Home/Work/SGR-App
● Case Study 02 — Product

SGR-App

A mobile-first club app for a table-tennis club — trainings, messaging, equipment and the club's whole org on one screen. An installable PWA that feels native, with passwordless biometric login.

Client
SG Reudnitz 2011 e.V.
Role
Sole engineer · design + build
Platform
Installable PWA · iOS + Android
Status
Live · in active use
The context

A whole club, run out of group chats and paper.

Like most amateur clubs, everything lived in scattered WhatsApp groups, spreadsheets and a literal logbook for the hall key. Who's coming to training? Who has the key right now? Who do I ask about membership? Nobody could answer without scrolling three chats.

Before
  • Training attendance guessed from chat replies that scrolled away
  • The hall key tracked on paper — and regularly "lost"
  • Announcements, board requests and chatter all in one noisy feed
  • New members onboarded by hand, passwords forgotten constantly
After
  • One-tap attendance with a live list of who's actually coming
  • A digital key pass — full handover history, transfers in 2 taps
  • Separate lanes: 1:1 chats, board inbox, club broadcasts — with unread badges
  • Passwordless login via Face/Touch ID; magic-link invites for new members
Try it

One tap, and the team knows you're in.

The single most-used action in the app. No reply-all, no "who else is coming?" — tap once and the live attendance list updates for everyone. Go ahead, toggle yourself on.

TUE · 19:00
Training · Halle Reudnitz
📍 Sporthalle Reudnitz · Court 2–4
Who's coming 5 on
MK Max K.
LW Lena W.
TS Tom S.
AB Anja B.
JR Jonas R.
Tap to join — your spot shows up instantly
What's inside

The features that carry the app.

Not a feature dump — these are the pillars members actually open the app for, every week.

Trainings & attendance

Week and list views, one-tap "I'm on / Leave", and a live roster of who's coming. Hall, time and a jump straight to the key log.

Messaging that's sorted

1:1 peer chats, a board inbox for requests, and club broadcasts — kept in separate lanes with unread badges and live auto-scroll.

Hall-key protocol novel

A digital key pass per hall. Full handover timeline, two-tap transfers, and bidirectional requests you accept right in the feed.

Passkey login WebAuthn

Passwordless, biometric sign-in with Face/Touch ID. Magic-link invites for new members, multiple devices per account.

Club org, built in

Member management, halls and venues, board roles, an equipment inventory with a request workflow — and multi-club support.

Personal & polished

German/English live toggle, three color schemes, drag-to-close bottom sheets and a floating tab bar. Dark-mode by design.

Spotlight

The hall-key, finally accountable.

The feature nobody expects from a club app — and the one everyone ends up loving. Every hall has a digital key pass with a complete, timestamped handover history. No more "who had it last?"

01
Pick a memberChoose who's taking the key — that's tap one.
02
Confirm the handoverTap two. It's logged to the timeline with time and optional note.
03
Or request it"I'll give the key to X" or "X wants it from me" — accepted right in the timeline entry, withdrawable anytime.
A closer look

Around the app.

Drop in your own screenshots — trainings, chat, key timeline, settings.

Built with

Tech stack.

Angular 21NestJSGraphQL (fully typed)MongoDBWebAuthn / PasskeysService Worker / PWACookie auth (HttpOnly)Dockernginx
On the roadmap
Realtime via SSE
Web Push notifications
League schedule integration
Line-up editor

Got an idea that should be an app?

From a club tool to an internal platform — I design and build installable, production-grade apps end to end. Tell me what you have in mind; I'll reply within 2 hours.

Start a project →