June 2017 – May 2018
The brief
The mobile app was the preferred way for existing customers to communicate with Three, so the company was determined to maximise its potential. I was brought in to:
Support monthly releases to continuously improve the app
Help increase Monthly Active Users (MAU) and Net Promoter Score (NPS)
Design solutions to support marketing campaigns and new propositions
My role
I was the sole Product Designer for most of the engagement, expected to:
perform all user research, UX and UI design
contribute in a ‘T-shaped’ manner (e.g. supporting QA, writing stories for the backlog)
I collaborated closely with:
Product managers, developers and copywriters in a fast-moving agile team
Customer service, marketing and analytics experts
Senior leadership via quarterly playbacks and target-setting
Goals and challenges
Three set ambitious quarterly targets for MAU and NPS. These aren’t perfect UX metrics but they gave me something concrete to optimise against. I delved into usage analytics and verbatim feedback to identify what improvements would make the biggest impact.
There was a wrinkle: back-end changes were off the table due to lead times and cost. To get things done, I’d have to work closely with developers to find creative ways around these restrictions.
Slotting into a high-performing team
I'd joined a tight-knit, high-performing scrum team that had won company-wide recognition multiple times, so I knew I’d have to be at the top of my game. It was made up of veterans who had seen many designers come and go.
Early on, I realised my ideas wouldn’t be accepted at face value. I had to earn their trust, so I:
invited early discussion and critique
presented designs backed with evidence and awareness of what was technically feasible
took feedback seriously, demonstrating I was in it to improve the product, not just to push my own pet projects
I enjoyed working with intelligent, motivated engineers who weren’t afraid to push back. They helped me spot implementation shortcuts I hadn’t considered, and we routinely worked together on navigating constraints to get stuff working.
Each team in Three's digital department was required to present their impact in quarterly playbacks to leadership, and every discipline was expected to contribute. This helped sharpen my storytelling skills, to the point where I was approached by management to share how I structured presentations and handled nerves.
Building trust with an early win
Right away I spotted an opportunity to enhance the app’s most popular feature – checking mobile data allowance. As it stood, there was no way to see usage over time, so customers couldn’t easily understand their data consumption patterns.
I knew that historic data was available, so I proposed a visualisation that would expose this information in an easily digestible manner. This screen could also be used to dynamically target upgrade messaging – a business priority.
After highlighting the potential positive impact, the feature was approved and quickly became one of the app’s most-used features.
Enhanced data usage info, with targeted upsell to customers who would benefit the most
Tackling a bigger problem
After usage, checking bills was the most common reason to open the app. But the existing experience was poor. I analysed customer feedback to confirm the top pain points:
The PDF bill available in the app was totally unsuitable for a mobile screen
There was no view of unbilled usage for the current period
Users couldn’t easily understand where extra charges came from
Although there was no native billing display, I discovered there were API endpoints containing structured billing data — they just weren’t wired into the app and the documentation was lacking. Working with developers, I:
reverse-engineered the API responses, manually comparing JSON data to PDF bills to confirm accuracy
identified available billing attributes (e.g. total charges, categories, individual usage events)
scoped a performant, reliable mobile-optimised billing experience
Designing for clarity
I designed the digital billing flow around what users actually wanted to know:
“Am I being charged more than I expected?”
Early surfacing of extra charges within the bill overview, with clear affordances for digging deeper.
“What caused the extra charges?”
Clear indications of what had incurred extra charges (calls abroad, picture messages etc) broken down into user-friendly categories.
“What’s happening in my current cycle?”
Charges for the current billing period were carefully presented to make it clear that this was usage that won't yet show up in any bills.
Billing prototypes were tested through iterative unmoderated usability studies to validate comprehension, terminology, and discoverability.
New in-app billing flow: the most valuable info is always prioritised
Driving conversion of plan upgrades
Towards the end of my engagement we were set a new target: significantly increase the uptake of the 'Change Price Plan' proposition. This allowed customers to move up to the next data plan for a flat fee without restarting their contract.
What I observed: the feature had a vague, unappealing name and wasn't positioned well. Users didn’t understand it or see it at the right time.
What I changed:
Reframed how the offer was messaged, highlighting its no-commitment benefits.
Positioned it in contextually-relevant places. For example, one off 'add-ons' were popular but the little-used 'change price plan' offer was actually better value, so I made sure we emphasised this during the add-on purchase funnel.
Dynamic surfacing: we highlighted the offer to customers who’d benefit the most i.e those who regularly went over their monthly allowance and those on middle-tier plans.
The impact: in-app sales increased by 40%
Surfacing the 'Change plan' option based on customer intent and data usage
Outcomes
By overhauling and enhancing key app features, my work contributed to:
Rising Net Promoter Score, into the ‘great’ category (mid-30s)
Sustained MAU growth, by improving the most-used areas of the app
Team-wide recognition, including “best performing squad” accolades and leadership praise
Reflections
My time at Three challenged me to hone my product focus: to sell the value of my ideas, to get stuck in with awkward technical issues, and to focus my effort on things that'd move the needle on key metrics.
I was recognised for my contributions, both during my time on the job and also afterwards, when I was independently sought out by the Head of Digital In-Life and the Head of Design to work with them again.
“You were always absolutely phenomenal at getting to the roots of problems and finding ways to get around constraints to make it awesome.”
Head of Design, Three