Knock-troc
A barter-based sharing platform for everyday needs
CONTEXT
Knock-troc is a non-monetary exchange platform designed to connect people through goods, services, and skills.
Inspired by my experience of living in France, I observed a gap between underutilized resources and costly everyday services.
Through this project, I explore how design can shift exchange from transactional to relational — building a system based on trust, reciprocity, and human connection.
BACKGROUND
After moving from China to France, I noticed a significant shift in the cost structure of daily life: While goods were relatively affordable, but human services such as moving, printing, or small tasks were surprisingly expensive.
For students and low-income groups, this created a dilemma: even basic help required money. Meanwhile, many people had underutilized resources — spare time, unused items, or skills.
PROBLEM DEFINITION
How might we enable people to exchange without relying on money, while improving resource efficiency and reducing waste?
Over-reliance on Monetary Transactions
Everyday needs depend heavily on money, limiting accessibility for low-income users.
Underutilized Resources
Time, skills, and goods remain unused due to a lack of effective matching systems.
Unsustainable Consumption
Without alternatives, people default to buying instead of reusing existing resources.
DATA MINING*
Grounding design decisions in real-world data and behavioral insights
85%+
with high digital adoption, mobile platforms provide a strong foundation
60%
have engaged in second-hand consumption
50%
of household spending goes to services
~30%
of users engage in sharing economy platforms
Despite these trends, most exchanges remain monetary-based, leaving time, skills, and goods underutilized
*Data sourced from INSEE, Eurostat, and ADEME reports (2017–2018)
SOLUTION
Knock Troc is a mobile platform that enables users to exchange goods and services directly, without monetary transactions
Item ↔ Item
Service ↔ Item
Skill ↔ Skill
A mobile app that allows people to exchange items freely is an excellent solution; this app should include the following 4 core features :
Smart matching
Connects users with complementary needs and resources to enable efficient exchanges.
Direct Communication
Enables users to negotiate and coordinate exchanges in a simple, human way.
Offer & Request System
Allows users to easily post what they can offer or what they need.
Trust & Reputation
Builds credibility through ratings and exchange history to reduce uncertainty.
HYPOTHESIS
If users are given a trusted platform for non-monetary exchange, they will be more willing to exchange goods and services without money, as it addresses their needs for efficiency, trust, and social connection.
THEORETICAL RESEARCH
To explore the feasibility and business model of this app, I conducted extensive research and wrote a paper focusing on the current trends in the sharing economy and the green economy. If you’re interested, you can download the paper to learn more.
DESIGN PROCESS
From insights to solutions through a structured design approach.
01
Research
Understand user behavior, market context, and key problems through data and analysis.
02
User flow
Map out user journeys to define clear and efficient interaction paths.
03
UX Design
Structure the experience by organizing inform-ation and defining core interactions.
04
Wireframe
Translate concepts into low-fidelity layouts to explore structure and usability.
05
Design creation
Develop the final visual design to deliver a cohesive and engaging user experience.
VOILÀ! KNOC-TROC
VISUAL CONCEPT
A cohesive visual system including logo, typography, color, and icons
Logo and Visual
The visual identity was designed to introduce a sense of playfulness and emotional engagement, reframing exchange as an experience of discovery rather than transaction.
Inspired by this idea, I introduced Jack — a magician-like character who acts as both a mascot and a guide. His quirky personality reflects the platform’s intention: to make value exchange feel intuitive, human, and full of unexpected possibilities.
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Typeface and color pattern
Roboto-Regular
a b c d e f g h i j k l m n o p q r s t u v w x y z
1 2 3 4 5 6 7 8 9 0
This font is used in the logo, certain special components, and illustrations.
This font is used in interface design, including the main UI design and video components.
#339CD1
#3F7652
#682B18
#D15247
#E2C4AD
#F8E8D8
#000000
#252626
#3E3A39
#545656
#9AA3A8
Icons
for example, the single-color ones are used as decorative patterns, while the colored ones are used in interface design, videos, and related designs.
These icons are used in various contexts throughout the project
EMOJI&ILLUSTRATION
I created a series of illustrations and expressive elements based on the app’s mascot, the magician, to enrich the visual identity and enhance emotional engagement
Concept
These playful visuals help make the experience more approachable and enjoyable, reinforcing a sense of friendliness and human connection throughout the app
LET'S SEE
RABBIT
GUESS WHAT?
HERE WE GO
STOP
NICE
SORRY
LOOK THIS
0,5 x
0,7 x
1 x
1 x
Designed with consistent proportions, the mascot creates a playful yet unified visual language
MOBILEAPP ICON
USER STUDY
I conducted quick user testing sessions with a small group of participants to explore their needs, motivations, and expectations
Clara oucama
Student
Jiaxi Gao
Freelancer
Clement Gautier
Junior manager
INSIGHT
The testing revealed that users have diverse needs and motivations, highlighting the need for a flexible platform that can support different use cases.
PERSONA&STORYBOARD
To better understand the users, I developed two personas to bring different usage scenarios to life and to demonstrate the app’s functionality in a simple and relatable way
Lily
Goals：
Age: 23
Profession: Student
-
Save time and money to make room for more meaningful activities
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Learn about French culture, meet new people, and exchange ideas
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Find simple ways to exchange services or items to make daily life easier in Paris
Lily is a Chinese student studying at a business school in Paris. Living abroad, she faces cultural differences that make daily life occasionally challeng-ing.
With a limited budget and a high cost of living, she often struggles to afford services she needs, which leading to frustration.
Motivation：
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Enable quick and convenient exchanges with minimal effort
-
Obtain needed items or services without financial constraints
Persona 1
See how Lily, a young student struggling with daily challenges finds a simple way to exchange resources and improve her life
Lily moved to France for her studies, driven by her love for French culture.
Living in the suburbs, she spends a lot of time commuting and often feels tired.
She has a heavy workload and doesn’t have time to handle all the housework.
She often overbuys groceries, leaving her fridge full of food she can’t finish in time.
She discovers Knock-Troc online, looking for an easier way to manage her daily life.
She find a person to make the exchange. She offers the food she can’t finish, and in return, he shares his cooking.
Now her life is easier, and she has more time to do the things she enjoys.
Anne
Goals：
-
Reduce daily living expenses
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Get rid of unused items and make better use of resources
-
Make her daily life more fulfilling and meaningful
Age: 42
Profession: House wife
Anne is a housewife who spends most of her time at home. During the day, when her family members are away, she often feels lonely and unsure how to make meaningful use of her time.
As she is not currently working, there is also some financial pressure on the household, which makes her more con-scious about spending.
Motivation：
-
Reduce unnecessary consumption and make daily life more engaging
-
Make better use of unused resources at home
Anne is a housewife who spends most of her time at home and has no personal income.
One day, she wants to do laundry but realizes she has no detergent at home.
She realized that she went to the supermarket yesterday and doesn’t want to go out again.
See how Anne, a house wife make a simple exchange between neighbors turns everyday needs into mutual support.
Persona 2
She finds Knock-Troc online and matches with someone in her neighborhood.
A man who lives nearby offers to exchange his laundry detergent with her.
She washes his clothes twice in exchange for a bottle of laundry detergent.
They both get what they need and feel satisfied.
USER FLOW
Mapping the key steps of interaction to ensure a clear and efficient user journey
*This flow only illustrate one of the key flows, to know more about it, pls contact aurthor.
USER FLOW
To validate the core user flow at an early stage, I created paper prototypes to quickly explore layout and interaction concepts.
By conducting quick usability checks with low-fidelity sketches, I was able to iterate efficiently, reduce design assumptions, and improve the clarity and usability of the overall experience.
WIREFRAME
Low-fidelity wireframes were created to translate insights into a clear information architecture and interaction framework.
WIREFRAMES
This is a place where magic happens
UI PRESENTATION
The high-fidelity prototype translates the wireframes into a complete visual experience, showcasing the final interface design and interactions.
It brings together visual language, and usability to demonstrate how users can seamlessly navigate the app and complete exchanges.
HOMEPAGE
The home page is a place where users can view posts from other users, as well as group information and people they might know
Select a group to see the detail
View posts, members, and information in the group
GROUP PAGE
Users can join different groups to facilitate more targeted exchanges; groups can be created based on type, interest, location, and other criteria
Click the menu icon to open the sidebar, where users can filter the displayed content according to their needs
Click the “Service” button to switch post type, this section primarily features service-related listings
USER'S POST
When browsing other users' posts, you can view the photos they've shared, their descriptions, exchange requests and conditions, and their location. Users' app activity and credit ratings are also displayed
Click the button to chat with the publiser
POST GOODS/SERVICE
Users can create post in the app to share the items they want to exchange and the things they’re looking for
TASK AND MESSAGE
Here, users can view their ongoing exchanges and conversations with other users. After each exchange is completed, users will earn points
FIDELITY PROGRAM
A built-in loyalty program( rabbit points) incentivizes exchanges by rewarding users with points that can be redeemed for products or discounts
Rate partner after exchange
PROFILE
The profile page allows users to change their settings and view useful information, such as the number of trades, posts they've published, and credits points
