diff --git a/package.json b/package.json
index d05ed01..4736291 100644
--- a/package.json
+++ b/package.json
@@ -45,6 +45,7 @@
     "react-use": "^17.3.2",
     "react-window": "^1.8.7",
     "styled-components": "^5.3.5",
+    "superstruct": "^1.0.3",
     "webext-domain-permission-toggle": "^3.0.0",
     "webext-dynamic-content-scripts": "^8.1.1",
     "webextension-polyfill": "^0.10.0"
diff --git a/src/platforms/GitHub/DOMHelper.ts b/src/platforms/GitHub/DOMHelper.ts
index 1de1bae..68bb777 100644
--- a/src/platforms/GitHub/DOMHelper.ts
+++ b/src/platforms/GitHub/DOMHelper.ts
@@ -1,9 +1,11 @@
 import { raiseError } from 'analytics'
 import { Clippy, ClippyClassName } from 'components/Clippy'
 import * as React from 'react'
+import * as s from 'superstruct'
 import { $ } from 'utils/$'
 import { formatClass, parseIntFromElement } from 'utils/DOMHelper'
 import { renderReact } from 'utils/general'
+import { embeddedDataStruct } from './embeddedDataStructures'
 
 const selectors = {
   normal: {
@@ -44,16 +46,11 @@ const getDOMJSON = (selector: string) =>
     }
   })
 
-function getMetaFromPayload(payload: any) {
+function getMetaFromPayload(payload: s.Infer<typeof embeddedDataStruct.repoPayload>) {
   const { repo, refInfo } = payload
-  if (!repo || !refInfo) return
-
   const { defaultBranch, name: repoName, ownerLogin: userName } = repo
   const { name: branchName } = refInfo
 
-  // TODO: use runtime type check
-  if (!defaultBranch || !repoName || !userName || !branchName) return
-
   return {
     defaultBranch,
     metaData: {
@@ -66,15 +63,14 @@ function getMetaFromPayload(payload: any) {
 
 // in code page, there is a JSON script tag in DOM with meta data
 function resolveEmbeddedAppData() {
-  const appData = getDOMJSON(selectors.globalNavigation.embeddedData.app)
-  const payload = appData?.payload
-  if (payload) return getMetaFromPayload(payload)
+  const data = getDOMJSON(selectors.globalNavigation.embeddedData.app)
+  if (s.is(data, embeddedDataStruct.app)) return getMetaFromPayload(data.payload)
 }
 
 function resolveEmbeddedReposOverviewData() {
-  const reposOverviewData = getDOMJSON(selectors.globalNavigation.embeddedData.reposOverview)
-  const payload = reposOverviewData?.props?.initialPayload
-  if (payload) return getMetaFromPayload(payload)
+  const data = getDOMJSON(selectors.globalNavigation.embeddedData.reposOverview)
+  if (s.is(data, embeddedDataStruct.reposOverview))
+    return getMetaFromPayload(data.props.initialPayload)
 }
 
 export function resolveEmbeddedData(): {
diff --git a/src/platforms/GitHub/embeddedDataStructures.ts b/src/platforms/GitHub/embeddedDataStructures.ts
new file mode 100644
index 0000000..676b93e
--- /dev/null
+++ b/src/platforms/GitHub/embeddedDataStructures.ts
@@ -0,0 +1,81 @@
+import * as s from 'superstruct'
+
+const repo = s.object({
+  id: s.number(),
+  defaultBranch: s.string(),
+  name: s.string(),
+  ownerLogin: s.string(),
+  currentUserCanPush: s.boolean(),
+  isFork: s.boolean(),
+  isEmpty: s.boolean(),
+  createdAt: s.string(),
+  ownerAvatar: s.string(),
+  public: s.boolean(),
+  private: s.boolean(),
+  isOrgOwned: s.boolean(),
+})
+
+const user = s.object({
+  id: s.number(),
+  login: s.string(),
+  userEmail: s.string(),
+})
+
+const rel = s.object({
+  name: s.string(),
+  listCacheKey: s.string(),
+  canEdit: s.boolean(),
+  refType: s.string(),
+  currentOid: s.string(),
+})
+
+const treeItem = s.object({
+  name: s.string(),
+  path: s.string(),
+  contentType: s.string(),
+})
+
+const tree = s.object({
+  items: s.array(treeItem),
+  templateDirectorySuggestionUrl: s.nullable(s.never()),
+  readme: s.nullable(s.never()),
+  totalCount: s.number(),
+  showBranchInfobar: s.boolean(),
+})
+
+const repoPayload = s.object({
+  allShortcutsEnabled: s.boolean(),
+  path: s.string(),
+  repo: repo,
+  currentUser: user,
+  refInfo: rel,
+  tree: tree,
+  fileTree: s.nullable(s.never()),
+  fileTreeProcessingTime: s.nullable(s.never()),
+  foldersToFetch: s.array(s.unknown()),
+  treeExpanded: s.boolean(),
+  symbolsExpanded: s.boolean(),
+  isOverview: s.boolean(),
+  overview: s.unknown(),
+})
+
+const reposOverview = s.object({
+  props: s.object({
+    initialPayload: repoPayload,
+    appPayload: s.unknown(),
+  }),
+})
+const app = s.object({
+  payload: repoPayload,
+})
+
+export const embeddedDataStruct = {
+  repo,
+  user,
+  rel,
+  treeItem,
+  tree,
+  repoPayload,
+  reposOverview,
+  app,
+}
diff --git a/webpack.config.js b/webpack.config.js
index 30839d9..8a1f1af 100644
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -113,10 +113,10 @@ module.exports = {
         sideEffects: false,
       },
       {
-        test: /\.js$/,
+        test: /\.m?js$/,
         loader: 'babel-loader',
         // Transpile as least files under node_modules
-        include: /node_modules\/(webext-content-scripts|webext-detect-page)\/.*\.js$/,
+        include: /node_modules\/(webext-content-scripts|webext-detect-page|superstruct)\/.*\.m?js$/,
         options: {
           cacheDirectory: true,
         },
diff --git a/yarn.lock b/yarn.lock
index bc5a776..3585039 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -11325,6 +11325,11 @@ stylis@^4.0.6:
   resolved "https://registry.yarnpkg.com/stylis/-/stylis-4.1.1.tgz#e46c6a9bbf7c58db1e65bb730be157311ae1fe12"
   integrity sha512-lVrM/bNdhVX2OgBFNa2YJ9Lxj7kPzylieHd3TNjuGE0Re9JB7joL5VUKOVH1kdNNJTgGPpT8hmwIAPLaSyEVFQ==
 
+superstruct@^1.0.3:
+  version "1.0.3"
+  resolved "https://registry.npmmirror.com/superstruct/-/superstruct-1.0.3.tgz#de626a5b49c6641ff4d37da3c7598e7a87697046"
+  integrity sha512-8iTn3oSS8nRGn+C2pgXSKPI3jmpm6FExNazNpjvqS6ZUJQCej3PUXEKM8NjHBOs54ExM+LPW/FBRhymrdcCiSg==
+
 supports-color@6.1.0:
   version "6.1.0"
   resolved "https://registry.yarnpkg.com/supports-color/-/supports-color-6.1.0.tgz#0764abc69c63d5ac842dd4867e8d025e880df8f3"