LINE & Yahoo Japan Premium (LYP Premium)
What I did
I led the feature from concept to launch, contributing across design and product strategy. By grounding decisions in user research and data, the feature became a key driver of LYP Premium subscription growth.
My role
Product Designer, Product Manager
Platform
iOS, Android
Timeline
Skills
Data analysis, UX strategy,
Product management, Wireframing, User research & testing
Team
2 UI Designers
2 Graphic Designers
4 Engineers
What's LYP Premium?
A membership service for LINE, Yahoo Japan, and PayPay.
LYP Premium is a membership services offering 20+ exclusive benefits across LINE, Yahoo Japan, and PayPay. These services cover everything from web portals and messaging to payments, reaching nearly the entire Japanese population.
Context
Slowdown in new premium subscriptions
About a year after launching LYP Premium, and following the end of the last marketing campaign, new premium subscriptions through LINE Messenger began to decline rapidly.
Low retention among Gen Z users
Although Gen Z users accounted for nearly half of all premium subscribers, 58% canceled their subscription after the 3-month free trial.
Project goal
How might we help Gen Z LINE users recognize the value of Premium Membership and ultimately drive higher subscription retention?
Conversion rate
56% decrease
Within a week of the launch, the number of new premium membership subscriptions increased to 605 users, a 228% increase from the previous week.
Usage rate per visit
69.4%
69.4% of users who visited the Custom App Icon screen changed their icon design.
Total subscription
35.3% increase
Of the 34K new subscribers, 12K registered through the custom app icon, representing 35.3% of the total.
Timeline
Market opportunities
Strong demand for customization among Gen Z premium users
Sticker and font customization are among the most-used features, with Gen Z making up about 42% of their user base.
Positive response to LINE’s customization effects
Over 80% of women across all age groups and men aged 15-19 responded positively to various effects in the Home Tab and Chat Room.
Custom app icon features in other services
Offering some free icons with additional paid options shows higher usability and engagement.
Concept validation
Tested the concept with Gen Z users through rapid prototypes
Overview
Method: Online survey
Participants: 3000 LINE users (Gen Z, ages 15-24)
Collaboration: UX Research team
Expectations
Users expect exclusive premium icons to be monthly updated
The largest group (about 25%) said they’d like to change their app icon once a month and expected monthly icon updates to stay subscribed.
Users want to change icons directly within the app
32% of LINE users were already using third-party apps to customize their icons. They preferred changing icons directly within the app, rather than relying on external tools.
Based on these insights, we decided to update premium icons monthly and allow users to change icons easily within the app.
App icon design survey
Based on 48 icon concepts created by our graphic team, I ran an online survey to understand user preferences.
With a tight two-month timeline, I ran an internal survey using Japan HQ employees in their 20s to quickly validate Gen Z icon preferences and guide design decisions.
Findings
Informed by the survey results, I finalized the initial icon set with seasonal, playful designs that resonated most with Gen Z users.
Solution
Easy access to change the app icon
Based on user research, I made this feature easily accessible by adding an app icon screen in LINE’s settings menu, allowing users to change the icon effortlessly without an additional customization app.
Different screens based on
premium membership status
To reach a wider audience, we made this feature available to all users, reserving exclusive icons for premium members to highlight the benefits of subscribing.
Basic icons
Basic icons are available to all users, regardless of premium membership status
Premium icons
Premium icons are exclusively for premium subscribers and new icons designs are added each month.
Screen for non-subscribers
Non-subscribers have access to free Basic icons only, while Premium icons are marked with a badge to indicate they’re exclusive to Premium members. If a user selects a Premium icon, they’re directed to the subscription screen.
Screen for premium subscribers
Subscribers can access all icons, with new premium designs added each month.
Auto-updated promotional icon
Free premium icons available to all users for a limited time
To make the new feature more visible, I proposed an auto-updated promotional icon. During seasonal moments like Halloween and Christmas, users’ app icons are automatically updated, allowing everyone to try premium icons for a limited time and discover the feature naturally.
Auto-Apply button for promotions
I designed an auto-apply toggle at the top of the screen and turned it on by default, so users could enjoy the promotional icon immediately at launch.
Promotional icon indicator
Promotional icons were marked with a star icon so users could easily spot the difference.
Matching themed LINE profile
To enhance the visual impact, we matched the LINE main page profile design with the same seasonal theme.
Splash image set with the icon
To maximize the impact of the custom app icons, we also provided splash images that match the icon colors. When users changed the icon, the corresponding splash image was displayed to ensure they noticed the change.
Cross-platform design
I adapted the design for portrait light and dark modes, landscape, and iPad, ensuring it fits each platform’s requirements.
Press release
Over 18 press releases were published within a week following the release.
Takeaway
This project gave me a broader view of product development, going beyond UI design to shaping product direction through data-driven decisions.
What I enjoyed most about this project was wearing multiple hats, not only designing the UI but also contributing to the overall product direction. By leading a data-driven process grounded in user research, I helped the team move beyond top-down decisions and make more informed, user-centered choices.
© Soyun Moon 2026
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