The choice between an in-house team and an agency can mean a EUR 100.000+ annual difference. The myth that “an agency is more expensive” does not hold up: companies that need fewer than 40 development hours per week almost always lose money on in-house once you factor in hidden costs. In-house only becomes rational at 80+ hours per week with a clear long-term technical vision.
Real annual cost per senior developer
Annual all-in cost in the region - far above the headline salary:
| Cost item | Yearly range (EUR) |
|---|---|
| Net salary | 24.000 - 48.000 |
| Taxes and contributions | 18.000 - 36.000 |
| Hardware, software, training | 4.800 - 12.000 |
| Office, bonuses, benefits | 4.800 - 12.000 |
| HR and leadership overhead | 6.000 - 36.000 |
| Total all-in | 60.000 - 130.000 |
Plus turnover risk: resignations, vacation, parental leave. Compare with typical custom software cost in Croatia.
What an agency actually costs
Same senior caliber, different model: EUR 60 to EUR 90 per hour, monthly retainer EUR 6.000 to EUR 12.000 full-time, fixed-price projects EUR 5.000 to EUR 80.000+. Included: senior dev, PM, QA, DevOps, designer, backup developer, hardware. Part-time (20-40 hours): EUR 2.500 to EUR 6.000 per month.
When each model wins
- Under 20 hours per week: Agency. Part-time senior hires are unrealistic; an MVP in 12 weeks usually beats hiring.
- 20 to 40 hours per week: Agency usually wins. Optionally junior in-house plus agency seniors.
- 40 to 80 hours per week: Mixed. In-house pays off only if you can staff all roles.
- 80+ hours per week: In-house becomes serious. Even then, agencies cover niche work.
Hybrid models that often win
Technical partner: one or two internal developers own business context; agency handles everything larger. Best for SMBs of 50 to 200 employees; annual cost EUR 100.000 to EUR 250.000. Build and transfer: agency builds MVP and early versions, transfers knowledge over a year or two, in-house team takes over. Best for startups; first-year cost EUR 120.000 to EUR 200.000, decreasing afterwards.
Common mistakes
Hiring juniors without a senior lead piles up technical debt. Picking on hourly rate alone - EUR 15 per hour offshore often costs more than EUR 70 per hour EU work because of rework - is one of the classic digitalization mistakes. Treating the agency as second-tier destroys architectural coherence. Skipping documentation makes both directions of handover painful.
Frequently Asked Questions
We do EUR 3M in revenue - do we need our own dev team? Depends on how much value software creates. If software is the product (SaaS), yes. If it supports the business, an agency is usually enough.
What if the agency leaves and we are stuck? A real partner signs a handover clause: code in your repo, documentation accessible, two- to four-week transition. The 12 selection questions determine how painful this gets.
Can we embed an agency senior in our team? Yes. Many agencies offer “embedded developer” arrangements for EUR 8.000 to EUR 15.000 per month.
Who owns architecture in a hybrid model? Agency Tech Lead plus one senior in-house developer, decisions made jointly. Without clear ownership, architecture drifts.
Related Articles
- How to choose a development agency - the 12 questions that reveal a real partner.
- Custom software vs SaaS - when each model pays off.
- Custom software cost in Croatia - budget ranges to validate build-vs-hire math.
Thinking about your software approach?
Book a free Discovery call. We review your stage and propose a model that pays off operationally over the next two to three years. Reach us at [email protected] or via the form on our homepage.