> For the complete documentation index, see [llms.txt](https://help.twinr.dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.twinr.dev/faqs/build-apk-and-ipa.md).
# Build APK & IPA
How to build apk and ipa?
Watch this video
Common things to check before taking build
1. When you have an error, download the error file and try to read it.\
Even if you are not a developer, you might be able to understand the error. So give it a try.
2. Make sure that if you have push notification enabled in Twinr, it must be enabled in your bundle identifier as well under AppStore account.
3. Make sure you click on Publish to production before taking any build.
4. Contact on live chat or via email if you could not understand it.
How much time it takes to complete a build?
For android, it takes around 5 mins.\
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For iOS, it takes 15 mins for the build and then 15 mins to process that build to appear under your TestFlight account.
Do I need to take a new build everytime I do the changes?
No. if you need to change something in your app which is related to UI changes and not dependant on any third party platform, you can do the changes and click on publish to production. You LIVE users will have the changes immediately on the LIVE app.\
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If you have changes like, enabling push notification or changing splash screen, you need to create a new version and publish again.
Build Error: The build with the version “%” can’t be imported because a later version has been closed for new build submissions
**Solution:** Create a new version on AppStore. For example, if the current live version is 1.0.0, create new version 1.0.1 using "+" sign in AppStore. Also, create new version 1.0.1 on Twinr
Build Error: No matching client found for package name 'com.example'
**Solution:** Package name and bundle id in firebase console and in Twinr must match. Please check that you have used the same package name at both places.\
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**Image 1 : Firebase Console**\
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**Image 2 : Twinr Android Package name & iOS bundle id**\
Build Error: Authentication credentials are missing or invalid
**Solution:** Check the Signing info form. There must be one of the field information which is incorrect. Check for extra space as well!\
Build Error: Couldn't find app 'com.example' on the account of '' on App Store Connect
**Solution:** Make sure you have created an app under your AppStore account using the same bundle id that you gave in Twinr. Create new app using "+" button. Make sure you have created bundle id for that app. Request a new build after finishing these steps.
Build Error: Couldn't find bundle identifier '%' for the user
**Solution:** Create a bundle identifier on AppStore using same name as you gave on Twinr. See video:\
Then create an app using that identifier.\
