Deductions

Desktop app for collecting invoices for tax declaration preparation.

What Deductions Does

Deductions helps people in Germany collect invoices and receipts to save money through income tax deductions.

You may know that certain expenses can lower your taxable income, but the supporting documents are often scattered across email inboxes, online shops, PDFs, photos, local folders, and paper receipts.

Does this sound familiar?

1. You postpone collecting them until close to the tax deadline.
2. You have to remember what was purchased and why it was tax relevant.
3. You search for missing invoices and receipts under time pressure.
4. Even if a tax consultant files the return, you still have to collect all the documents, which is time-consuming.
5. You lose money by missing items or not filing your tax return at all.

The app transforms this task from a late, stressful, memory-based activity into an automated, AI-assisted, money-saving process.

The app is not a full tax declaration assistant. Use one of the existing services for that. Its job is to reduce the manual burden of finding, collecting, classifying, explaining, and exporting invoices relevant to deductions. Simply create a neat handover package for tax consultants or your own tax declaration, and start saving money.

Build and Run From Scratch

Prerequisites:

• Node.js and npm.
• A local clone of this repository.

Install dependencies:

npm install

Start the app in development:

npm start

AI Features with LM Studio

AI-assisted document processing uses a local LM Studio server. Before starting Deductions, load gemma-4-e4b-it-mlx in LM Studio and start its local server. With no additional configuration, npm start uses this model at http://localhost:1234/v1.

To use another model, load that model in LM Studio and override the default for the command you run:

DEDUCTIONS_AI_MODEL_ID=your-model-id npm start

Other Development Scripts

Run the standard checks during development:

npm test
npm run lint
npx tsc --noEmit

Package the Electron app locally:

npm run package

Run end-to-end tests:

npm run test:e2e

The end-to-end test command packages the app first through pretest:e2e.

Database Migrations

SQLite schema is defined in TypeScript at app/main/data/schema.ts. Drizzle Kit generates migration files into app/main/data/drizzle.

Generate migrations with:

npm run db:generate

This uses drizzle.config.ts, which points Drizzle Kit at the schema file and migration output folder.

Generated migration artifacts should be committed as-is:

• app/main/data/drizzle/*.sql
• app/main/data/drizzle/meta/_journal.json
• app/main/data/drizzle/meta/*_snapshot.json

Do not hand-edit generated migration files unless a migration genuinely needs custom SQL. If custom SQL is needed, document why in the migration review.

Manual Drizzle Command

To manually create the initial migration with the current naming convention from an empty migration folder:

npx drizzle-kit generate \
  --dialect sqlite \
  --schema ./app/main/data/schema.ts \
  --out ./app/main/data/drizzle \
  --name initial \
  --prefix index

After generating migrations, run:

npx tsc --noEmit
npm test
npm run lint