Carlitos Wafers A UX case study


This case study is based on a cafe, within a the office block of a large multinational, outside of the M25 corridor. So due to the location of the offices, this was the only shop selling any kind of refreshments. Due to COVID 19 measures which were put into place when some offices opened up in 2020/21, due to social dancing, and a limit on the number of people who could congregate in a venue, the queues of people buying at the cafe grew quite long. This case study looks to address that problem.carlitos wafers ux case study cover image



To Design a solution that enables employees to order their beverages/snacks in advance, in order to minimise queues, due to social distancing. Bring order times down from 6min/order to a max of 2min/order on average. (Order time is defined as: User browses, user choses, user pays, user collects items.). This will take the form of a mobile app.

Long Term

Morning coffee/tea, at the office, is a ritual of arrival, in my experience, the longer the commute, the more this is necessary. It’s more than just a stimulant to wake a person up in order to perform. It’s an experience of a sense of - “Welcome”. Long term any solution should aim to embody this experience.

The problem statement

Users at the cafe faced long queues, staff were frustrated, as things as they currently stood meant that users felt rushed when placing an order. Payment with cash was also a problem as it ate up time, and orders where there was more than 1 item were being rushed. Some customers were also opting to forego their morning coffe/breakfast, due to time pressures. Meaning a loss in revenues for the cafe.

Solution rationale

Based on our research we built up a number of personas and user flows. These revealed, that among the usual needs and pain points, the commute distance is an important factor, in user buying decisions. Something I had not initially anticipated. Another point was tenure. People who had been at the company longer had a more established pattern of ordering the same items.

These highlighted a number of opportunities, that could form features in the app that solve the key problems.

Just to recap, the problems beings solved are:
 Reducing the queues due to social distancing Setting up a fast payment method Making menu choices easier to make thus faster, once again to reduce queues The solution I envisaged was an Mobile app, rather than a website. Research has suggested, that most users, are coming to the buying decision (Breakfast beverages and snacks), on impulse.

A mobile app would allow users to make a purchase while on a commute, or in traffic. One possible solution would be to setup a slot pre-booking system, I would hesitate with that as a solution here, because generally people want their coffee hot and their Croissants toasty. And users making a long commute will be hard pressed to state an exact arrival time. Instead I would suggest a system, where the app might work, on the basis of user distance from the shop via location, and size of order, to allocate queue position. We could also send a push notification to the user in the morning, just to setup the suggestion to order via the app.

Payment can be sped up by asking users to register with their Paypal account/google/facebook. On checkout, once credentials are saved, they’d only need to confirm the transaction and input a password. Where users don’t wish to adopt this option, the app could “save the card”. Speeding things up. Some users may be unwilling to take this option, or unable to. So as a backup users can register and pay in the traditional way. The hope is though, that they would opt for the faster method. Preferably with Paypal.

With regards to product choices, it would make sense to group by Category, alphabetically. And set up “combo” meal deals based on the most popular combinations users by to speed up order preparation and dispatch. And setup the Combo orders on the homepage, so users can pick a combo immediately. The order process can be further sped up, by the setup of a my favourites section in the orders menu.

Where users choose what they order in 1 click. To alleviate the wait further for users that are extremely time conscious I suggest a delivery service, at a premium price. Which delivers to the users desk. This would only be used by users in a massive rush, as its around 50% of the cost of an order. Discouraging ordinary users from taking this up. As staff numbers are a constraint. In terms of creating the experience of “Welcome” and “arrival”, the app can send push notifications pre-order, once the order is placed, and once the user enters the building. All based on location. This solution would require testing, and refining based on the principles of design thinking. I’d suggest these features as a beta version. We can refine things as we learn more.



Research provided revealed that the users were a mix of demographics, ages and genders, positions within the organisational hierarchy. Around 70% of the staff at this particular head office had used the cafe at some point.

My Role

  • Product Design
  • Interaction design
  • Wireframing
  • Prototyping the final solution


Research via contextual enquiry with staff, and a survey aimed at pre selected users had revealed an interesting mix of factors:

  1. Users precieved their morning coffee, as a ritual of "arrival", coffee here could be substituted by water, tea, or a snack. It was being used as a device to induce "comfort"
  2. This ritual was influenced to a great degree by the length of the persons commute, the longer the commute the more it was deemed necessary
  3. Tying into the factor above the persons tenure, also played a role in how much variability would exist in their order choices. People with a longer tenure had a more established pattern of ordering. People newer to the business were inclined to seek more variety.
  4. Most people bought on impulse. Impulse in the sense that the thought of getting a tea/breakfast/snack, usually occured once they were on the commute. Not the night before or at a different time. Buying choices sometimes based on influence, and sometimes pre-determined

Scope and Constraints

1. I’ll use the Breakfast period as a scenario 7:00am - 9:00am, this can be applied to other busy times such as lunch 12:30pm - 2:00pm. 2. Capacity considerations: Assumed at 150/day for Queue Mngmt. 
In a real life scenario, this would be worked out by the number of customers visiting. No of staff present. and time per order.
 3. 3 staff in the kitchen prepping drinks & pre cooked snacks. 3 at the counter. Additional capacity for 3+ more during busy periods. 4. Assuming, on average 6 mins/order for a multi item purchase. Includes, browsing, ordering, paying & collection. Goal is to bring this down to 2min.


Research revealed 3 personas, the first one slightly borders on the extreme, but this is a user that orders multiple items. The other 2 users order 1 item usually, and occassionally will order more.

user persona_01

user persona 02

user persona 03

User Journey maps

I mapped two sets of user journeys based on the personas. The first is for a multi item order user. The second is for more casual 1 item purchase users.
Product design/features highlighted included:

  1. Creating an app for ordering, which would manage the queues, an app specifically as most users purchased on the commute
  2. One time registration, with the option to use Paypal/apple pay, once the user has registered, placing an order and paying is achieved in a minimum time and clicks
  3. Creating a "combo meal" product based on the most popular combinations ordered by the users, for faster ordering.
  4. Including the option to re-order previous orders, by creating "favourites"
  5. Offer a premium "desktop delivery" option at aprox, 50% of the order price that a user can use when queues are too long. The Rationale behind this is to keep staffing costs down for the cafe. If too many people were to opt for this option, they'd need to hire more staff.
  6. Using Personalisation in the app, in order to offer users what they ordered previously, or related order items
  7. Organising the menu by Category/Alphabetically in order to make faster buying choices
  8. Sending the user push notifications, when an order is in the basket, and another based on location when they enter the building

user journey 01

user journey 02

User Flow

The user only need to register/login once. Once logged in, the app saves their credentials for fast ordering. There is though a login option, if and when a user deletes their credentials or changes device.

user flow

Wireframe Screen Mockups

wireframe mock ups

Final UI and Prototype

Final UI and Prototype video


At this stage, based on Design thinking principles, it would be prudent to set up:

  1. A Benchmark time test to see if order times are reduced as set out as a goal, from 6min to 2min, to see if that reduces queues
  2. Usability testing of the app, before rollout, and after rollout would also be advisable
  3. Interviewing staff and customers, to see whether satisfaction levels are higher or lower, post app deployment.
  4. Use these learnings to further refine and develop the app.