Photograph a shared grocery receipt, pick who's splitting what, and it uploads the photo to Nextcloud, shares it, and creates the matching bill(s) in Cospend automatically.

Quick Start

# Install dependencies
./install.sh

# Start both backend and frontend in tmux
./run.sh

The app will be available at http://localhost:5173 (frontend) and http://localhost:5000 (backend).

Docker

cp backend/.env.example backend/.env   # fill in, see below
docker compose up -d --build

Available at http://localhost:8080 (override with FRONTEND_PORT). Put your own TLS-terminating reverse proxy in front for anything beyond localhost, and set SESSION_COOKIE_SECURE=true once you do.

Tech Stack

Frontend: React, Vite, TypeScript, Tailwind CSS, installable PWA
Backend: Flask, SQLite
Auth: Nextcloud Login Flow v2 - each user logs in with their own NC account, no shared credentials
Receipt extraction: any OpenAI-compatible vision model (OpenAI, Gemini, ...), configurable, not hardcoded to one provider

How it works

Take a photo of a receipt (or drop one in on desktop).
A vision model extracts the store name, date, and line items - fix anything it got wrong.
Tap items to include them (splits with everyone by default), or expand one to pick specific people instead.
The app groups items by identical split and creates one bill per group - a Cospend bill can only have one split, so a receipt with a "shared" item and a "just me" item becomes two bills automatically.
Each bill's photo is uploaded to the submitting user's own Nextcloud files, shared as a public link, and the bill is created in Cospend with that link in its title (Cospend's UI only picks up a link there, not in the comment) and an itemized breakdown in the comment.

Configuration

Copy backend/.env.example to backend/.env and fill in:

Your Nextcloud server address
A vision provider (base URL, API key, model) - OpenAI, Gemini's OpenAI-compatible endpoint, or anything else speaking that API
TOKEN_ENCRYPTION_KEY (generate with the command in the file) - encrypts stored Nextcloud app passwords at rest

There's nothing to configure for auth beyond that - users log in themselves via Nextcloud, nothing is hardcoded per-account.

Project Structure

backend/
  app/
    auth.py, auth_routes.py   # Nextcloud Login Flow v2, sessions
    nc_client.py               # WebDAV upload + public share (per user)
    cospend_client.py          # Cospend OCS API (per user)
    llm_client.py               # receipt -> {store, date, items} extraction
    routes.py                   # /api/* - receipts, groups, bills
  schema.sql                    # users, sessions, receipts, groups
frontend/
  src/
    components/
      LoginGate.tsx              # login flow UI
      CaptureStep.tsx            # photo capture / drag-drop
      GroupStep.tsx               # item review + splitting + submission
      SummaryStep.tsx
    api.ts                       # backend client

Documentation

PLAN.md - original feasibility research and architecture plan (Nextcloud/Cospend API details, verified against real source)