIndex + 1 < l2
+            ? (c2[nextIndex + 1] as HostVNode).el
+            : parentAnchor
         if (newIndexToOldIndexMap[i] === 0) {
           // mount new
           patch(null, nextChild, container, anchor, parentComponent, isSVG)
@@ -1017,25 +1048,29 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
     }
   }
 
-  function move(vnode: VNode, container: HostNode, anchor: HostNode) {
+  function move(
+    vnode: HostVNode,
+    container: HostElement,
+    anchor: HostNode | null
+  ) {
     if (vnode.component !== null) {
       move(vnode.component.subTree, container, anchor)
       return
     }
     if (vnode.type === Fragment) {
-      hostInsert(vnode.el, container, anchor)
-      const children = vnode.children as VNode[]
+      hostInsert(vnode.el as HostNode, container, anchor)
+      const children = vnode.children as HostVNode[]
       for (let i = 0; i < children.length; i++) {
-        hostInsert(children[i].el, container, anchor)
+        hostInsert(children[i].el as HostNode, container, anchor)
       }
-      hostInsert(vnode.anchor, container, anchor)
+      hostInsert(vnode.anchor as HostNode, container, anchor)
     } else {
-      hostInsert(vnode.el, container, anchor)
+      hostInsert(vnode.el as HostNode, container, anchor)
     }
   }
 
   function unmount(
-    vnode: VNode,
+    vnode: HostVNode,
     parentComponent: ComponentInternalInstance | null,
     doRemove?: boolean
   ) {
@@ -1069,14 +1104,14 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
       unmountChildren(dynamicChildren, parentComponent, shouldRemoveChildren)
     } else if (shapeFlag & ShapeFlags.ARRAY_CHILDREN) {
       unmountChildren(
-        children as VNode[],
+        children as HostVNode[],
         parentComponent,
         shouldRemoveChildren
       )
     }
 
     if (doRemove) {
-      hostRemove(vnode.el)
+      hostRemove(vnode.el as HostNode)
       if (anchor != null) hostRemove(anchor)
     }
 
@@ -1110,7 +1145,7 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
   }
 
   function unmountChildren(
-    children: VNode[],
+    children: HostVNode[],
     parentComponent: ComponentInternalInstance | null,
     doRemove?: boolean,
     start: number = 0
@@ -1120,9 +1155,9 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
     }
   }
 
-  function getNextHostNode(vnode: VNode): HostNode {
+  function getNextHostNode(vnode: HostVNode): HostNode | null {
     return vnode.component === null
-      ? hostNextSibling(vnode.anchor || vnode.el)
+      ? hostNextSibling((vnode.anchor || vnode.el) as HostNode)
       : getNextHostNode(vnode.component.subTree)
   }
 
@@ -1130,7 +1165,7 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
     ref: string | Function | Ref<any>,
     oldRef: string | Function | Ref<any> | null,
     parent: ComponentInternalInstance,
-    value: HostNode | ComponentInternalInstance | null
+    value: HostNode | ComponentPublicInstance | null
   ) {
     const refs = parent.refs === EMPTY_OBJ ? (parent.refs = {}) : parent.refs
     const renderContext = toRaw(parent.renderContext)
@@ -1163,39 +1198,33 @@ export function createRenderer(options: RendererOptions): RootRenderFunction {
     }
   }
 
-  return function render(vnode: VNode | null, dom: HostNode | string) {
-    if (isString(dom)) {
-      if (isFunction(hostQuerySelector)) {
-        dom = hostQuerySelector(dom)
-        if (!dom) {
-          if (__DEV__) {
-            warn(
-              `Failed to locate root container: ` +
-                `querySelector returned null.`
-            )
-          }
-          return
-        }
-      } else {
+  function render(vnode: HostVNode | null, rawContainer: HostElement | string) {
+    let container: any = rawContainer
+    if (isString(container)) {
+      container = hostQuerySelector(container)
+      if (!container) {
         if (__DEV__) {
           warn(
-            `Failed to locate root container: ` +
-              `target platform does not support querySelector.`
+            `Failed to locate root container: ` + `querySelector returned null.`
           )
         }
         return
       }
     }
     if (vnode == null) {
-      debugger
-      if (dom._vnode) {
-        unmount(dom._vnode, null, true)
+      if (container._vnode) {
+        unmount(container._vnode, null, true)
       }
     } else {
-      patch(dom._vnode, vnode, dom)
+      patch(container._vnode || null, vnode, container)
     }
     flushPostFlushCbs()
-    dom._vnode = vnode
+    container._vnode = vnode
+  }
+
+  return {
+    render,
+    createApp: createAppAPI(render)
   }
 }
 
diff --git a/packages/runtime-core/src/directives.ts b/packages/runtime-core/src/directives.ts
index 6acf27c4a..2119bec9d 100644
--- a/packages/runtime-core/src/directives.ts
+++ b/packages/runtime-core/src/directives.ts
@@ -17,7 +17,6 @@ import { warn } from './warning'
 import { ComponentInternalInstance } from './component'
 import { currentRenderingInstance } from './componentRenderUtils'
 import { callWithAsyncErrorHandling, ErrorCodes } from './errorHandling'
-import { HostNode } from './createRenderer'
 import { ComponentPublicInstance } from './componentPublicInstanceProxy'
 
 export interface DirectiveBinding {
@@ -29,7 +28,7 @@ export interface DirectiveBinding {
 }
 
 export type DirectiveHook = (
-  el: HostNode,
+  el: any,
   binding: DirectiveBinding,
   vnode: VNode,
   prevVNode: VNode | null
diff --git a/packages/runtime-core/src/index.ts b/packages/runtime-core/src/index.ts
index 46d0406fd..365b23f1b 100644
--- a/packages/runtime-core/src/index.ts
+++ b/packages/runtime-core/src/index.ts
@@ -28,7 +28,6 @@ export { PublicShapeFlags as ShapeFlags } from './shapeFlags'
 export { getCurrentInstance } from './component'
 
 // For custom renderers
-export { createAppAPI } from './apiApp'
 export { createRenderer } from './createRenderer'
 export {
   handleError,
diff --git a/packages/runtime-core/src/vnode.ts b/packages/runtime-core/src/vnode.ts
index f81533e75..bd398f05f 100644
--- a/packages/runtime-core/src/vnode.ts
+++ b/packages/runtime-core/src/vnode.ts
@@ -7,17 +7,16 @@ import {
   extend
 } from '@vue/shared'
 import { ComponentInternalInstance, Data, SetupProxySymbol } from './component'
-import { HostNode } from './createRenderer'
 import { RawSlots } from './componentSlots'
 import { PatchFlags } from './patchFlags'
 import { ShapeFlags } from './shapeFlags'
 import { isReactive } from '@vue/reactivity'
 import { AppContext } from './apiApp'
 
-export const Fragment = Symbol('Fragment')
-export const Text = Symbol('Text')
-export const Empty = Symbol('Empty')
-export const Portal = Symbol('Portal')
+export const Fragment = __DEV__ ? Symbol('Fragment') : Symbol()
+export const Text = __DEV__ ? Symbol('Text') : Symbol()
+export const Empty = __DEV__ ? Symbol('Empty') : Symbol()
+export const Portal = __DEV__ ? Symbol('Portal') : Symbol()
 
 export type VNodeTypes =
   | string
@@ -28,24 +27,42 @@ export type VNodeTypes =
   | typeof Text
   | typeof Empty
 
-type VNodeChildAtom = VNode | string | number | boolean | null | void
-export interface VNodeChildren extends Array<VNodeChildren | VNodeChildAtom> {}
-export type VNodeChild = VNodeChildAtom | VNodeChildren
+type VNodeChildAtom<HostNode, HostElement> =
+  | VNode<HostNode, HostElement>
+  | string
+  | number
+  | boolean
+  | null
+  | void
 
-export type NormalizedChildren = string | VNodeChildren | RawSlots | null
+export interface VNodeChildren<HostNode = any, HostElement = any>
+  extends Array<
+      | VNodeChildren<HostNode, HostElement>
+      | VNodeChildAtom<HostNode, HostElement>
+    > {}
 
-export interface VNode {
+export type VNodeChild<HostNode = any, HostElement = any> =
+  | VNodeChildAtom<HostNode, HostElement>
+  | VNodeChildren<HostNode, HostElement>
+
+export type NormalizedChildren<HostNode, HostElement> =
+  | string
+  | VNodeChildren<HostNode, HostElement>
+  | RawSlots
+  | null
+
+export interface VNode<HostNode = any, HostElement = any> {
   type: VNodeTypes
   props: Record<any, any> | null
   key: string | number | null
   ref: string | Function | null
-  children: NormalizedChildren
+  children: NormalizedChildren<HostNode, HostElement>
   component: ComponentInternalInstance | null
 
   // DOM
   el: HostNode | null
   anchor: HostNode | null // fragment anchor
-  target: HostNode | null // portal target
+  target: HostElement | null // portal target
 
   // optimization only
   shapeFlag: number
@@ -209,7 +226,7 @@ export function cloneVNode(vnode: VNode): VNode {
   }
 }
 
-export function normalizeVNode(child: VNodeChild): VNode {
+export function normalizeVNode(child: VNodeChild<any, any>): VNode {
   if (child == null) {
     // empty placeholder
     return createVNode(Empty)
@@ -241,7 +258,7 @@ export function normalizeChildren(vnode: VNode, children: unknown) {
     children = isString(children) ? children : children + ''
     type = ShapeFlags.TEXT_CHILDREN
   }
-  vnode.children = children as NormalizedChildren
+  vnode.children = children as NormalizedChildren<any, any>
   vnode.shapeFlag |= type
 }
 
diff --git a/packages/runtime-dom/src/index.ts b/packages/runtime-dom/src/index.ts
index d3f4fc875..7cb88d260 100644
--- a/packages/runtime-dom/src/index.ts
+++ b/packages/runtime-dom/src/index.ts
@@ -1,14 +1,18 @@
-import { createRenderer, VNode, createAppAPI } from '@vue/runtime-core'
+import { createRenderer } from '@vue/runtime-core'
 import { nodeOps } from './nodeOps'
 import { patchProp } from './patchProp'
 
-export const render = createRenderer({
+const { render, createApp } = createRenderer<Node, Element>({
   patchProp,
   ...nodeOps
-}) as (vnode: VNode | null, container: HTMLElement) => void
+})
 
-export const createApp = createAppAPI(render)
+export { render, createApp }
 
 // re-export everything from core
 // h, Component, reactivity API, nextTick, flags & types
 export * from '@vue/runtime-core'
+
+export interface ComponentPublicInstance {
+  $el: Element
+}
diff --git a/packages/runtime-dom/src/modules/events.ts b/packages/runtime-dom/src/modules/events.ts
index f283b9922..d9d03c5c4 100644
--- a/packages/runtime-dom/src/modules/events.ts
+++ b/packages/runtime-dom/src/modules/events.ts
@@ -45,7 +45,7 @@ export function patchEvent(
   name: string,
   prevValue: EventValue | null,
   nextValue: EventValue | null,
-  instance: ComponentInternalInstance | null
+  instance: ComponentInternalInstance | null = null
 ) {
   const invoker = prevValue && prevValue.invoker
   if (nextValue) {
diff --git a/packages/runtime-dom/src/nodeOps.ts b/packages/runtime-dom/src/nodeOps.ts
index 9316571f9..e7b3e86b7 100644
--- a/packages/runtime-dom/src/nodeOps.ts
+++ b/packages/runtime-dom/src/nodeOps.ts
@@ -36,5 +36,6 @@ export const nodeOps = {
 
   nextSibling: (node: Node): Node | null => node.nextSibling,
 
-  querySelector: (selector: string): Node | null => doc.querySelector(selector)
+  querySelector: (selector: string): Element | null =>
+    doc.querySelector(selector)
 }
diff --git a/packages/runtime-dom/src/patchProp.ts b/packages/runtime-dom/src/patchProp.ts
index 51f780e98..a634cd98f 100644
--- a/packages/runtime-dom/src/patchProp.ts
+++ b/packages/runtime-dom/src/patchProp.ts
@@ -4,7 +4,7 @@ import { patchAttr } from './modules/attrs'
 import { patchDOMProp } from './modules/props'
 import { patchEvent } from './modules/events'
 import { isOn } from '@vue/shared'
-import { VNode } from '@vue/runtime-core'
+import { VNode, ComponentInternalInstance } from '@vue/runtime-core'
 
 export function patchProp(
   el: Element,
@@ -13,7 +13,7 @@ export function patchProp(
   prevValue: any,
   isSVG: boolean,
   prevChildren?: VNode[],
-  parentComponent?: any,
+  parentComponent?: ComponentInternalInstance,
   unmountChildren?: any
 ) {
   switch (key) {
diff --git a/packages/runtime-test/src/index.ts b/packages/runtime-test/src/index.ts
index fc1e440dd..34df836fe 100644
--- a/packages/runtime-test/src/index.ts
+++ b/packages/runtime-test/src/index.ts
@@ -1,14 +1,14 @@
-import { createRenderer, VNode, createAppAPI } from '@vue/runtime-core'
-import { nodeOps, TestElement } from './nodeOps'
+import { createRenderer, VNode } from '@vue/runtime-core'
+import { nodeOps, TestNode, TestElement } from './nodeOps'
 import { patchProp } from './patchProp'
 import { serializeInner } from './serialize'
 
-export const render = createRenderer({
+const { render, createApp } = createRenderer<TestNode, TestElement>({
   patchProp,
   ...nodeOps
-}) as (node: VNode | null, container: TestElement) => void
+})
 
-export const createApp = createAppAPI(render)
+export { render, createApp }
 
 // convenience for one-off render validations
 export function renderToString(vnode: VNode) {
diff --git a/packages/runtime-test/src/nodeOps.ts b/packages/runtime-test/src/nodeOps.ts
index be98f9fcb..41e2c3967 100644
--- a/packages/runtime-test/src/nodeOps.ts
+++ b/packages/runtime-test/src/nodeOps.ts
@@ -218,7 +218,7 @@ function nextSibling(node: TestNode): TestNode | null {
   return parent.children[i + 1] || null
 }
 
-function querySelector() {
+function querySelector(): any {
   throw new Error('querySelector not supported in test renderer.')
 }