diff --git a/server/api/github.ts b/server/api/github.ts
index c29e9c1..559eebf 100644
--- a/server/api/github.ts
+++ b/server/api/github.ts
@@ -19,7 +19,7 @@ async function oauth(code: string) {
   })
 
   const body = await res.json()
-  const { access_token: accessToken, scope, error_description: errorDescription } = body
+  const { accessToken, scope, error_description: errorDescription } = body
   if (errorDescription) {
     throw new Error(errorDescription)
   } else if (scope !== 'repo' || !accessToken || !(typeof accessToken === 'string')) {
diff --git a/src/components/FileExplorer.tsx b/src/components/FileExplorer.tsx
index faedc5f..b2311c7 100644
--- a/src/components/FileExplorer.tsx
+++ b/src/components/FileExplorer.tsx
@@ -37,7 +37,7 @@ const RawFileExplorer: React.FC<Props & ConnectorState> = function RawFileExplor
   React.useEffect(() => {
     const { setUpTree, treeRoot, metaData } = props
     setUpTree({ treeRoot, metaData, config })
-  }, [setUpTree, treeRoot, config.compressSingletonFolder, config.access_token])
+  }, [setUpTree, treeRoot, config.compressSingletonFolder, config.accessToken])
 
   React.useEffect(() => {
     if (visibleNodes?.focusedNode) focusFileExplorer()
diff --git a/src/components/SideBar.tsx b/src/components/SideBar.tsx
index 87165e3..9aa21ca 100644
--- a/src/components/SideBar.tsx
+++ b/src/components/SideBar.tsx
@@ -27,7 +27,7 @@ import { Theme } from './Theme'
 
 const RawGitako: React.FC<Props & ConnectorState> = function RawGitako(props) {
   const configContext = useConfigs()
-  const accessToken = props.configContext.val.access_token
+  const accessToken = props.configContext.val.accessToken
   const [baseSize] = React.useState(() => configContext.val.sideBarWidth)
 
   const { shrinkGitHubHeader } = configContext.val
@@ -52,8 +52,8 @@ const RawGitako: React.FC<Props & ConnectorState> = function RawGitako(props) {
     const { init } = props
     ;(async function () {
       if (!accessToken) {
-        const accessToken = await trySetUpAccessTokenWithCode()
-        configContext.set({ access_token: accessToken || undefined })
+        const accessToken = (await trySetUpAccessTokenWithCode()) || undefined
+        configContext.set({ accessToken })
       }
       init()
     })()
diff --git a/src/components/settings/AccessTokenSettings.tsx b/src/components/settings/AccessTokenSettings.tsx
index 4c56dbb..8bb40dc 100644
--- a/src/components/settings/AccessTokenSettings.tsx
+++ b/src/components/settings/AccessTokenSettings.tsx
@@ -14,7 +14,7 @@ type Props = {}
 
 export function AccessTokenSettings(props: React.PropsWithChildren<Props>) {
   const configContext = useConfigs()
-  const hasAccessToken = Boolean(configContext.val.access_token)
+  const hasAccessToken = Boolean(configContext.val.accessToken)
   const useAccessToken = useStates('')
   const useAccessTokenHint = useStates<React.ReactNode>('')
   const focusInput = useStates(false)
@@ -25,7 +25,7 @@ export function AccessTokenSettings(props: React.PropsWithChildren<Props>) {
   React.useEffect(() => {
     // clear input when access token updates
     useAccessToken.set('')
-  }, [configContext.val.access_token])
+  }, [configContext.val.accessToken])
 
   const onInputAccessToken = React.useCallback(
     ({ currentTarget: { value } }: React.FormEvent<HTMLInputElement>) => {
@@ -44,7 +44,7 @@ export function AccessTokenSettings(props: React.PropsWithChildren<Props>) {
   const saveToken = React.useCallback(
     async (hint?: typeof useAccessTokenHint.val) => {
       if (accessToken) {
-        configContext.set({ access_token: accessToken })
+        configContext.set({ accessToken })
         useAccessToken.set('')
         useAccessTokenHint.set(
           hint || (
@@ -79,7 +79,7 @@ export function AccessTokenSettings(props: React.PropsWithChildren<Props>) {
       {hasAccessToken ? (
         <div>
           <Text as="p">Your token has been saved.</Text>
-          <Button onClick={() => configContext.set({ access_token: '' })}>Clear</Button>
+          <Button onClick={() => configContext.set({ accessToken: '' })}>Clear</Button>
         </div>
       ) : (
         <div>
diff --git a/src/driver/core/FileExplorer.ts b/src/driver/core/FileExplorer.ts
index cebb9fa..a28f651 100644
--- a/src/driver/core/FileExplorer.ts
+++ b/src/driver/core/FileExplorer.ts
@@ -45,9 +45,9 @@ let visibleNodesGenerator: VisibleNodesGenerator
 
 type BoundMethodCreator<Args extends any[] = []> = MethodCreator<Props, ConnectorState, Args>
 
-export const setUpTree: BoundMethodCreator<[
-  Pick<Props, 'treeRoot' | 'metaData'> & { config: Config },
-]> = dispatch => async ({ treeRoot, metaData, config }) => {
+export const setUpTree: BoundMethodCreator<
+  [Pick<Props, 'treeRoot' | 'metaData'> & { config: Config }]
+> = dispatch => async ({ treeRoot, metaData, config }) => {
   if (!treeRoot) return
   dispatch.set({ state: 'rendering' })
 
@@ -57,7 +57,7 @@ export const setUpTree: BoundMethodCreator<[
     root: treeRoot,
     compress: compressSingletonFolder,
     async getTreeData(path) {
-      const { root } = await platform.getTreeData(metaData, path, false, config.access_token)
+      const { root } = await platform.getTreeData(metaData, path, false, config.accessToken)
       return root
     },
   })
@@ -205,12 +205,14 @@ export const setExpand: BoundMethodCreator<[TreeNode, boolean]> = dispatch => as
   dispatch.call(focusNode, node)
 }
 
-export const toggleNodeExpansion: BoundMethodCreator<[
-  TreeNode,
-  {
-    recursive?: boolean
-  },
-]> = dispatch => async (node, { recursive = false }) => {
+export const toggleNodeExpansion: BoundMethodCreator<
+  [
+    TreeNode,
+    {
+      recursive?: boolean
+    },
+  ]
+> = dispatch => async (node, { recursive = false }) => {
   visibleNodesGenerator.focusNode(node)
   await visibleNodesGenerator.toggleExpand(node, recursive)
 }
@@ -221,10 +223,9 @@ export const focusNode: BoundMethodCreator<[TreeNode | null]> = dispatch => (
   visibleNodesGenerator.focusNode(node)
 }
 
-export const onNodeClick: BoundMethodCreator<[
-  React.MouseEvent<HTMLElement, MouseEvent>,
-  TreeNode,
-]> = dispatch => (event, node) => {
+export const onNodeClick: BoundMethodCreator<
+  [React.MouseEvent<HTMLElement, MouseEvent>, TreeNode]
+> = dispatch => (event, node) => {
   const preventDefault = !(node.type === 'blob' && node.url?.includes('#'))
   if (preventDefault) event.preventDefault()
 
diff --git a/src/driver/core/SideBar.ts b/src/driver/core/SideBar.ts
index bd98e77..aec4513 100644
--- a/src/driver/core/SideBar.ts
+++ b/src/driver/core/SideBar.ts
@@ -64,7 +64,7 @@ export const init: BoundMethodCreator = dispatch => async () => {
     const {
       props: { configContext },
     } = dispatch.get()
-    const { access_token: accessToken } = configContext.val
+    const { accessToken } = configContext.val
 
     if (!metaData.userName || !metaData.repoName) return
     const guessDefaultBranch = 'master'
@@ -152,7 +152,7 @@ export const handleError: BoundMethodCreator<[Error]> = dispatch => async err =>
     dispatch.set({ errorDueToAuth: true })
   } else if (err.message === errors.CONNECTION_BLOCKED) {
     const { props } = dispatch.get()
-    if (props.configContext.val.access_token) {
+    if (props.configContext.val.accessToken) {
       dispatch.call(setError, `Cannot connect to ${platformName}.`)
     } else {
       dispatch.set({ errorDueToAuth: true })
@@ -181,9 +181,9 @@ export const toggleShowSideBar: BoundMethodCreator = dispatch => () => {
   }
 }
 
-export const setShouldShow: BoundMethodCreator<[
-  ConnectorState['shouldShow'],
-]> = dispatch => shouldShow => {
+export const setShouldShow: BoundMethodCreator<
+  [ConnectorState['shouldShow']]
+> = dispatch => shouldShow => {
   dispatch.set({ shouldShow }, shouldShow ? DOMHelper.focusFileExplorer : undefined)
   DOMHelper.setBodyIndent(shouldShow)
 }
diff --git a/src/utils/configHelper.ts b/src/utils/configHelper.ts
index e587dae..c6cb4b0 100644
--- a/src/utils/configHelper.ts
+++ b/src/utils/configHelper.ts
@@ -3,7 +3,7 @@ import * as storageHelper from 'utils/storageHelper'
 export type Config = {
   sideBarWidth: number
   shortcut: string | undefined
-  access_token: string | undefined
+  accessToken: string | undefined
   compressSingletonFolder: boolean
   copyFileButton: boolean
   copySnippetButton: boolean
@@ -18,7 +18,7 @@ export type Config = {
 export enum configKeys {
   sideBarWidth = 'sideBarWidth',
   shortcut = 'shortcut',
-  accessToken = 'access_token',
+  accessToken = 'accessToken',
   compressSingletonFolder = 'compressSingletonFolder',
   copyFileButton = 'copyFileButton',
   copySnippetButton = 'copySnippetButton',
@@ -33,7 +33,7 @@ export enum configKeys {
 const defaultConfigs: Config = {
   sideBarWidth: 260,
   shortcut: undefined,
-  access_token: undefined,
+  accessToken: undefined,
   compressSingletonFolder: true,
   copyFileButton: true,
   copySnippetButton: true,
@@ -55,6 +55,8 @@ function applyDefaultConfigs(configs: Partial<Config>) {
   }, {} as Config)
 }
 
+type VersionedConfig<SiteConfig> = Record<string, SiteConfig> & { configVersion: string }
+
 type Storage = {
   // save root level `configVersion` for easier future migrating
   [key in 'configVersion' | string]: string
@@ -73,7 +75,7 @@ async function migrateConfig() {
     {
       version: '1.0.1',
       async migrate(version) {
-        const config: any | void = await storageHelper.get<Config | Storage>([
+        const config: any | void = await storageHelper.get<Storage>([
           'configVersion',
           'sideBarWidth',
           'shortcut',
@@ -92,7 +94,7 @@ async function migrateConfig() {
     {
       version: '1.3.4',
       async migrate(version) {
-        const config: any | void = await storageHelper.get<Config | Storage>([
+        const config: any | void = await storageHelper.get<VersionedConfig<Config> & Storage>([
           'configVersion',
           'platform_undefined', // this was a mistake :(
           'platform_GitHub',
@@ -112,6 +114,42 @@ async function migrateConfig() {
         }
       },
     },
+    {
+      version: '2.6.0',
+      async migrate(version) {
+        type LegacySiteConfig = {
+          access_token?: string
+        }
+        type MigratedSiteConfig = {
+          accessToken?: string
+        }
+
+        const config = await storageHelper.get<VersionedConfig<LegacySiteConfig> & Storage>()
+        if (config && config.configVersion < version) {
+          const { configVersion, ...restConfig } = config
+          for (const key of Object.keys(restConfig)) {
+            if (
+              typeof restConfig[key] === 'object' &&
+              restConfig[key] &&
+              'access_token' in restConfig[key]
+            ) {
+              const config: LegacySiteConfig = restConfig[key]
+              const { access_token: accessToken, ...legacy } = config
+              const migrated: MigratedSiteConfig = {
+                ...legacy,
+                accessToken,
+              }
+              await storageHelper.set({
+                [key]: migrated,
+              })
+            }
+          }
+          await storageHelper.set({
+            configVersion: version,
+          })
+        }
+      },
+    },
   ]
 
   for (const { version, migrate } of migrations) {
@@ -129,7 +167,7 @@ const prepareConfig = new Promise(async resolve => {
 export async function get(): Promise<Config> {
   await prepareConfig
   const config = await storageHelper.get<Record<string, Config>>([platformStorageKey])
-  return applyDefaultConfigs((config && config[platformStorageKey]) || {})
+  return applyDefaultConfigs(config?.[platformStorageKey] || {})
 }
 
 export async function set(config: Config) {
diff --git a/src/utils/storageHelper.ts b/src/utils/storageHelper.ts
index 5357034..455907a 100644
--- a/src/utils/storageHelper.ts
+++ b/src/utils/storageHelper.ts
@@ -4,7 +4,7 @@ export async function get<
   T extends {
     [key: string]: any
   }
->(mapping: string | string[] | null = null): Promise<T | void> {
+>(mapping: string | string[] | null = null): Promise<T | undefined> {
   try {
     return (await localStorage.get(mapping || undefined)) as T
   } catch (err) {}