The verdict in three sentences
A custom subscription and membership web app costs EUR 35,000 to EUR 80,000 in 2026 and ships in 4 to 6 months. It drives billing cycles, dunning (retrying failed payments) and payment/accounting integration. Custom is justified as soon as your subscription model falls outside a billing SaaS's standards.
Scope and cost by module
| Module | Content | Cost (2026 estimate) |
|---|---|---|
| Cycle management | Plans, proration, upgrade/downgrade | EUR 10,000 - 22,000 |
| Recurring billing | Invoice generation, VAT, credit notes | EUR 8,000 - 18,000 |
| Dunning / retries | Auto retry, emails, SMS, suspension | EUR 6,000 - 14,000 |
| Member portal | Self-service, payment methods | EUR 5,000 - 12,000 |
| Accounting integration | Export, reconciliation, API | EUR 4,000 - 10,000 |
| Reporting | MRR, churn, collections, cohorts | EUR 4,000 - 9,000 |
Dunning is the best value-for-cost module: it recovers revenue already earned but blocked by expired or declined cards.
Custom build vs billing SaaS
| Criterion | Billing SaaS (Chargebee/Stripe Billing type) | Custom app |
|---|---|---|
| Recurring cost | 0.5 - 0.9% of collected revenue | Hosting EUR 150-500/month |
| Supported models | Standard | Custom (hybrid, a la carte) |
| Member portal | Generic | Branded, own journeys |
| Local accounting | Add-ons | Native |
| Data ownership | Shared | Full |
| Pays off if | < EUR 500,000 recurring revenue | High revenue, specific model |
At EUR 2,000,000 recurring revenue, a SaaS at 0.7% costs ~EUR 14,000/year; beyond that, custom amortises fast while offering more flexibility.
The hidden cost of failed payments
| Annual recurring revenue | Failures without dunning (~7%) | Recovered with dunning (~70% of failures) |
|---|---|---|
| EUR 500,000 | ~EUR 35,000 lost | ~EUR 24,500 recovered |
| EUR 1,000,000 | ~EUR 70,000 lost | ~EUR 49,000 recovered |
| EUR 2,000,000 | ~EUR 140,000 lost | ~EUR 98,000 recovered |
| EUR 3,000,000 | ~EUR 210,000 lost | ~EUR 147,000 recovered |
Involuntary failures (expired cards, limits) often represent 5 to 8% of recurring revenue. Well-tuned dunning recovers 60 to 75% of them.
Mini case study
Julie, CFO of a recurring-services firm in Amsterdam, manages EUR 1,200,000 in annual subscription revenue. Before, ~7% of revenue (~EUR 84,000) was lost to un-retried failed payments. She invests EUR 58,000 in an app with automatic dunning and a member portal. The system recovers ~70% of failures, i.e. ~EUR 59,000 in year one. The investment is nearly repaid in the first year through cash recovery alone, before administrative time savings.
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
FAQ
What exactly is dunning?
It's the automatic retrying of failed payments: scheduled new attempts, card-update emails and SMS, then gradual suspension. Well tuned, it recovers the majority of involuntary failures.
Do we need a self-service member portal?
Yes: letting customers update their card, change plan or download invoices reduces support and improves retention.
When does custom beat a billing SaaS?
When your model is atypical (hybrid pricing, commitments, quotas) or when your recurring revenue makes the SaaS percentage costlier than the build.
How do we handle VAT and local accounting?
The app generates compliant invoices and exports to your accounting tool. Plan this integration scope at kickoff.
Which metric should we watch first?
Churn and the failed-payment recovery rate. They directly drive your net MRR and cash flow.
Let's scope your project. Give us your recurring revenue, subscription model and accounting integrations, and we'll price your app. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
