What is OpenKSeF?

Beta

OpenKSeF is in beta. The project is actively developed -- there may be changes in the API, database structure, and configuration. Use in test environments or with full awareness of the current state of the project.

OpenKSeF is an open-source system for synchronizing and browsing invoices from the Polish National e-Invoice System (KSeF). It enables automatic invoice downloading, browsing through a web portal or mobile app, and managing multiple companies from a single instance.

Who is it for?

OpenKSeF is designed for:

• Developers and administrators -- who want to run their own instance and have full control over invoice data
• Accountants and business owners -- looking for a simple, free tool to browse invoices from KSeF
• IT teams in companies -- that need a self-hosted solution compliant with Polish regulations

What can OpenKSeF do?

Feature	Description
Invoice synchronization	Automatic background downloading of invoices from KSeF
Web portal	React SPA with dashboard, invoice list, company management
Mobile app	.NET MAUI for Android and iOS with push notifications
Multi-tenant	Multiple companies on a single instance, per-user data isolation
Push notifications	SignalR (local) + relay/Firebase (remote) + email
Security	Keycloak (OIDC), KSeF token encryption (AES-256), HTTPS
Self-hosting	Docker Compose -- one command and you're ready

Architecture

┌─────────────────────────────────────────────────┐
│                  Docker Compose                  │
│                                                  │
│  ┌──────────┐  ┌──────────┐  ┌───────────────┐ │
│  │   API    │  │  Worker  │  │ Portal (React)│ │
│  │ (.NET 8) │  │ (.NET 8) │  │               │ │
│  └────┬─────┘  └────┬─────┘  └───────────────┘ │
│       │              │                           │
│  ┌────┴──────────────┴────┐  ┌───────────────┐ │
│  │     PostgreSQL         │  │   Keycloak    │ │
│  │                        │  │   (OIDC)      │ │
│  └────────────────────────┘  └───────────────┘ │
│                                                  │
│  ┌──────────────────────────────────────────┐   │
│  │          nginx Gateway (:8080)           │   │
│  │    / portal  /api/ API  /auth/ Keycloak  │   │
│  └──────────────────────────────────────────┘   │
└─────────────────────────────────────────────────┘
          │
          ▼
  ┌───────────────┐         ┌──────────────┐
  │ Mobile app    │         │    KSeF      │
  │ (MAUI)        │         │  (MF API)    │
  └───────────────┘         └──────────────┘

Web portal

Mobile app

Invoice list	Invoice details	Payment QR code

Next steps

• System requirements -- what you need before installation
• Quick start -- up and running in 5 minutes
• Setup wizard -- step-by-step configuration