Project Overview
Mojey is a groundbreaking exploration into digital transactions. It aims to replicate the directness of cash exchanges without traditional databases, servers, or blockchain technologies. This case study follows the journey from concept to reality, highlighting the challenges, insights, and solutions discovered through rigorous user experience research and development.
Project duration: 2 Months
My role
UX Lead
My Responsibilities
Research, wire framing, design, prototyping
The Problem
Despite the declining use of cash in society, there remains an essential need for direct, physical transactions between individuals in communities.
The Goal
At Block.one, while we develop blockchains, we recognize the need for off-blockchain transactions. Similar to a cash drawer, users may want to exchange crypto value off-chain by sharing keys. This works when community members are trustworthy and don't keep copies of keys to assets they've traded. We aim to enable verifiable key exchanges within communities and ensure deletion from devices—creating a digital "cash drawer." The first step is ensuring users have the right denominations of exchangeable currency.
Understanding the user
- User research
- Personas
- Problem statements
Research Phase: Rediscovering the Essence of Cash Transactions
Initial Exploration and Concept Validation
We began by studying the fundamentals of cash transactions. In today's growing digital economy, we faced a key challenge: how to recreate the simplicity of cash exchanges in digital form. Our research phase started with whiteboard sessions to map out transaction flows and understand both the mechanics and human elements of cash usage.
User research
User research: Summary
To gain a deeper understanding of user needs, I interviewed individuals in the office and at local stores and restaurants where they used cash registers.
User research pain points
1 | Physical Money is dirty | “I worked in a bank, and when we receive cash it’s so much more real.” |
2 | Running out | “I often run out of 1’s and 5s, so double those denominations when I start a shift.” |
3 | Cultural | “I use cash and watch my spending. Most kids here in college have no idea what they are spending - because it’s all digital.” |
4 | Accessibility | “All US$ bills are the same size, so I say-and-show older people what they gave be before making change.” |
Personas
Persona 1 | Former Bank Employee |
Age:46,Education:MBA,Home town:Charlotte, NC,Family:Married w/ 2 children,Occupation:Finance | |
Problem statement | Jane, a former bank employee, has developed an aversion to handling physical cash due to hygiene concerns. This discomfort creates challenges in situations where cash is required. She's open to digital payment solutions that retain the immediacy and personal nature of cash transactions while feeling more "human." |
"I worked in a bank, and when we receive cash it's so much more real." |
Persona 2 | Coffee Shop Cashier |
Age:19,Education:High school,Home town:Radford, VA,Family:Single,Occupation:Full-time coffee shop worker | |
Problem statement | Victor, a coffee shop cashier, struggles with efficient cash handling, leading to customer dissatisfaction and longer lines. Though these challenges affect his workflow, he notices that cash-paying customers tend to tip more generously. He's open to using an app that captures the familiar feel of cash transactions. |
"I often run out of 1's and 5s, so it can be a challenge." |
Persona 3 | Engineering Student at Farmers Market |
Age:19,Education:In College,Home town:Blacksburg, VA,Family:Single,Occupation:Engineering Student | |
Problem statement | John, an engineering student who shops at the college farmers market, prefers using cash to track his spending. In today's digital economy, he finds it difficult to maintain the same clear oversight of his expenses that cash provides. He needs a digital solution that offers the same transparent spending awareness he gets with physical money. |
"I use cash and watch my spending. Most kids here in college have no idea what they are spending—because it's all digital." |
Persona 4 | Visually Impaired Individual Seeking Payment Verification |
Age:36,Education:High school,Home town:Tustin, CA,Family:Single,Occupation:Retired (disabled) | |
Problem statement | James, who is visually impaired, relies on tactile feedback to verify payments while shopping. While he prefers cash for its distinctive textures, he's open to digital alternatives. James needs a system that combines the directness of cash transactions with clear audio confirmation of payment details. |
"All US$ bills are the same size, but I can identify them by touch. With digital payments, I have to trust the vendor and verify my account later." |
Field Research: Immersion and Observation
To gain real-world insights, our team observed cash transactions firsthand at local shops and farmers' markets. This immersion phase proved crucial for understanding the nuances of cash exchanges and evaluating how effectively we could replicate this experience in digital form.
We asked cash register users about their experiences.
Feedback fell into two distinct categories:
- Professionals who use cash drawers daily were comfortable handling both cash and credit transactions.
- Part-time student workers used cash only at work and preferred credit cards for their simplicity.
Prototyping Phase: Bridging the Digital Divide
Developing the Initial Prototype
Inspired by our research findings, we developed a digital cash application prototype modeled after The Cash app (shown below). Our goal was to replicate the physical act of exchanging denominated currency. This prototype became an essential tool for validating our concept and testing its viability with potential users.
User Testing and Feedback
We conducted extensive user testing across diverse groups within our organization, offering Starbucks cards as incentives to participants.
The kinds of questions we asked:
- The total is $12.50. Your customer hands you $15.00. Please select the amount of change and press "Send".
- The total is $39.40. Your customer hands you two $20 bills. What do you do?
During testing with participants from different departments, the responses to using cash were consistent:
"This is going backward—to 20 years ago."
"We don't need large denominations—just dollars and pennies. They don't take up space like real bills."
Calculator alternative to prototype
When we asked users to calculate the answer to scenario #2 using their phone's calculator, they provided valuable insights:
"The customer gets to see the number before completing the change return."
"This makes more sense. I prefer not using denominations."
Despite our solution's innovative approach, the feedback highlighted a clear disconnect. Users questioned the logic of returning to a denomination-based model in a digital format, challenging both its necessity and practicality.
Critical Learning
Cash is physical and personal. We Do NOT keep track of it on a digital ledger. We need a digital equivalent.
Refinement Phase: Addressing Core User Needs
Rethinking Our Approach
User feedback marked a crucial turning point that led us to reevaluate our objectives. We realized that our challenge went beyond simply digitalizing cash transactions—we needed to simplify the entire process while enhancing security. This insight guided us toward developing a solution that would make transactions effortless while building trust through familiar elements.
Introducing Emoji as a Transaction Medium
This fresh perspective inspired us to use emojis as our value exchange medium. Since emojis are already part of everyday digital communication, they offered the perfect foundation for creating an intuitive and engaging transaction experience.
Mobile
Prototype
User testing formed the foundation of our development process. We created prototypes based on extensive research, drawing inspiration from The Cash app to replicate physical currency exchanges. These prototypes served as essential tools for validating our concept with potential users.
We conducted thorough testing with diverse groups across the organization, offering Starbucks cards as participant incentives. Participants completed various cash transaction scenarios and tasks to help evaluate the system's effectiveness.
The feedback we received proved invaluable in steering the project's direction. It revealed the need for a solution that went beyond simple transactions—users wanted both convenience and trustworthiness. This insight led us to embrace emojis as our value exchange medium, leveraging their universal recognition and everyday familiarity.
Implementation Phase: Seamless Integration and Usability
Building Within a Familiar Ecosystem
We integrated our solution into Apple's Messages app, taking advantage of its widespread use to create a seamless and accessible experience. This strategic choice allowed us to build on users' existing behaviors rather than requiring them to adopt a new platform.
Iterative Design for Enhanced Usability
Our design philosophy prioritized simplicity and intuition. Through careful testing and refinement, we created a streamlined transaction process that felt as natural as sending a message, with minimal steps and maximum ease of use.
Prototype testing
Finalization Phase: Beyond a Transactional Tool
From Prototype to Product
Adhering to Apple's Human-Computer Interaction (HCI) guidelines and employing Swift for development, we transformed our prototype into a fully functional app. This process underscored the importance of aligning with established design standards and leveraging efficient programming languages to expedite product development.
Watch
Extending the Application's Reach
Our commitment to creating a versatile and user-centric solution was further demonstrated through the development of a Watch extension app. This extension highlighted the app's practicality and wide accessibility across different devices.
Prototypes
Buy Mojey
Send Mojey
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Screens
Conclusion: A New Horizon in Digital Transactions
Business and Community Impact
The development and launch of Mojey represented a significant milestone in digital transaction technology. When the COVID-19 pandemic emerged, we pivoted to release the project as open source, sharing valuable insights and tools with the wider community.
Reflections and Future Directions
This case study demonstrates how user-centric research, prototyping, and iterative design drive innovation. Through active user feedback, challenging assumptions, and building on familiar digital behaviors, Mojey has created a blueprint for advancing digital transactions—one that prioritizes simplicity, security, and meaningful user engagement.
©2025 Thomas Hallgren