Schwimmen für alle Kinder
Tübingen-based initiative for free swimming lessons – TuKs admin software (predecessor of Ondu), coach app, website with course booking, and a newsletter that reaches more than 1’400 recipients.
- Client
- Schwimmen für alle Kinder (SFAK)
- Year
- seit 2020
- Location
- Tübingen, DE
"Schwimmen für alle Kinder" provides free swimming lessons for children and teenagers from socially disadvantaged families in Tübingen. We've accompanied the association since 2020 – from the first Excel sheets through the rollout of Google Workspace (for Nonprofits) to today's stack: TuKs admin software (predecessor of Ondu), coach app, website with course booking, and newsletter.
Swimming that shouldn't fail over money.
"Schwimmen für alle Kinder" is a Tübingen-based initiative that provides free swimming lessons for children and teenagers from socially disadvantaged families in the Tübingen district. Active since 2015 under the Förderverein Lokales Bündnis für Familie Tübingen e.V.
Volunteer swimming instructors run the courses. The office coordinates enrolments, schedules, and the allocation of open spots – in 2025 for 470 children, across 119 courses, in 12 pools in the Tübingen district.
Inclusion is part of the mission: SfaK offers courses for children with disabilities, led by instructors specifically trained for it.
Software that grows.
Rapid growth and permanently high enrolment and course-occupancy numbers call for a multilayered, flexible software stack – administratively efficient, with a clear overview of all participants, and GDPR-compliant.
- TuKs – participant and course system with signup inbox, scheduling, allocation
- Coach app – running courses at the pool
- Website with course booking – public enrolment flow
- CMS – Strapi as headless CMS for news and page content
- Automations – confirmations, reminders, GDPR anonymisation
- Newsletter – more than 1’400 recipients, digital design and dispatch
From spreadsheet to system.
SfaK has existed since 2015. Our collaboration begins in 2020 – with Excel sheets: enrolments by email, course lists as files, overviews assembled on demand. With every season it got clearer that the initiative's growth needed a system of its own.
We moved step by step – together with the SfaK team, always along the bottlenecks the association felt first in daily work. First TuKs as the admin backbone. Then the website with course booking, feeding enrolments straight into the TuKs inbox. With Strapi as CMS, editorial independence followed later. Google Workspace and @sfak.de mailboxes gave the team a coherent presence – later including Google login for TuKs and the coach app with two-factor authentication. The coach app and the newsletter automation completed the system.
With the server move to Germany came digital sovereignty – GDPR compliance without detours, with certainty over where the data sits and who is responsible for it. A value any non-profit knows, when its data on families, children and health-related notes converges in the office. Hosted at Hetzner in Nuremberg: 100 % renewable energy, low-latency connections and resources that scale vertically as the system grows.
Each step solved a concrete problem. Over six years, a system has grown that is in daily use today.
Sign up, review, allocate – in one system.
TuKs, the participant and course system, is the association's admin backbone: a NestJS API on Postgres with an Angular admin UI for the office. The system manages the operational master data – pools, pool operators, locations, team and user accounts – and connects them with the live course schedule. Enrolments from the website land in an inbox, get reviewed, and are converted into participant records. From there, coordinators assign them to scheduled courses.
The courses view is where the office spends its day: server-side filters and sorts across thousands of records, direct editing of schedules and instructor assignments, open spots and waiting-list status at a glance, year-on-year statistics per pool. A graduated role system from helper to admin makes sure nobody can change (or enter) more than their role permits.
TuKs was the starting point for more. From building and running it for SfaK, Ondu emerged – a configurable system for associations, clubs and SMEs. VFAP Akademie was the first external client.
Find a course, secure a spot – no detour.
The website shows the course offering clearly and takes the signup itself: families see location, pool, age group, schedule and open spots per course.
The signup runs in two steps – first whether the family is already known to the association, then capturing the data for the child and the responsible adult – including health notes, stored in the system and accessible to instructors directly in the app at the pool's edge. Confirmation follows once the office has reviewed the entry and assigned it to a course.
The form transfers directly into TuKs's signup inbox. From there the registration is reviewed, classified – and for new children, converted into a participant record. From that point, assignment begins.
Alongside the course booking, the website has its own editorial area. Strapi as a headless CMS makes the association independent – the team manages news, season updates and page content itself, straight from the browser. What started as a static Next.js site is now editorially self-sufficient.
What repeats, runs by itself.
Some tasks repeat themselves course after course – confirmations, reminders, data hygiene. What the system can take on, it takes on – so the office has time left for the work that needs hand and head.
Regularly a bundle of jobs runs: course confirmations for newly assigned participants, course reminders with time and location sent shortly before the start, attendance confirmations – parents and carers are asked in advance whether the child will come – reminders to families whose funding is up for renewal, statistics updates for the current year, anonymising personal and contact data once the retention window is over. Every run is logged – the office sees what happened and what didn't.
These routines hold together what would otherwise slip: timely communication, correct numbers, deadlines met – reliability and care as a system property, not as extra effort.
Wet hands, clean data.
With the coach app, TuKs is right there at the pool's edge – attendance, course data, health notes – what happens at the pool lands directly in the system.
The app installs as a PWA – straight from the browser, no app store – and works even on a weak signal or no connection at all. In the course overview, instructors filter and mark courses as favourites – per course: master data, participants and all dates. Per session: take attendance, confirm roles, leave a short note, tap to contact the parents directly – and as a side effect, the system tracks teaching units per instructor. Per child: emergency contact, health notes, current training level (Seepferdchen and beyond) and absences this season – everything at a glance, no call to the office needed.
It also works with wet hands – the interface is built for the pool's edge, not the office. Fewer follow-up questions, more time for the kids.
«TuKs and the coach app have become indispensable in our daily operations. The many courses, participants and instructors are easy to organise with TuKs. The coach app helps with attendance at the pool. Everything is simple to use. The same goes for signing children up via our homepage. Parents find an overview of open course spots and can register their child for a suitable course. And RPEL always has an open ear — for the support we need and for new ideas.»
More than 1’400 recipients, one voice.
Several times a year the newsletter goes out to more than 1’400 families, instructors and supporters – with everything happening at SfaK: new courses, season starts, team news, association updates, awards and more. Concept and dispatch are on us – the content comes from the association.
Subscribing and unsubscribing runs straight through the website, GDPR-compliant with double opt-in on signup and one-click unsubscribe in every issue. Templates follow the association's brand – whether on a smartphone, in the browser or in the inbox.
From the first trial run, a reliable channel has grown over the years. Reach and deliverability grow with the initiative – so that news from the association actually reaches people.
A partnership that has held since 2020.
What has been built here, we built together – not for the association, but with it. Dagmar Müller, honorary chair and founder of SfaK, was the driving force behind the digitalisation – with a clear ambition to improve and automate processes wherever possible, her husband Gerd always there as technical support in the background. Manuela Sacherer and Monika Bösing have since taken over as co-chairs.
On the association's side, Thomas Lacour carries IT and data protection responsibility – he co-developed the database concept and knows what the system needs to deliver. Adrian Wendt works at the interface between system and pool: specifications, training, feedback from the team – he makes sure changes don't just land in the system but are actually understood. Sarah Müller coordinates TuKs day to day: reviewing enrolments, making assignments, managing contacts – she knows the system from the inside because she works with it every day.
We meet regularly and develop together – the system, the processes, the way it's used. What could be improved, we discussed and changed together. A success story of working as partners.
That's how we build software that fits the association!