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Case Study: Generating Invoices with Cassiopeia API


Let's say you have a mid-sized software company and let's call it "Tech Solutions Inc.". You need to generate and send ca. 5,000 invoices as PDFs to your clients. You have two options now: develop an in-house solution for the PDF generation or integrate with the Cassiopeia API.

In-House Implementation


  • Development of a PDF generation pipeline.
  • Handling all the nasty edge cases, font rendering, compression and other issues.
  • Implement variable data insertion (e.g., client name, invoice amount).
  • Ensuring scalability and reliability.
  • Maintenance, Bugfixes and updates.

Costs and Effort:

  • Development Time: Estimated 2-3 months.
  • Developer Costs: Assuming an average developer salary of 80,000€/year, the cost for 2-4 months would be approximately 13,000€-20,000€.
  • Maintenance: Ongoing costs for bug fixes, updates, and improvements, estimated at 5,000€/year.
  • Infrastructure: Costs for higher server capacity, estimated at 500€/year.
  • Total First-Year Cost: 18,500€-25,500€ (development + maintenance + infrastructure).

Cassiopeia API Integration


  • Simple RESTful API for PDF generation.
  • Support for variables and document merging.
  • Scalable and reliable service.
  • No additional infrastructure required.
  • Minimum maintenance requirements.


  • Conqueror Plan: €45/month flat fee, including 500 free requests.
  • Additional Requests: €0.005 per request.
  • Integration of the Cassiopeia API with testing and deployment: Estimated at 5 days = ~1,700€.

Example Calculation:

  • Initial integration cost: 1,700€
  • Monthly Requests: 5,000 (500 free + 4500 paid)
  • Monthly Cost: 45€ (flat fee) + (4500 * 0.005€) = 67,50€
  • Annual Cost: 67,50€ * 12 = €810.


AspectIn-House ImplementationCassiopeia API Integration
Development Time2-4 monthsMinimal (max. few days)
Initial Cost13,000€-20,000€€1,700€
Annual Maintenance5,000€< 1000€
ScalabilityRequires additional resourcesBuilt-in
ReliabilityDepends on internal resourcesHigh (managed service)


Integrating with the Cassiopeia API is clearly the better choice our example company "Tech Solutions Inc." The API offers a cost-effective, scalable, and reliable solution for generating invoices as PDFs. The initial and ongoing costs are significantly lower compared to developing and maintaining an in-house solution. Additionally, the ease of integration and the robust features provided by Cassiopeia ensure that the company can focus on its core business activities rather than managing PDF generation infrastructure.