How Locket Grew Subscriptions by 77% with Helium

Locket’s origin story

In the summer of 2021, Matt Moss was looking for a way to stay in touch with his girlfriend.

For her birthday, he decided to create a digital “Locket” where they could send each other pictures throughout the day that would show on their iPhone home screens. Quickly afterwards, word spread.

“Even though it was just a private app for the two of us, originally, Ava started showing the app to our friends and they would all ask where they could download it,” he says. “For a while we’d have to turn these people away and say, ‘No, this is just, you know, a private thing’.”

Eventually, though, he was convinced to launch a public app. Since then, the Locket team has raised $12.5 million from OpenAI CEO Sam Altman and Instagram co-founder Mike Krieger.

They’ve also grown to millions of users all over the world, helping their users stay connected to the most important people in their lives.

Locket Gold

In 2024, Locket launched Locket Gold, the Locket Subscription that let users remove ads, customize their widget, and track engagement.

It grew past the team's expectations to many thousands of users globally. The Locket team wanted to accelerate subscription growth, and quickly realized the importance of testing paywalls.

After a few tests, though, they realized how long it was taking and that the paywall testing was distracting them from making the core product better.

They wanted to find a solution that would improve the paywall in their own style, but without all the work of designing, engineering, and experimenting on new paywalls.

Automating paywall testing with Helium

Matt and team were excited about Helium's vision of self-improving paywalls and decided to reach out. Within just a few days, their team had implemented the iOS SDK with RevenueCat and was off to the races.

“Onboarding was 3 a breeze. Once I got the API key it took just a day or two and 15 lines of code and we were live.”

The Helium team worked with Locket to create an experimentation plan, and then started generating the new test paywalls with Helium’s AI Editor, starting by testing a new set of creatives.

Helium started by improving the basics, like plan display, CTA, and exit logic. Then, we generated new heroes drawing on some of Locket Gold's main features.

Speaking to Matt, he highlighted “The Helium team really is great. They’re experts in subscription flows. It’s so nice to know that I can send a slack any time of day and get a response back immediately. It’s awesome to work with a team that moves as fast as we do”

Even after the first experiment, subscription revenue was up substantially. Through paywall improvements, we were able to identify which features spoke most to users, encourage more users to adopt the annual subscription, and improve overall conversion.

“Our first A/B test alone made more than 15-times Helium’s costs, and we’re just getting started. It’s hard to find better ROI than that”

The Helium team did additional testing to identify how to best convert users at each entrypoint and internationally, and have seen an outsized conversion lift for new users.

Since starting with Helium, Locket’s subscription revenue is up 77%

Since that first test, Helium has helped Locket test more than a dozen paywalls, using Helium's personalization systems to identify the best experience for every country, user, and entrypoint.

The testing has helped Locket grow subscription revenue by more than 70%, and we’re just getting started.

“Getting to focus on building new features while my subscription flow gets better all on its own — it’s a dream come true. It’s pretty magical that my paywall just gets better while I sleep.”

With Helium handling paywall optimization behind the scenes, the Locket team can stay focused on what they do best: building joyful, personal ways for people to stay close.