App Configuration

Open Settings with the icon in the main menu, choose General, then pick one of the tabs after Basic.

Your Expo app’s configuration lives in app.config.js (or app.config.ts) at the root of your app. It holds what the app stores and devices see: the app’s name, version and build number, icon, splash screen, bundle identifier, package name, permissions, plugins, and more. Preview builds, one-click publishing, and code export all read it. The tabs in Settings edit this file for you, so you don’t have to touch the code. They’re only shown for Expo apps.

This page lists every field. For how changes save, commit, and reset, and for the App Config Agent, see Settings.

Tip

Want full control? Each tab ends with Open in Code Editor, which opens the file in Code Editing mode. Code Editing requires the Standard plan or above.

How the tabs are organized

Each tab has its everyday fields first. Some tabs group related fields in their own card, like Plugins or Permissions. Then come up to two collapsed sections:

• Advanced: rarely changed fields, and fields that Draftbit Publishing sets for you. Those show “This value may be overridden during Draftbit Publishing” under the input.
• Dangerous: changing these properties may break your ability to preview the app in Draftbit. Leave them at their defaults unless you have a specific reason to change them.

Fields marked with a red asterisk are required. If a value doesn’t pass a check (for example, a version that isn’t in 1.0.0 format), the field shows an error and you can’t commit until you fix it.

Fields marked (dynamic)

Not every value in app.config.js is a plain value. If a field is set by code, such as process.env.APP_NAME or a function call, its label shows (dynamic) and you’ll see the JavaScript instead of the usual input, with the note “This value contains dynamic code and must be edited as JavaScript”. Your edit is saved as code, so a plain value needs quotes, like "1.0.0". If the code isn’t a valid JavaScript expression, the change isn’t saved and you’ll see Save failed until you fix it. For bigger changes to dynamic values, use Open in Code Editor or ask the App Config Agent.

Versions and build numbers

Each store submission needs a higher build number than the last one, so this is the part of the configuration you’ll touch most.

Field	Where	What it is
Version	General, Advanced	The version people see in the app stores, in 1.0.0 format. Written to version.
Build Number	iOS, Advanced	The internal iOS build number, a whole number. Written to ios.buildNumber.
Version Code	Android, Advanced	The internal Android version number, a whole number. Written to android.versionCode.

When you publish with one-click publishing, the publish dialog suggests the next version for you. It starts from your most recent publish to that platform and adds one to the last part of Version Name (1.0.3 becomes 1.0.4) and one to Version Number. You can change either value before you start the publish.

When the publish starts, Draftbit writes Version Name to Version and Version Number to both Build Number and Version Code, along with the bundle identifier or package name from your publishing settings. It then commits the updated file to your app. That’s why these fields say “This value may be overridden during Draftbit Publishing”.

Setting a specific build number

To publish a particular version or build number, for example to get above a build you uploaded to TestFlight or Google Play yourself, enter it in the publish dialog. A value you only change in Settings is replaced by the dialog’s value at the next publish.

General

Field	Description
App Name	The name of your app as it appears on the home screen when installed. Required, up to 50 characters.
Description	A short description of what your app is and why it is great. Up to 1,000 characters.
Slug	A URL-friendly identifier for your app, used in publishing and build processes. Required. Lowercase letters, numbers, and single hyphens only, starting with a letter or number.
URL Scheme	URL scheme for deep linking into your app (for example, myapp:// would use myapp). Must start with a letter.
Orientation	Lock your app to portrait or landscape, or choose default to allow rotation.
Interface Style	Force light or dark mode, or choose automatic to follow the device setting.

Plugins

Plugins lists the Expo config plugins your app uses, as JSON. Config plugins make native changes at build time. Many packages with native code, including iOS extensions, need one before they work in a published build. Each entry is either a package name, like "expo-camera", or a [name, options] pair:

["expo-font", ["expo-camera", { "cameraPermission": "Allow $(PRODUCT_NAME) to use your camera." }]]

Your edits only take effect while the box holds valid JSON. If a feature works in preview but not in a published build, check that its package’s plugin is in this list.

Advanced

Field	Description
Version	See Versions and build numbers.
Locales	Localization settings, as JSON. Keys are locale codes (for example, en or ja) and values are paths to JSON files.
Asset Bundle Patterns	Glob patterns for assets to include in the bundle, as JSON. For example, ["**/*"] includes all assets.
Extra	Custom data, as JSON, that your app can read at runtime through Constants.expoConfig.extra. Don’t put secrets here, since it ships inside your app.

Dangerous

Field	Description
Platforms	The platforms your app supports: ios, android, and web. Expo uses this to decide which native projects to generate.
JavaScript Engine	hermes (recommended, for better performance and a smaller bundle) or jsc.

Icon

Field	Description
App Icon	The icon people see on their home screen. Pick an image from your app, upload one to its assets folder, or enter a path or URL. Use a square 1024×1024 PNG.
Use Project Icon	Use the icon set for the whole project in Settings › Project Settings. Only shown when the project has an icon.

View icon configuration on Expo Docs →

Splash Screen

The splash screen shows briefly while your app loads.

Field	Description
Splash Image	Local path or remote URL to an image for the splash screen. Use a 1284×2778 PNG for best results.
Background Color	Background color for the splash screen, as a hex color like #ffffff.
Resize Mode	How the splash image fits the screen: contain, cover, or native.

View splash screen configuration on Expo Docs →

Notifications

These settings control how push notifications look. To set up push notifications end to end, see the iOS and Android guides.

Field	Description
Notification Icon	Local path or URL to an image for the Android notification icon. Must be a 96×96 PNG with transparency.
Notification Color	Tint color for the notification icon on Android.
iOS Display in Foreground	Show notifications when the app is in the foreground on iOS.
Android Mode	How notifications are displayed on Android: default or collapse.
Android Collapsed Title	Title shown when multiple notifications are collapsed on Android.

View notifications configuration on Expo Docs →

iOS

Field	Description
Bundle Identifier	Unique identifier for your iOS app, in reverse domain format (for example, com.company.appname). Required for the App Store. Learn more →
Supports Tablet	Whether your app supports iPad.
Uses Apple Sign In	Enable the Sign in with Apple capability for your app. Learn more →
Require Full Screen	Require the app to run full screen on iPad, which turns off Split View and Slide Over.
Associated Domains	Domains for Universal Links and other app-to-web connections, as JSON. For example, ["applinks:example.com"]. Learn more →
App Store URL	URL to your app on the App Store, used for rate prompts and sharing.
Uses Non-Exempt Encryption	Your export compliance answer for App Store Connect. Choose False if your app only uses standard encryption such as HTTPS, and TestFlight builds skip the encryption question. Choose True if your app uses proprietary or non-standard cryptography. Leave both unselected to answer in App Store Connect for each build. Learn more →

View iOS configuration reference on Expo Docs →

Permissions

iOS requires a reason for each permission your app asks for. The reason is the text iOS shows in the permission prompt. The prompt itself appears only when your app’s code requests access, usually through the Expo package for that feature, which the agent adds when it builds the feature. Leave the field empty for permissions you don’t need. Each field is written to the matching key under ios.infoPlist.

Apple’s App Review reads these too, so say plainly what your app does with the access.

Field	Info.plist key	Example reason
Camera	NSCameraUsageDescription	This app needs camera access to take photos and scan barcodes
Microphone	NSMicrophoneUsageDescription	This app needs microphone access to record audio
Photo Library (Read)	NSPhotoLibraryUsageDescription	This app needs access to your photos to let you select images
Photo Library (Write)	NSPhotoLibraryAddUsageDescription	This app needs permission to save photos to your library
Location (When In Use)	NSLocationWhenInUseUsageDescription	This app needs your location to show nearby places
Location (Always)	NSLocationAlwaysUsageDescription	This app needs background location access to track your route
Contacts	NSContactsUsageDescription	This app needs access to your contacts to help you connect with friends
Calendar	NSCalendarsUsageDescription	This app needs calendar access to create and manage events
Reminders	NSRemindersUsageDescription	This app needs access to your reminders to sync tasks
Motion & Fitness	NSMotionUsageDescription	This app needs motion data to track your steps and activity
Face ID	NSFaceIDUsageDescription	This app uses Face ID for secure authentication
Speech Recognition	NSSpeechRecognitionUsageDescription	This app needs speech recognition to convert your voice to text
Bluetooth	NSBluetoothPeripheralUsageDescription	This app needs Bluetooth to connect to nearby devices
Apple Music	NSAppleMusicUsageDescription	This app needs access to Apple Music to play songs from your library
User Tracking (ATT)	NSUserTrackingUsageDescription	This app uses tracking to provide personalized ads

User Tracking (ATT) is required if your app tracks users for advertising. The reason sets the text of the App Tracking Transparency prompt, but the prompt appears only when your app requests it, for example with requestTrackingPermissionsAsync() from expo-tracking-transparency. If your app doesn’t request it yet, ask the agent to add the request. Apple can reject apps that track users without asking.

View iOS permissions guide →

Advanced

Field	Description
Build Number	See Versions and build numbers.
Tablet Only	Run the app only on iPad, not iPhone.
Privacy Manifests	Declares, as JSON, which Apple APIs your app uses and why. Required for App Store submissions. We recommend asking the App Config Agent to fill this in. Learn more →

Dangerous

Field	Description
Bitcode	Enable Bitcode for iOS builds. Apple has deprecated Bitcode, and newer Expo SDKs turn it off by default.

Android

Field	Description
Package Name	Unique identifier for your Android app, in lowercase reverse domain format (for example, com.company.appname). Required for the Play Store. Learn more →
Adaptive Icon Foreground	Foreground image for Android adaptive icons. Use a 1024×1024 PNG with transparency. Learn more →
Adaptive Icon Background	Background color for Android adaptive icons.

View Android configuration reference on Expo Docs →

Permissions

Field	Description
Permissions	Android permissions to include in your app. They’re added to AndroidManifest.xml.
Blocked Permissions	Android permissions to explicitly remove. Use this to block permissions that libraries add.

Both fields offer these permissions:

• ACCESS_BACKGROUND_LOCATION
• ACCESS_COARSE_LOCATION
• ACCESS_FINE_LOCATION
• BLUETOOTH_CONNECT
• BLUETOOTH_SCAN
• CALL_PHONE
• CAMERA
• FOREGROUND_SERVICE
• POST_NOTIFICATIONS
• READ_CALENDAR
• READ_CONTACTS
• READ_EXTERNAL_STORAGE
• READ_MEDIA_AUDIO
• READ_MEDIA_IMAGES
• READ_MEDIA_VIDEO
• READ_PHONE_STATE
• RECEIVE_BOOT_COMPLETED
• RECEIVE_SMS
• RECORD_AUDIO
• SEND_SMS
• USE_BIOMETRIC
• VIBRATE
• WRITE_CALENDAR
• WRITE_CONTACTS
• WRITE_EXTERNAL_STORAGE

View Android permissions reference →

Advanced

Field	Description
Version Code	See Versions and build numbers.
Allow Backup	Allow the app’s data to be backed up to Google Drive. Turn off for apps with sensitive data.

Web

When you publish your app to the web, it can work like a Progressive Web App (PWA) that people can install on their devices. These settings control how your web app looks in browsers and when installed.

Field	Description
Favicon	Local path or URL to an image for the web favicon. Recommended: 48×48 PNG. Learn more →
Theme Color	Theme color for the web app, used in the browser toolbar and PWA splash screen. Learn more →
Name	Full name of the web app, shown in the browser tab and PWA install prompt. Learn more →
Short Name	Short name for the PWA (about 12 characters at most), shown on the home screen when installed. Learn more →
Language	Language code for the web app (for example, en, en-US, or ja). Learn more →
Background Color	Background color for the PWA splash screen and while the app loads. Learn more →
Description	Description for the PWA manifest, shown in browser install prompts. Learn more →
Orientation	Default orientation for the web app when installed as a PWA. Learn more →
Start URL	URL that loads when the PWA is launched from the home screen. Defaults to /. Learn more →

Note

Not all properties work in every browser. See the Expo reference below for browser compatibility.

Dangerous

Field	Description
Output	Output format for web builds: single for a single-page app, static for static site generation, or server for server-side rendering.
Bundler	Bundler for web builds: metro (recommended) or webpack.

View Web configuration reference on Expo Docs →