Usability and UI design
Usability and UI design in practice: a heuristic-based redesign
Context
Bootcamp UX Design Ironhack
My role
Design Challenge
Redesign four screens of a well-known native mobile app to improve its usability. The focus was on applying Nielsen Norman’s usability heuristics — without conducting UX research.
When ?
2 days in November 2025
The first step was an heuristic evaluation using Nielsen Norman’s principles.
Introduction
This was the third mini project of the bootcamp — a UI challenge focused on improving the usability of a mobile app.
The project followed a course on Nielsen Norman’s 10 usability heuristics, method for evaluating the usability of digital products.
Choosing the App
For this project, I chose Wecasa, a French app that allows users to easily book at-home services such as hairdressing, cleaning, childcare, or massages.
The visual identity is strong and consistent, with bright colors and a touch of humor that create a sense of friendliness and ease.
Why Wecasa?
I had already used the app several times and loved the concept — it’s a smart solution for busy people who need trusted professionals for home services.
However, during my previous uses, I felt some friction in the booking process. I wanted to understand what caused that discomfort and find ways to make the experience smoother.
That’s why I chose to focus on redesigning the booking flow.
Heuristic Analysis
The first step was an heuristic evaluation using Nielsen Norman’s principles.
I analyzed the app in two ways:
- Starting from each heuristic and checking how it was (or wasn’t) applied in the interface;
- Starting from the moments where I felt friction as a user and identifying which heuristic was being violated.
This approach helped me identify several usability improvement opportunities.
Competitor Analysis
I carried out a competitor analysis focusing on the usability improvement opportunities identified:
- How mobile apps display multi-step progress in booking processes;
- How date and time selectors are designed on other booking platforms.
Improvement 1 — Helping Users Visualize Their Booking Journey
This improvement relates to Nielsen’s first heuristic: Visibility of system status — users should always know where they are and what’s happening.
In the current version, users go through several booking steps (at least 7) without any visual indicator showing their progress.
This lack of feedback can make the process feel longer and uncertain.
To address this, I added a progress bar at the top of the booking screens, with clear step numbers and labels.
The design remains clean and minimal, consistent with Wecasa’s visual identity.
This small change helps users feel oriented and reassured throughout their journey.
💬 Feedback from presentation: Be mindful of how the progress bar placement may vary between iOS and Android systems.
Improvement 2 — Simplifying the Time Slot Selection
This improvement is linked to Nielsen’s fourth heuristic: Consistency and standards — interfaces should follow familiar patterns so users don’t have to guess how things work.
In Wecasa’s current flow, date selection happens across three screens, forcing users to move back and forth, which feels heavy.
Each day displays around 30 half-hour slots — too many to scan easily.
The challenge with this feature is that Wecasa allows users to book multiple time slots over several days, and at this stage, users must be able to view the selected slots over several days.
A study of the competition showed that many applications use accordions and sliders for date and time slot selection features in order to display a large number of choices without changing screens.
In my redesign, all dates and times appear together on one screen.
Time slots are grouped by part of the day (morning, afternoon, evening) for better clarity.
Users can scroll horizontally to view months, days, and available slots.
When a slot is selected, the basket automatically updates, and the chosen day turns light orange.
I have thought about the different display states for a ‘day’ so that the user understands :
- what is the current days,
- what is the selected day,
- and on which day they have already selected slots.
It was a bit challenging to reproduce the full interactivity in Figma — it would have required more time and advanced knowledge of variables and actions and …also to be tested!
💬 Feedback from presentation: Good work with components in Figma. Be vigilant in ensuring a clear understanding of the meaning of the different day statuses.
Conclusion
These improvements aim to make the booking journey simpler, more consistent, and more reassuring, giving users a stronger sense of control and confidence.
Off brief or not ?
At the end of the project, I felt I might have been slightly off brief — the assignment asked us to focus on four specific screens, while I spent most of my time refining the booking flow and especially the date and time selection tool.
However, during the presentation, I didn’t receive any comments about that, so I guess my work still met the challenge…
The instructor did mention that she would have liked me to add a more personal graphic touch to my redesign.
Personal Takeaways
- I really enjoyed analyzing the app through the lens of usability heuristics — it provided a solid and methodical foundation for design decisions, almost like a scientific approach.
- I realized that UI design is not only about visuals, but also about the micro-interactions and animations that guide users, support understanding, and enhance readability and fluidity.
Animations are part of usability: they give rhythm, feedback, and coherence to the experience. - Finally, the 5-minute oral presentation followed by peer and instructor feedback was very insightful and helped me step back and reflect on my design choices.
