Purchase Approval Workflow: n8n vs Make vs Custom Cost in Dublin (2026)

The verdict in three sentences

For an SME of 50 to 150 employees, a purchase approval workflow with 3 levels based on amount cuts approval time from 6 days to 1 day and makes every spend traceable. Make is enough to start fast under 100 requests a month, self-hosted n8n is the best compromise once data must stay in a chosen jurisdiction, and custom (EUR 8,000 to 20,000 excl. VAT) is justified when the workflow must manage budgets per department and talk closely with accounting. In all three cases, most of the work is writing the approval rules, not choosing the tool.

The problem: purchase orders with no traceability

At a typical SME, a purchase request starts as an email or an Excel file, waits for a travelling manager's signature, comes back incomplete, then reaches accounting after the invoice arrives. Result: unbudgeted commitments, duplicate suppliers and no way to answer how much have we committed this month.

A digital workflow enforces a single path: request form, automatic routing by amount and department, one-click approval from a phone, reminder after 24 hours, then purchase order creation in the accounting tool (Xero, Sage, Business Central or Odoo).

n8n, Make or custom: 2026 comparison

Make's trap is per-operation billing: a workflow with reminders and attachments quickly uses 20 to 40 operations per request. Above 300 monthly requests, n8n becomes cheaper. Custom is not sturdier by principle, it is when rules change often or when requesters struggle with generic forms.

Mini case study

Isabelle, CFO of a 90-employee building materials distributor in Dublin, handles about 180 purchase requests a month. Her accounts assistant spends 2 hours a day chasing approvers and re-keying orders, 40 hours a month, about EUR 1,400 of loaded cost.

She picks self-hosted n8n with 3 approval levels, a Xero connection and new-supplier checks: EUR 5,500 excl. VAT setup and EUR 45 a month for the server. Chasing time drops to 5 hours a month, 35 hours and EUR 1,225 saved every month. Payback in under 5 months. More important to her: a duplicate EUR 7,800 invoice is blocked in month two, which alone more than covers the project.

FAQ

Do approvers need to install an app?

No. With Make or n8n, approval happens through a link in an email or a Teams or Slack message. Custom can add a mobile web app with no store install.

Can the workflow connect to Xero or Sage?

Yes. Xero and Odoo have modern APIs, and the connection takes 2 to 4 days. For an on-premise Sage install, a specific connector adds EUR 1,500 to 3,000 excl. VAT.

What happens if an approver is away?

The workflow handles automatic delegation after 24 or 48 hours to a predefined deputy. This is one of the first rules to write, and it prevents 80% of blockages.

Does self-hosted n8n require in-house IT staff?

No, but you need a maintenance contract for updates and backups, usually EUR 150 to 400 a month. Without it, n8n cloud from EUR 24 a month is the better option.

Will the workflow stand up to an audit?

Yes, every step is timestamped with the approver's identity. The exported history satisfies most auditors, provided logs are kept for the legally required period, typically 6 to 10 years.

Let's scope your project. Tell us your request volume, approval thresholds and accounting tool: we will recommend Make, n8n or custom with an indicative budget between EUR 2,500 and 20,000 excl. VAT and a go-live date. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.