Locket

How This Developer's Locket App Reached 50 Million Signups Rapidly

March 14th, 2025

Founded By

Matt Moss

Days To Build

Founders

Employees

10 (est.)

Profitable

Yes

Days To Build

Year Started

2022

Customer

B2C

Founded By
Matt Moss: Days To Build
14: Founders
1

Employees
10 (est.): Profitable
Yes: Days To Build
14

Year Started
2022: Customer
B2C

Who is Matt Moss?

Matt Moss is an entrepreneur from San Francisco who graduated in computer science from the University of California, Santa Barbara, and previously started developing apps in middle school and won a scholarship to Apple's Worldwide Developer Conference.

What problem does Locket solve?

Locket solves the problem of staying connected with close friends and family by letting you share real-time photos directly on their home screens, offering a personal touch that's missing from larger social media platforms.

How did Matt come up with the idea for Locket?

Matt Moss came up with the idea for Locket out of a personal need to stay connected with his girlfriend, Ava, as they transitioned to a long-distance relationship. Struck by the idea of a simple yet meaningful way to share photos, he designed a widget as a birthday gift that enabled them to send real-time photos to each other’s homescreens. This personal touch made the app feel more intimate than the broader, more impersonal social networking platforms they regularly used.

Moss noticed how other apps handled communication with wide social networks, often leaving users feeling overwhelmed, whereas Locket was aimed at sharing genuine moments with close friends and family. This realization spurred him to experiment and build on the initial concept, refining the app based on feedback from friends who wanted to use it with their loved ones. As more people expressed interest, Moss decided to make Locket available to the public, validating its appeal beyond his personal circle.

Through this process, Moss learned the importance of focusing on real user needs rather than expansive feature sets, keeping Locket straightforward and personal. He navigated challenges around privacy and functionality with a focus on what would best enhance the user experience, proving that a simple, well-targeted solution can resonate with many.

How did Matt Moss build the initial version of Locket?

Matt Moss developed Locket as a personal side project, initially intended as a gift for his girlfriend. He built the app over a week or two using his background in app development and experience as a former Apple Worldwide Developer Conference student scholarship winner. The app leveraged Apple's iOS widget feature, which was a relatively new concept at the time, to create a virtual photo frame that users could interact with on their home screens. This unique integration allowed users to send photos directly to each other's widgets in real time. The primary challenge in development was ensuring a seamless experience for users, as well as addressing privacy concerns around access to contacts, which Moss planned to refine further. Despite being a small-scale, personal project, Moss successfully scaled the app from a simple prototype to a viral sensation featured on TikTok and beyond, illustrating the often unpredictable nature of app development success.

What were the initial startup costs for Locket?

Funding Rounds: Locket raised $12.5 million in total, with a $10 million round led by Sam Altman, CEO of OpenAI, and a prior $2.5 million friends and family round.

What was the growth strategy for Locket and how did they scale?

TikTok

Locket's explosive growth can largely be attributed to its viral success on TikTok. The founder, Matt Moss, posted a video demonstrating the app, which quickly gained traction with 100,000 views within a few days. This initial visibility encouraged other TikTok users to create their own content about Locket, significantly boosting the app's popularity. One user-generated video in the U.K. achieved 5 million views in a single day.

Why it worked: TikTok is a powerful platform for organic reach, especially among younger audiences. By leveraging a platform where visual content thrives, Locket was able to reach a large, engaged audience quickly. The app's unique offering of personal photo sharing via home screen widgets resonated with TikTok's community, who value authentic and relatable content.

After the app was released, early adopters played a key role in its growth by sharing it with their friends and family. Users enjoyed the intimate nature of the app, leading them to naturally recommend it to others. This organic word-of-mouth spread was instrumental in achieving high download numbers without the need for paid advertising.

Why it worked: The app’s simple yet effective premise of staying connected with close contacts created a compelling reason for users to spread the word. This was amplified on personal and social levels, as the more friends and family who participated, the better the user experience became. Such virality is often crucial for apps in the social networking space, where the value increases as more of a user’s personal connections join.

App Store Visibility

Locket's viral success on TikTok translated to significant visibility on the App Store, landing it in the No. 1 spot on the U.S. App Store's free app charts. This top placement not only boosted its downloads further but also lent credibility and trustworthiness to potential users browsing for new apps.

Why it worked: Achieving a high rank in the App Store significantly enhances an app’s discoverability, providing a form of social proof. Many potential users are likely to download an app if they see it is topping the charts, assuming it must be of high quality or interest. Additionally, the App Store’s algorithm props up trending apps, creating a positive feedback loop that sustains download momentum.

What's the pricing strategy for Locket?

Locket is a free photo-sharing app that focuses on intimate connections, offering no monetization strategy yet, with plans for future paid features through a subscription model.

What were the biggest lessons learned from building Locket?

Leverage Viral Platforms: Locket's success was largely driven by its viral exposure on TikTok, showing how powerful social media can be for gaining rapid traction without paid marketing.
Keep It Simple: The app's straightforward approach of sending photos to a small circle kept the user experience simple, which helped maintain user satisfaction and engagement.
Focus on Core Users: By designing the app for small, intimate groups, Locket emphasized genuine connections, resonating with users tired of traditional social media's broad reach.
Adapt and Evolve: As the app gained users, the focus shifted to enhancing features based on feedback, such as exploring subscription models and potential messaging features, showing the importance of evolution in response to user needs.
Grow Responsibly: Locket maintained a conservative approach to growth by focusing on user retention and experience first, before monetization, ensuring a strong foundation for future expansion.

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