SlimFact

Streamlined invoicing made easy

SlimFact is an open-source, API-first invoicing engine. Use it standalone or embed it headlessly into your own software.

• Self-host for free or Cloud at €15/month — all features, no tiers
• tRPC API — type-safe, auto-generated clients
• Fully customizable — Typst PDF templates, custom business logic, your own PSPs
• Online payments — iDEAL, credit cards via Mollie or Stripe

Documentation · Demo · Why SlimFact · Pricing

---

Self-Hosted

Requires Caddy and PostgreSQL.

wget https://raw.githubusercontent.com/simsustech/slimfact/main/docker-compose.yaml
wget https://raw.githubusercontent.com/simsustech/slimfact/main/.env.example -O .env
mkdir env
nano -L .env  # Change environment
nano -L env/POSTGRES_PASSWORD
nano -L env/OTP_SECRET  # openssl rand -base64 32
nano -L env/OIDC_COOKIES_KEYS  # openssl rand -base64 32, comma separated
docker compose up
docker exec -it slimfact-database-1 /bin/sh
MODULARAPI_ADMIN_PASSWORD=yourpassword npm run seed:data

Login with admin@slimfact.app / yourpassword.

---

Development

SlimFact is built on Modular API. Requires private NPM access.

git clone https://github.com/simsustech/slimfact.git
cd slimfact
pnpm i
docker compose -f docker-compose.dev.yaml up
cd packages/api
POSTGRES_PASSWORD="$POSTGRES_PASSWORD" POSTGRES_DB=slimfact pnpm run migrate:latest
POSTGRES_PASSWORD="$POSTGRES_PASSWORD" POSTGRES_DB=slimfact pnpm run seed:demo
pnpm run dev

---

License

Copyright © simsustech 2024-present · ELv2 License

AI

As of June 2026 the development is AI assisted.