E-Invoicing SaaS (ZUGFeRD/GoBD)
E-Invoicing SaaS (ZUGFeRD/GoBD)
The business model of this SaaS application uses a transparent, user-friendly freemium and subscription approach. The software is designed for small and medium-sized businesses, tradespeople, and freelancers who face the B2B e-invoicing requirement effective since 2025 and need a simple, no-nonsense solution instead of cumbersome ERP systems.
Monetization is achieved through several pillars that enable steady, predictable growth:
Freemium entry: A permanently free basic plan removes the initial barrier and lets potential customers try the platform without commitment.
SaaS subscriptions: Tiered premium plans, billed monthly or yearly, provide higher quotas for invoices and quotes. Billing is fully automated via an integrated payment provider.
Top-up packages: A fair option to purchase one-time credit packages lets users avoid upgrading to a more expensive subscription when they exceed their quota. This approach builds trust and drives very high customer retention.
Why the price is justified
The asking price reflects not just an idea but the value of hundreds of saved development hours and immediate market readiness. You are acquiring a turnkey, rock-solid foundation that can be scaled right away.
Massive time and cost savings: Correctly implementing the legally required ZUGFeRD 2.3 (COMFORT) XML structures and dynamically generating legally compliant PDF/A-3b documents is technically complex. Building this in-house would cost many times the current price and take months.
Modern, future-proof architecture: The application is not a hastily assembled prototype. It is built on current, high-performance standards and clean architecture with multi-tenant database structures. The system is designed to remain stable and fast even with thousands of users.
Ready-made infrastructure: Secure user authentication, database management, automated invoicing, and payment processing are already seamlessly integrated.
High demand: The solution addresses an acute, legally mandated pain point in the German B2B market.
A buyer—whether an IT systems house, an agency, or an investor—acquires a well-thought-out, clean, and honest piece of software that can be marketed and monetized immediately under their own brand.
Tech Stack
Architecture & Framework: .NET 8 (C#); Clean Architecture (Split into .Web and .Core projects); Blazor Server (SignalR/WebSockets) UI & Frontend: MudBlazor (v8.12.0); Database & ORM: Entity Framework Core (v8.0.20); Microsoft SQL Server (Microsoft.EntityFrameworkCore.SqlServer); Cloud Infrastructure (Microsoft Azure): Azure App Services (Hosting); Azure SQL Database; Azure Blob Storage (Azure.Storage.Blobs v12.25.0); Azure Application Insights (Microsoft.ApplicationInsights.AspNetCore v2.23.0) for telemetry/monitoring; Azure Data Protection via Blobs (Azure.Extensions.AspNetCore.DataProtection.Blobs v1.4.0); Server Location: EU/Germany (Region Germany West Central); Authentication & Security: Google Firebase (FirebaseAdmin v3.0.0 & FirebaseAuthentication.net v3.7.2); Document & E-Invoice Generation: QuestPDF (v2025.7.3) for rendering the PDF/A-3b documents; ZUGFeRD-csharp (v17.4.0) & ZUGFeRD.PDF-csharp (v17.4.2) for XML creation and PDF embedding; Payment Processing: Stripe (Stripe.net v49.1.0);
Key Competitors
Marketing Channels
SEO
Markets
Germany
Target Group
Side businesses, small and micro-enterprises that do not want to afford bloated invoicing and/or ERP software or would simply find it too complex.
Monetization
Subscription for use
Monthly Costs
€75 Microsoft hosting, €1 domain.
Weekly Workload
0-1 hour
Reasons for Selling
We are essentially a game development and custom software studio. The project went live at the end of 2025 and works so well that we prefer it for our own accounting over mid-tier solutions like LexOffice. However, to scale and fund the development of our games for the next 12–24 months, we need resources. Therefore we are selling this "nice-to-have" portfolio asset. Furthermore, we simply do not have the target audience and the intent to drive the marketing forward here. The project is being sold as a "Clean Slate". The existing database (currently 2 free and 2 paid users) will be reset to zero for legal protection. You are acquiring the pure, clean technology.
Marketing Channels
SEO
Markets
Germany
Target Group
Side businesses, small and micro-enterprises that do not want to afford bloated invoicing and/or ERP software or would simply find it too complex.
Monetization
Subscription for use
Monthly Costs
€75 Microsoft hosting, €1 domain.
Weekly Workload
0-1 hour
Reasons for Selling
We are essentially a game development and custom software studio. The app went live at the end of 2025 and works so well that we prefer it for our own accounting over mid-tier solutions like LexOffice. However, to scale and fund the development of our games for the next 12-24 months, we need resources. Therefore we are selling this "nice-to-have" portfolio asset. Furthermore, we simply do not have the target audience and the intent to drive the marketing forward here. The project is being sold as a "Clean Slate". The existing database (currently 2 free and 2 paid users) will be reset to zero for legal protection. You are acquiring the pure, clean technology.
Launch date
October 2025
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- Published on 03.04.2026
- Seller last active this week