The verdict in three sentences
Above 300 to 500 monthly contracts, manual billing becomes the main brake on a service company's growth: proration errors, forgotten reminders, late collections. There are two routes: a SaaS tool charging 0.5% to 1% of revenue, quick to deploy, or a custom platform at EUR 25,000 to 50,000 excl. VAT when your contracts do not fit standard boxes. Either way, SEPA direct debit and automated dunning cut involuntary churn by about 30%, and European e-invoicing mandates make the project urgent.
SaaS or custom: the numbers
| Criterion | Recurring billing SaaS | Custom platform |
|---|---|---|
| Entry cost | EUR 0 to 5,000 setup | EUR 25,000 to 50,000 |
| Recurring cost | 0.5% to 1% of billed revenue, or flat fee | EUR 300 to 900/month (hosting, maintenance) |
| Time to go live | 2 to 6 weeks | 2 to 3 months |
| Non-standard contracts (tiers, usage, multi-site) | partly, via workarounds | fully |
| ERP and CRM integration | off-the-shelf connectors | custom, close to your processes |
| Vendor dependency | high (data, pricing) | low (your code and data) |
| Economic tipping point | up to EUR 3M to 5M recurring revenue | above EUR 3M to 5M, or unusual pricing model |
The maths is simple: at 1% of EUR 4M billed per year, SaaS costs EUR 40,000 a year, every year. A EUR 40,000 platform plus EUR 7,200 annual maintenance becomes cheaper from year two.
Must-have features in 2026
| Feature | What it fixes | Observed gain (ballpark) |
|---|---|---|
| SEPA direct debit (e-mandate) | collection on a fixed date, no chasing | DSO down from 45 to 10 days |
| Automatic proration | plan changes mid-month | zero manual calculation errors |
| Graduated dunning (D+3, D+10, D+20) | forgotten unpaid invoices | 40% to 60% of unpaid invoices recovered without a call |
| Smart retry of rejected debits | insufficient funds rejections | involuntary churn down about 30% |
| E-invoicing (Factur-X / Peppol, certified platform) | compliance with 2026-2028 mandates | avoids per-invoice penalties (EUR 15 in France) |
| Customer portal (invoices, mandate, payment method) | billing support requests | 50% fewer billing tickets |
On e-invoicing: since 1 September 2026, every French company must be able to receive e-invoices, issuing becomes mandatory for SMEs and micro-businesses on 1 September 2027, and Belgium, Germany and other EU states are rolling out similar B2B mandates. Your platform must output structured invoices and transmit them through a certified platform or Peppol access point. In a custom project, the connector usually costs EUR 3,000 to 6,000.
Mini case study
Marc runs an IT maintenance company in Bordeaux and invoices 900 monthly contracts averaging EUR 380, i.e. EUR 342,000 a month. Two people spend 8 days a month issuing, sending and chasing invoices, and 4% of customers leave each year because payment fails (expired card, rejected debit). He chooses a custom platform for EUR 38,000, delivered in 10 weeks. Involuntary churn falls by 30%: 4% x 0.3 = 1.2 points, about 11 customers retained per year, so 11 x EUR 380 x 12 = EUR 50,160 of annual revenue preserved. Add 12 working days freed each month. The platform pays back in under a year.
FAQ
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
Is SEPA direct debit suitable for business customers?
Yes, with the SEPA B2B or CORE mandate. B2B prevents the customer from disputing after debit, which secures collection, but the customer's bank must register the mandate.
How does e-invoicing work in a custom platform?
The platform generates Factur-X or Peppol invoices and sends them to a certified platform. The connector costs EUR 3,000 to 6,000 and protects you from per-invoice non-compliance penalties.
How are mid-month plan changes handled?
The engine calculates proration to the day and adds it to the next invoice or issues a credit note. On 900 contracts, that removes 20 to 40 manual corrections a month on average.
How long to migrate 900 contracts?
Allow 2 to 3 months in total, including 2 to 3 weeks to import contracts and collect SEPA mandates. Old and new systems run in parallel for one billing cycle.
Does involuntary churn really fall by 30%?
It is an observed ballpark when scheduled retries, email reminders and self-service payment method updates are combined. The result depends on your starting rejection rate.
Let's scope your project. Tell us your contract count, plans and accounting tool: we will compare SaaS and custom, then quote a platform between EUR 25,000 and 50,000 delivered in 2 to 3 months. 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.
