The verdict in three sentences
For a services SME issuing fewer than 600 invoices a month, n8n or Make connected to the existing invoicing tool is enough to automate reminders for 3,000 to 8,000 EUR of setup. A custom build, between 12,000 and 25,000 EUR, pays off once dunning rules depend on the contract, the client or a line-of-business ERP. Either way, the project should be ready for mandatory structured e-invoicing, which Ireland is phasing in for B2B from November 2028 under the EU ViDA package, or it will need rebuilding.
What a 68-day DSO really costs
A DSO (days sales outstanding) of 68 days on 6 MEUR of revenue ties up about 1.1 MEUR of cash. Getting back to 45 days frees roughly 380,000 EUR of working capital, which at a 5 % short-term financing cost means about 19,000 EUR of interest avoided each year. Then there is the finance team's time: 200 manual reminders at 6 minutes each add up to 20 hours a month.
| Indicator | Before automation | After automation (2026 estimate) |
|---|---|---|
| Average DSO | 68 days | 45 days |
| Reminders sent by hand | 200 a month | 15 to 25 a month (disputed cases) |
| Finance time spent on dunning | 20 h a month | 3 to 4 h a month |
| Invoices sent late | 12 % | under 2 % |
| Cash tied up (6 MEUR revenue) | 1.1 MEUR | 0.74 MEUR |
| Financing cost avoided | 0 | about 19,000 EUR a year |
n8n, Make or custom: the cost comparison
All three options can send a D-3, D+7, D+15, D+30 sequence with a statement of account. The difference lies in data hosting, rule complexity and maintenance.
| Criterion | Make | n8n (self-hosted in the EU) | Custom build |
|---|---|---|---|
| Subscription | 20 to 100 EUR a month | 0 to 60 EUR a month + server 15 to 40 EUR | hosting 30 to 80 EUR a month |
| Initial setup | 3,000 to 6,000 EUR | 4,000 to 8,000 EUR | 12,000 to 25,000 EUR |
| Time to go live | 2 to 3 weeks | 3 to 4 weeks | 6 to 10 weeks |
| Contract-specific dunning rules | limited | good with JS code | unlimited |
| Data hosting | Make cloud (EU available) | your servers in Ireland or the EU | your servers in Ireland or the EU |
| Link to Xero, Sage, QuickBooks | native connectors | API or HTTP | dedicated API |
| Annual maintenance | 1,000 to 2,000 EUR | 1,500 to 3,000 EUR | 2,500 to 5,000 EUR |
Our recommendation: Make for an SME under 300 invoices a month without a line-of-business ERP, self-hosted n8n as soon as IT requires data to stay in the EU, custom if reminders must account for project milestones, partial credit notes or a client portal.
E-invoicing: the timeline that shapes the brief
The EU ViDA package makes structured e-invoicing the norm for intra-EU B2B trade by July 2030, and Irish Revenue has announced a phased domestic rollout starting November 2028. Your automation should therefore read invoice status (delivered, rejected, paid) from a Peppol access point rather than relying on e-mail alone.
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| Deadline | Obligation | Impact on automation |
|---|---|---|
| Today | Peppol e-invoices accepted by Irish public bodies | connect a Peppol access point |
| Nov. 2028 | Phase 1: large corporates exchanging B2B e-invoices | corporate clients expect structured invoices |
| Nov. 2029 | Phase 2: wider B2B scope including SMEs trading intra-EU | dunning relies on network status |
| July 2030 | ViDA: digital reporting for intra-EU transactions | automatic export of invoice data |
| Ongoing | Late Payment Directive: statutory interest at ECB rate + 8 % | automatic interest calculation in reminders |
Mini case study
Siobhan, CFO of a Dublin IT services firm (45 staff, 6 MEUR revenue, 420 invoices a month), picks self-hosted n8n connected to Xero and a Peppol access point. Setup: 6,500 EUR, server and maintenance: 2,400 EUR a year. First-year gains: 17 hours a month recovered at 45 EUR loaded cost, i.e. 9,180 EUR, plus 19,000 EUR of financing costs avoided with DSO down to 47 days. The project pays back in under 4 months.
FAQ
Won't automated reminders damage client relationships? Tone is set per segment: polite at D+7, firm at D+30, and the top 20 clients by volume can be excluded for a human call. In our projects, fewer than 1 % of clients react negatively to a well-written automated reminder.
Is n8n GDPR compliant? Self-hosted on a server in Ireland or elsewhere in the EU, invoicing data never leaves your infrastructure. Budget 15 to 40 EUR a month for a server sized for 1,000 executions a day.
Do we need to change invoicing software for e-invoicing? Not necessarily: Xero, Sage or QuickBooks can connect to a Peppol access point. The extra cost is often 0.10 to 0.30 EUR per invoice depending on the provider.
How long before DSO drops? First effects show within 6 to 8 weeks, the time for a full billing cycle to run through the new sequence. The 45-day target is usually reached within 4 to 6 months.
Can we add online payment to the reminder? Yes, a card or SEPA direct debit payment link cuts another 5 to 10 days. Fees range from 0.35 % to 1.5 % per transaction depending on the method.
Let's scope your project. We scope your invoicing and dunning automation (current tool, volume, e-invoicing network) with an indicative budget of 3,000 to 25,000 EUR and go-live in 2 to 10 weeks. 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.
