Buy & Sell Used Books

BookBuddies: A mobile app concept for buying and selling used books

My role

UI/UX Designer 


3 days

Skills used

  • user research
  • competitive research
  • personas
  • product strategy
  • visual design
  • wireframes
  • hi-fi mockups
  • testing

Tools used 

  • Pen & paper
  • Adobe XD
  • Photoshop
  • InVision


  • Wireframes
  • Hi-fi mockup
  • App prototype

The Problem

We want to design a new app that helps millennials to be well read while keeping their pockets in mind, and also allow them to sell their books that they don’t need anymore via the same platform to the ones in need.

Many people love the actual look and feel (and even the smell) of physical books. Most exam textbooks and coursebooks are a one time read, and are published on an yearly updated syllabus – rendering them outdated after 1 to 2 years. On the other hand many people cant afford to spend so much on brand new books.

Don’t waste a book after reading once, share it!

Why not design a platform/marketplace that connects the two sides and creates a win-win situation?

Business objective: Get more conversions, Simplify delivery logistics


Assumptions and Constraints

Book sharing apps come in various shapes and sizes. I chose to design for a native iOS app in which users can post information for their used books and can also browse and buy used books posted by other users. 

I decided to go down this route, hypothesizing that users are more inclined to download and use a mobile marketplace app with a database of many books with equally many seller options, much like Amazon, than a haphazard marketplace like OLX.

  1. Assume that the process of buying a used book is part of a greater “advancing my career” experience. Choosing used books over new ones simply might not be the cup of tea of some users. 
  2. Since books, novels, and coursebooks are ubiquitous, assume that there is diverse variety of books in any given locality. This makes book owners geographically close to each other, and hence un-complicates delivery logistics.
  3. Assume that the users who would use a mobile marketplace app are technologically savvy and familiar with existing patterns around popular marketplace apps. Conduct a quick audit of familiar marketplace app patterns.
  4. Assume that the marketplace app makes money from sales done from their app. Design should make the overall experience of buying used book as easy as possible and result in increased conversions.
  5. Assume that a business goal is retention. Design should make it rewarding for users come back and use the app again by reducing cognitive load (e.g. saved searches, meaningful defaults, pre-filled forms, etc.)

Guerrilla User Research (Personas)

Listing assumptions uncovered some questions I needed to learn from users. For example, I assumed that most people don’t prefer used books over new ones. But did they really? 

I quickly interviewed 4 people (friends and family) I knew who read a lot and have used apps to buy books and other products online. Asking questions like, “Walk me through the last time you bought a book,” “How and why did you buy a used book,” and “Explain what do you do with books that you don’t need anymore,” I was able to nail down some user behaviors, needs, and goals and synthesized them into user types below.

I came across two types of book connoisseurs: The Novel Lover, and The Exam Preparer. (I’m assuming the Casual Researcher lies in between these two personas.)

"The Novel Lover"

”Once I have a novel in mind, I rush to the nearest Oxford Bookstore or Crossword Store to grab a copy of it. I love the fragrance and the feeling of holding a real physical copy in my hands.”

The hard-copy lover. Typically they always buy books from the same bookstore that they trust. They either call or search the catalog of the bookstore before they go and buy the book. They like collecting physical copies of books and are less likely to share them as used books because of the emotional attachment they develop towards books. 

If they need to buy used books they go to local “book-mandi” market. For example, Chawri Bazaar, Chandni Chowk in Delhi. If they do need to get rid of some old books, they either donate them to a local library, or hand them over to a friend. 

They need to examine the condition of a book before they buy it. Damn, perfectionists! 

"The Exam Preparer"

”I need all kinds of study material available to me, or else I can’t pass this exam.  I will borrow them from friends, and get them photocopied. Or simple yet, I’d buy a copy of them from the market. “The kunji” with previous years solved papers will make me pass this exam quickly and I need it.”

They need hard copies where they can mark and solve questions, and do rough work. They ask for advise from their friends or college seniors as to which study material they should take. If they need to get rid of the material, they typically call a kabaadi-walaa.

They need a sense of trust on the seller, and (dead) cheap rates for used study material.

Competition Analysis

I also took a quick look at some of the apps and websites that users had mentioned:

Book listing and 'post your ad' feature on
Book listing and chat feature on Quikr
Book listing and book detail page on OLX. The sticky call to action is good design.
Other competion websites. They have a poor product with many UX flaws.

A quick review of the competition gave me an inventory of existing mobile patterns, strengths and weaknesses to begin brainstorming designs for these different types of users.


User Flow / Customer Journey

User and Information flow. The 3 persona types are highlighted.

I came up with a list of general requirements for a used books marketplace app and started to work through a user flow of buying a used book.

The structure will be like a typical online e-commerce marketplace app, as defined in the next section.

The Buyer would want to check the condition and price of the book, and will make a positive decision if the Seller is geographically closer. The Seller will want to make profit, and ensure that their ad is discoverable to Buyers. 


Payment Logistics 

I researched two ways that are tried and tested in the current market: 

  1. Direct peer to peer payment using cash or direct wallet transfer (like OLX users do)
  2. Amazon like escrow payment model, where the marketplace sits as the third party between two parties and withholds/releases payments when goods are delivered.

To keep things simple and to keep focus towards the app experience, I decided to go with option 1. 


Delivery Logistics

Once the payment logistics choice was made, the only feasible delivery logistic is that the buyer and seller actually physically meet at a geographically convenient location, and trade the book and payment. The chat interface aids in doing this by presenting short-cut text messages that the user can simply tap and select.

App Flow and Features

App flow for Buyer
App flow for Seller

The above chart shows a tentative app flow and the process by which a buyer can shortlist and buy books, and a seller can post books that they want to sell. 


App Features

The structure will be like a typical online e-commerce marketplace app, with screens for – login/signup, onboarding, search page, search results, product collections/categories, product, seller listing, and a chat interface instead of a cart. The app will also have an interface that allows users to post a free ads about a book that they might have to sell.

Rather than showing a gazillion different ads about the same book to the user, the app will have only one product page per book which will list the available sellers for that book on the same screen. The app will show the condition of the book and the price offered for each seller that is selling the same book. This is done to avoid cluttering of the marketplace, and leading the direction of the marketplace towards a book information community. 


Lo-fi Wireframes

Here are some of the wireframes that I created. 

Hi-fi Mockups

The final mockups incorporated all of the above research and give the vibe of a marketplace with thousands of books. 

Book details screen. Notice the various seller options aggregated in one place.
Chat screen. The quick replies make it easier for both parties to break the ice and have efficient communication.

In the chat screen, as a nice usability feature, I thought to add ‘quick replies’, which enable the Buyer and Seller to break the ice and have a conversation that leads to the closing of the deal.   

InVision Prototype

I assembled all the hi-fi mockups into InVision and made a working prototype of the app. This gave an almost realistic experience to the users with whom I tested the app. Their feedback was noted and it would help me refine the app further in the next design iteration. 

Meanwhile, check the prototype out yourself:

I quickly iterated based on both user feedback and design critiques. While creating the hi-fi mockups, the focus was on the details and UI design. For example, users said, “Book images are the first thing I look at and want to see.” 

The thumbnail icon in my lo-fi wireframes before felt too small. In my final mockups, the search results included wider image sizes and the pricing located right beneath. Adding in real imagery also helped reassess UI decisions.


Next Steps

Next steps would be to test again and see how these concepts fare in the hands of more users. I’d remind myself of the original goal:

We want to design a new app that helps millennials to be well read while keeping their pockets in mind, and also allow them to sell their books that they don’t need anymore via the same platform to the ones in need.

Testing for success and efficiency would be a usability test, which could measure how long it would take for users to buy a book, how successful they are in choosing a specific book based on the specified condition.


Next iterations would also work through more edge cases. Some examples:

  1. Seller interface. An efficient way in which a seller can post information about a book that they want to sell.
  2. Buyer Seller logistics. More research and testing on UI patterns for Seller interface and chat interface. How can we better enable both the parties so that they can meet safely and have a hassle free transaction? 
  3. Empty search results. For example, if the user has searched for an obscure topic or author that has hardly any books. What would happen? Possibly we can add a feature for ‘request this book’?

Final Thoughts

I was surprised to learn that the users I interviewed honestly don’t use mobile apps to buy used book. Buying books, be it new or used — this behavior falls into a mental model of “career advancement.” 

Users in “career advancement” mode need to review information in detail, deliberate with other stakeholders, research and read quality content over time. It makes sense why most users will defer to manual bookstores vs. apps.

Do mobile bookstore marketplace apps design for behavior change or not? That is the question! 

In this exercise, I chose to design for existing behaviors. I learned that the best value a mobile used-book marketplace app can provide currently is during the initial browsing and curation phase of a user’s entire career advancement experience. However, I’m excited to see how our needs may change as we develop new behaviors around used books in the future.

Thank you for patiently reading!

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