Redesign Case Study: Carousell

Yay! I’m finally trendy and doing one of these redesign case studies. This one is going to be a redesign of a used-item marketplace app, Carousell.

My ultimate goal for this redesign:

to help sellers accept the ‘best’ offer.

Back when I was living in Boston, I had to sell all of my furniture when I was moving. It was not fun, especially when I knew my lease was ending super soon. I tried using used-item marketplace apps like Letgo, for instance. Although I got a few people interested in buying one of the shelves I posted, I found the experience kind of awkward. Some people gave me higher offers than the others, some just disappeared after I agreed on selling it to them, and some were just super creepy…

I ended up selling all my stuff through Craiglist.

Now, for the redesign…


The first thing I did was identifying what ‘best’ means. I created a survey of 2 questions and posted it on my Facebook. I got 27 responses over 2 days and here are the results:

I found that..

• Most people care about the price

• People would just sell the item to whoever contact them first (assuming that only if the price is reasonable)

  • People don’t worry about delivery method much

Usability Test

I decided to do a usability test with some of my friends to learn more about the user’s pain points. I gave them a very specific prompt.

“You’ve put your used mouse up for sale for $30. People are interested in buying it. Who would you sell it to?”

Out of the 7 people..

7/7 : Age 25–30

4/7 : Have experienced selling things online before

6/7 : Would sell stuff they don’t use rather than just throw it away


I sorted the data I got from the test into important user journey steps for selecting who to sell the item to.

I plotted out the notes I took from the test and identify the common pain points for each of these pages.

Pain Points chart


I paid closest attention to the product offers page since it’s where the sellers make most of the decision of who to sell the item to. I made this empathy map to understand the users more.

Empathy Map for Product Offers page


Taking the information from the testing and analysis, I defined the user’s pain points as followings:


I went ahead and sketched out some alternative ideas. I validated the ideas with a few people I know, and made a higher resolution wireframes on Sketch.


With the wireframes, I made an interactive prototype on Invision and showed it to some people, both in person and through live screen sharing.

In person and Live screen sharing user testings

Happy feedback:

• The offer button on Product Profile page is now very easy to see

Not-so-happy feedback:

• The sort by filter on Product Offers page was not visible enough

  • Too difficult to go to the product detail page if it’s a long chat


For the Product Offers page, my objective was to make the sort by filter as clear as possible for the new users. I prototyped and tested a few iterations until the users were able to efficiently sort the list by highest offer.


The new Invision prototype shows that out of 3 people..

100% : See right away of where to go see the offers

100% : Used the sort by filter options to choose the highest price

Product Profile Page
Chat Page
Product Offers Page

Here’s the link to Invision prototype:

Thanks for reading!