Uniting outdoor activity with charity fundraising



trundl Founder, Hilary Mines, came up with the initial idea of uniting outdoor activity with charity fundraising almost twenty years ago when she was running another business. But it was the late diagnosis of a congenital hip condition in 2020 that left Hillary unable to run or participate in the hill walking activities that she loved and made her think again about the idea behind trundl and how she could bring it to life for a much wider audience.

A few months into lockdown and Hil had the good fortune of meeting her business partner, Tess Caven. Tess helped Hil see the benefits that people could get from combining the ‘simple’ act of walking with the motivation of giving back to charity. Their research concluded that the common exercise approach of being first over the line, continuously battling to beat times, distances or other people, was alienating individuals who did not want to make competitive fitness achievements their only goal. They realised that they had the chance to create something very special.

The Idea

trundl approached Bad Dinosaur to help design and develop a subscription-based platform, engineered to help as many people as possible to get out and about and increase their daily step count - to simply, “go for a trundl”. The platform had a subscription based component attached to it with a percentage of the users membership fee being donated to charity partners listed within the app. This innovative crossover of gentle exercise with charitable giving is at the heart of the app’s unique USP.

The Project

The project kicked off with a Product Discovery Workshop in early June, 2021. Bad Dinosaur assembled a diverse and technically experienced team to review the project and understand exactly what was needed from the client.

The trundl team already had a clear understanding of how they wanted the app to work but engaging with the Bad Dinosaur team allowed them to brainstorm the design and technology required to turn the idea into a consumer facing application.

The half day workshop session at Bad Dinosaur HQ was used to map out the user journeys and agree upon key functionality for the app. Shortly after a detailed project plan was agreed upon and the Bad Dinosaur team got to work on designing and developing the platform.

While we were happy with all the developers that we put on our short list, Bad Dinosaur won our overall confidence by balancing flair, innovation and pragmatism in their final proposal. Their caution to ‘keep the MVP simple’ was a wise mantra and has helped us to avoid many expensive pitfalls without compromising design and experience.

Tess Caven, Marketing Director, trundl
Tess Caven, Marketing Director, trundl

The Users

During our workshop session with the trundl team, we outlined various aspects of the project including an analysis of the key personas who will use the platform. This is a key step in our Product Discovery Workshop that helps both the agency and the client to connect with and understand the users of the app.



Tom is recently retired, and spends much of his free time walking his dog, Murphy. Tom lives by the sea in Devon, and is planning to complete the South West Coastal Path over the next couple of years. He hopes to involve some friends and family in some of his walks, but knows they are busy with their working lives, so a way to keep momentum and repurpose his walks for charity is the motivation and value he needs.



Nadia works for a large law firm, and works long days and often weekends too. Her firm does regular corporate fitness challenges like 10k runs and enters the London Marathon and while she would love to participate, she simply does not have the time to train and finds the whole fitness clique quite intimidating. She would like to exercise more regularly though and does give to charity, so she would be interested in how she and like-minded colleagues can raise money for causes they are passionate about without the pressure of running a tremendous distance.

Having been involved in competitive sport when I was younger, I was always fairly fit and ran marathons up into my 40’s. But after a few injuries and a drop-off in fitness I’ve found that motivation to go the gym regularly just wasn’t there. I joined trundl to help test the app, but I’ve surprised myself to find that going out every day for a charity cause is a good fitness incentive, so I’m really proud to now be a founder member of trundl.

Terrence, trundl user
Terrence, trundl user

The App

The trundl app allows users to gently exercise while giving back to charity at the same time. There are three core components to the platform: GO, GIVE, and GET.

The GO aspect of the platform can be classified as exercise tracking, encouraging users to go outside, get their steps in and meet their goals. The app has an inbuilt pedometer, distance meter and timer to track users progress as well as Google Maps integration so users can clearly see their trundls plotted out on a map.

The charity donation from their subscription fee is categorised under the GIVE focus of trundl, with users able to choose from a selection of charity partners that trundl will donate to as part of their membership. Members can also join weekly ‘Community trundls’ for charities that are sponsored by a brand partner or by trundl. Whenever a member presses ‘Go trundling’ on the app, their steps will all add up to a collective goal that is shown in a progress bar on the app.

Finally, the GET element is the rewards section of the app, where members will receive badges, boosts, and physical rewards from both trundl and corporate partners. trundl’s aim is for these offers, if redeemed, to more than repay a member for their monthly fee and generosity of spirit.

Building trundl has been a very interesting and positive experience culminating in a community app that I think each and every one of us can be very proud of, from Bad Dinosaur, to the trundl founding team, and more importantly for our special trundl members. I am very much looking forward to seeing what great things we can all achieve for our health and for our charity partners in the coming years.

Hilary Mines, Founder, trundl

Hilary Mines, Founder, trundl

The Technology

The app has been built as a Hybrid Web App, using Microsoft Xamarin. The backend API was built using .NET Core. .NET is a free, cross-platform, open source developer platform for building lots of different types of applications. It’s a very popular framework amongst developers. To complement this backend technology, we used Blazor to build the frontend of the application.

The Outcome

trundl soft-launched in the first quarter of 2022 and is marketed as a unique, non-competitive membership initiative that is powered via their app. To date they have partnered with four amazing charities: UK National Parks Foundation, MOVE Against Cancer Charity, Sussex Wildlife Trust and Dogs for Autism and are already raising money through trundls.

The trundl team have big plans for the next 12 months with more charity partners joining the platform in line with exciting expansion plans for their trundling community.

Bad Dinosaur has immensely enjoyed working on this project and loves seeing the positive impact trundl is already having on their membership and charity partners. We look forward to working together more in the future!

The trundl team had a clear vision from the outset and I really like the charitable component of the app. Hil and Tess are great to work with and working together has been a real collaborative process, bringing their ideas to life. Now that the app has launched it is great to see people beginning to trundl across the country!

Alex Strachan, Developer, Bad Dinosaur
Alex Strachan, Developer, Bad Dinosaur