Automating invoicing and dunning with n8n vs Make: cost for a London SME (2026)

The verdict in three sentences

For a services SME, automating invoicing and dunning is one of the fastest-payback automation projects, often under 6 months. The 2026 budget is GBP 2,500 to 7,000 to set up, then around GBP 35 a month for self-hosted n8n or USD 10 to 30 a month (GBP 8 to 24) for Make. The real lever is a reminder at the right moment on the channel the client actually reads, paired with a one-click payment link.

Why overdue invoices pile up in SMEs

The pattern is common in consultancies, maintenance firms, agencies and IT providers: invoices go out late because they wait for manual sign-off, reminders are sent when the bookkeeper has time, and many clients only pay after the managing director calls. The result is a DSO (days sales outstanding) of 70 to 90 days against stated 30-day terms. The UK Late Payment Act lets you charge statutory interest, but few SMEs dare to apply it without a structured process.

Well-designed automation chains the steps with no manual work: invoice generated from the accepted quote or timesheet, sent immediately by email with a PDF, polite reminder at D-3, email chaser at D+7, then SMS or WhatsApp at D+15 with a payment link, alert to the account manager at D+30 and a formal letter drafted at D+45.

n8n or Make: which tool to choose

Under UK GDPR, self-hosted n8n simplifies compliance since billing data never leaves your infrastructure. Make remains a good choice to start quickly when volumes are modest.

Setup budget and timeline

Setup takes 3 to 5 weeks. Budget for messaging too: around GBP 0.03 to 0.05 per business-initiated WhatsApp conversation and GBP 0.04 per SMS, a few tens of pounds a month for an SME.

Mini case study

Charlotte, finance director of a 60-person IT services firm in London, carries GBP 180,000 of invoices more than 60 days overdue on monthly revenue of GBP 220,000. Her DSO is 82 days. After a full n8n automation costing GBP 5,200, DSO falls by 20 days, freeing roughly 220,000 / 30 x 20 = GBP 146,000 of cash. At an overdraft cost of 9 % a year, the financing saving alone reaches about GBP 13,000 a year, before counting the 2 days a week her credit controller spent chasing. The project pays back in under 6 months. A Dakar firm running the same playbook in FCFA (1.5 to 4 million FCFA setup) sees a comparable payback.

FAQ

Won't clients resent automated reminders?

Not if the tone is courteous and the schedule progressive. In practice, 60 to 70 % of late payments are simple oversights, and a D-3 reminder is often enough to get paid on time.

Can a payment link go in the reminder?

Yes. Stripe, GoCardless and similar providers generate a link per invoice; the paid status flows back automatically and stops the reminders.

Is n8n reliable in production?

Yes, with daily backups and monitoring. Expect around GBP 35 a month for the server and 2 to 4 hours of maintenance per quarter.

Do we need new invoicing software?

No. Xero, Sage, QuickBooks or even a structured spreadsheet can be connected. The connection accounts for GBP 650 to 1,500 of the budget.

How long before DSO improves?

First effects appear in the first billing cycle; the 15 to 25 day gain is usually measurable after 3 months.

Let's scope your project. Tell us your invoice volume and current tool, and we will price an automation between GBP 2,500 and 7,000, live in 3 to 5 weeks. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.