How to A/B test free trials on iOS

As a mobile developer, you’ve probably been asked by your marketing or app growth team to help run trial duration testing at some point. The problem for iOS apps is Apple only allows one introductory offer per subscription group. That makes it difficult to run A/B tests comparing like 3 days vs. 7 days free trials.

There are workarounds though that let you get the information you need to determine the best strategy for your app. We’ll take a look at some of those workarounds to help you find the sweet spot that maximizes your conversions and your LTV.

The one-intro-offer-per-subscription-group problem

Apple has designed its subscription infrastructure to simplify the user experience, but that means sometimes it’s at odds with the needs of developers who want to experiment. A place where these restrictions come into play is that you can only define one introductory offer per subscription group.

A subscription group is a collection of subscriptions defined in App Store Connect that unlock the same functionality. For example, a premium subscription that has both a monthly price and a yearly price. These two subscription products, when added to the same subscription group, allow the user to purchase either one and get the same functionality. This also allows them to cross-grade their subscription to the other option without losing functionality or accidentally subscribing to both durations. A great feature for users, but this design restricts the kind of testing you can do around free trials.

Let’s say you’ve set up a 7-day free trial for your monthly plan, but you think a 14-day trial might actually work better after collecting some initial conversion data. You can’t assign both trial lengths to products in the same subscription group. And even if you could, once a user accepts (or even sees) an intro offer, they’re locked out from redeeming any others, even if you were to change it later.

This limitation presents a real challenge to optimizing trial durations through testing. You can’t A/B test different lengths in a clean and native way. You risk burning your only opportunity to show your user an offer using a suboptimal trial length. And it limits your ability to iterate based on real user behavior.

It can be quite frustrating for teams focused on conversion optimization. Thankfully there are some ways around it. Let’s see what we can do next.

Creating multiple subscription groups

A way to allow for testing of trial lengths while remaining inside the confines of Apple’s infrastructure is to create multiple subscription groups in App Store Connect, each with a different introductory trial.

You could create a group with a subscription product that has a 3-day trial for example. Then you’d create a second group with a similar product that instead has a 7-day trial. The obvious advantage is that you can use these two subscription options to run an A/B test to see which converts better with your audience.

The easiest way to do this would be to use Adapty’s Paywall Builder to design two paywalls that show each subscription separately but are otherwise the same. Paywall Builder allows you to quickly design a paywall and then duplicate it to build the other variant, keeping everything the same except which product is offered.

Then you can set up an A/B test pitting those two paywalls against each other. You can make a data-driven decision about which trial length is best and even promote the winning paywall to be used for everyone after the test is complete.

Using two subscription groups and Adapty’s paywall and A/B testing lets you effectively test trial durations while staying within Apple’s rules.

It’s not a perfect solution, however. You want to keep in mind these downsides:

• Users can’t switch between groups. Once assigned they’re locked into that group.
• You need to manage the subscription groups independently in App Store Connect.
• Because the subscriptions exist in different groups, a user can subscribe to both concurrently. This will require some extra diligence on your part to not present both to the same user to prevent over-subscribing.

Despite the added setup and complexity, this approach is powerful because it preserves the “Free Trial” label in the App Store purchase screen, which users are trained to look for and is a key factor in conversion rates.

Running country-based free trial testing

Another option is to leverage the fact that Apple allows you to assign introductory offers on a per-country basis to test what might convert better.

The advantages to this approach are that you don’t have to create or manage multiple subscription groups, and that it’s pretty simple to configure in App Store Connect.

The downside is you will need to compare trial start and conversion data between the regions you’ve set up and differences in behavior could skew the results.

This is not a pure A/B test so it will be hard to isolate the trial length as the only variable. For example, you may need to adjust the copy and design on your paywalls a bit to fit local cultural norms for each region.

To set this up, you could do something like the following:

• A 3-day trial for users in the U.S.
• A 7-day trial for users in Canada.
• No trial at all in another region if you want a control group.

Then you could compare behavior across those regions in a tool like Adapty’s analytics dashboard to see which trial lengths drive better conversion, retention, and long-term revenue.

This approach works especially well when you’re early in the experimentation phase and want to determine what’s directionally correct for your conversion strategy. If you see clear differences between regions, it’s a clue to look deeper at how you’ve presented each and refine the test.

Setting up custom trials outside Apple’s intro offers

If you want to be free of the limitations that Apple sets, you do have the option of “rolling your own” free trial logic that’s outside of Apple’s introductory offer system. This affords you the flexibility you might want, but it’s also the most technically intense workaround.

Instead of relying on the App Store to manage the trial, you would opt users into a free trial with a custom button from an Adapty paywall that actually triggers a call to the Adapty servers to grant access to premium features for a set amount of time. This effectively sets up a “free trial” of the premium features, but bypasses actually making a purchase or automatically opting the user into converting to paid at the end of the trial. You would have to show them a traditional paywall at the end of the trial with subscription products for them to choose from.

This approach lets you test any trial duration you want since you’re controlling access to premium features directly for an arbitrary amount of time. You also don’t have to worry about the overhead of multiple subscription groups and you can run real A/B tests with Adapty’s tools to make a data-driven decision about what converts better.

This may sound like the perfect solution, but there are a few things to consider first. There won’t be a free trial label anywhere on the App Store checkout screen or the store listing. Users are trained to look for this and it may be a bit of a deterrent. It’s also more technical work and overhead on your part to manage these internal free trials. And since this management logic is on you rather than Apple, you’ll have to code it carefully to reasonably guard against abuse.

It is a fair amount of initial work to get going, but paired with the Adapty in-app purchase SDK and the A/B testing and analytics features in the Adapty dashboard, you’ll end up with a setup that gives you unmatched flexibility for experimentation with free trials.

What does the data really tell you?

Once you’ve run your experiments long enough to generate statistically significant data (made much shorter by using Adapty’s AI-powered A/B test winner prediction), it’s time to use this data to figure out what’s working.

Start by evaluating the trial groups against key metrics like: which trial length led to the highest trial-to-paid conversion; whether shorter trial lengths created urgency, or maybe just higher churn; and which trial length led to users with higher LTV or longer retention.

You can use the above data with Adapty’s cohort analysis feature to also see how long these people stuck around and how much revenue they generated over time.

As you analyze your results, here are some things to keep in mind to prevent the data from leading you down the wrong path:

• Don’t rely solely on short-term conversion rates. Sometimes longer free trials convert fewer people, but those users produce a higher LTV.
• If you have high conversion but high churn, take a look at: revenue per user in addition to conversion rate, churn in the first 1-2 billing cycles, and engagement of those users during the trial to make sure they are actually experiencing the value you’re providing.
• Sample size can really skew your conclusions when comparing variants, so make sure your sample sizes are large enough. If not, consider extending the length of your test or re-run it with larger cohorts.

Lastly, the best-performing trial might surprise you so be sure to try options that don’t necessarily seem to be obvious winners. Testing and iteration are critical for success in this process.

At Adapty, we help app teams with tools built specifically for subscription businesses. From remote config and paywall A/B tests to real-time revenue analytics and cohort tracking, we give you everything you need to test, learn, and grow.

Ready to optimize your trial strategy? Start using Adapty today and take control of your app’s monetization roadmap.