You can test an unreleased iOS mobile app via TestFlight. TestFlight offers a feature called “TestFlight Public Link” where you can invite up to 10,000 testers with a public invitation link.
Generating a TestFlight link
Step 1. Log into App Store Connect
Step 2. In the header, click TestFlight
Step 3. Create an External Group by clicking the + button (if you already have an External Group, head to Step 5)
Step 4. Name your group
Step 5. Scroll down to the Build section and click "Add Build"
Step 6. Select & submit your build. You will have to wait for the App Store to approve the build.
Step 7. Once the build is approved, generate a link. Head to the Tester Management section. Select “Enable Public Link”.
Once the link is enabled, you will see it listed under Public Link.
Step 8. Head back to PlaybookUX and paste the link as a URL.
When you insert your TestFlight URL, the PlaybookUX app will automatically register that the study is a TestFlight study. It will provide testers special TestFlight instructions.
Since TestFlight only works for testers taking the study on an iPhone, you'll need to ensure that testers take the study on an iPhone. The best way to do that is to include a screener question:
Example Screener Question
The testers will see TestFlight specific instructions while taking the study. Here's what the testers will see:
Once the tester clicks the button "Download TestFlight" they will be asked to download the TestFlight app & the test app.
Once they download the TestFlight app & the test app, the tester will be able to proceed to questions.
Testers won't be able to click the "Proceed to questions" button until they select the "Download TestFlight" button.
During the study the tester is instructed to switch between the PlaybookUX app (which contains the tasks) and your app.