Braingreen

Our flagship project, the Bottle Challenge, makes it easier to cut down on single-use plastic. Through our app, users can find nearby cafés, restaurants, and venues that will refill their water bottles for free. Each refill earns points that can be exchanged for rewards such as cinema or theatre tickets.

Hundreds of venues across Europe already participate, offering free water in return for positive visibility. This simple exchange helps reduce unnecessary plastic waste, while also connecting people with local businesses.

We also run educational programs and awareness campaigns to show how everyday choices — like carrying a reusable bottle — add up to meaningful impact.

We are a team of volunteer IT and web design professionals and we are looking for new volunteer developers familiar with any portion of our tech stack:

Mobile App

• Core stack: React 19, React Native 0.79, Expo SDK 53, React Navigation, Zustand state management, NativeWind styling, plus Expo service modules

Web Frontend

• React 19 and react-scripts 5; codebase is plain JavaScript

Backend

• Django project (Python) driven by the standard manage.py entrypoint
• Django 5.2 with Django REST Framework, dj-rest-auth, JWT auth via djangorestframework_simplejwt, CORS headers

English communication is enough, most of us also speak Polish.