The verdict in three sentences
A client portal with billing and project tracking for a Dublin agency costs between EUR 20,000 and 45,000 in 2026, delivered in 3 to 4 months. Stripe/GoCardless connection and automated reminders are included and hit the crux directly: cash flow. Measurable result: DSO cut by 15-30% and an MVP at EUR 12,000 that validates adoption in 6-8 weeks.
What a client portal costs in 2026
Cost depends on how tightly project tracking couples with online payment. 2026 orders of magnitude.
| Scope | Key functions | Cost | Timeline |
|---|---|---|---|
| MVP | Project tracking, documents, login | EUR 12,000-18,000 | 6-8 wks |
| Standard | + invoices, online payment, reminders | EUR 20,000-32,000 | 3 months |
| Advanced | + deliverable approval, e-signature, notifs | EUR 32,000-45,000 | 3-4 months |
| Custom | + multi-currency, accounting API, team portal | EUR 45,000+ | 4-5 months |
Maintenance (TMA) runs EUR 200-400/month for a standard portal.
The cash lever: DSO and reminders
The real ROI of an agency client portal is faster invoice payment. Here is the effect of automated reminders on DSO (average days to pay).
| Lever | Effect on DSO | Integration cost |
|---|---|---|
| Invoice visible online | -5 to -10% | Included standard |
| Automated email reminders | -8 to -15% | +EUR 2,000-4,000 |
| Online payment (Stripe/card) | -10 to -20% | +EUR 3,000-6,000 |
| Direct debit (GoCardless SEPA) | -15 to -25% | +EUR 3,000-5,000 |
| Payment plan / split payment | -5 to -12% | +EUR 4,000-8,000 |
Mini case study
Sophie, co-founder of a communications agency in Dublin (18 staff), invoices EUR 220,000/month with an average DSO of 52 days. Each DSO day ties up roughly EUR 7,300 of cash.
She invests EUR 28,000 in a client portal with online invoices, Stripe payment and automated reminders, delivered in 3 months. DSO drops from 52 to 40 days (-23%), permanently freeing around EUR 88,000 of cash. On top, the 3 h/week spent chasing payments manually disappears (~150 h/year saved). The investment is covered in year one by the cash and time gains alone.
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
FAQ
How is this different from a plain invoicing tool?
An invoicing tool (Pennylane, Xero type) handles your invoices; a custom client portal adds project tracking, deliverable approval and a branded experience. Custom is justified when the client relationship is core to your offer.
Stripe or GoCardless?
Stripe for card payment (instant, ideal one-off); GoCardless for SEPA direct debit (ideal recurring, lower fees). Many agencies integrate both depending on invoice type.
How do reminders reduce DSO?
By automatically sending reminders at D-3, D+1, D+7 with a direct payment link. This removes forgetfulness and the "how do I pay" friction, cutting DSO by 15-30%.
Is an MVP at EUR 12,000 enough?
To validate usage (project tracking + documents), yes. You then add invoices and payment once adoption is confirmed, avoiding over-investing too early.
Can you connect my accounting software?
Yes, via API (Pennylane, Xero, QuickBooks). Budget EUR 3,000-6,000 depending on API richness and the desired sync direction.
Let's scope your project. Tell us your monthly invoicing volume, current DSO and your accounting/payment tools. 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.
