How to Automate Invoice and Payment Reminders with AI
Late payments are the number one cash flow killer for small businesses and agencies. This guide shows you how to build an AI-powered payment reminder system using Make.com and Xero (or QuickBooks) that sends the right message at the right time — automatically, and in a tone that preserves the client relationship.
What the Automation Sends and When
| Trigger | Message Type | Tone | Channel | Sender |
|---|---|---|---|---|
| Invoice issued | Friendly confirmation | Warm, helpful | Account manager | |
| 3 days before due | Gentle reminder | Friendly, proactive | Account manager | |
| Due date (unpaid) | Polite nudge | Professional, non-urgent | Email + optional SMS | Account manager |
| 3 days overdue | First chase | Direct but courteous | Account manager | |
| 7 days overdue | Second chase | Firm, solutions-focused | Account manager | |
| 14 days overdue | Escalation | Serious, clear next steps | Director or owner | |
| 21 days overdue | Final notice | Formal, legal reference | Director + legal template |
Step by Step
Connect Xero or QuickBooks to Make.com
In Make.com, create a new scenario. Add a Xero module: Watch Invoices. This triggers whenever an invoice status changes (created, updated, paid, overdue). Connect your Xero account using OAuth — Make.com walks you through the authentication flow. For QuickBooks, use the QuickBooks module in the same way. Test by creating a test invoice in Xero and confirming Make.com detects it. If you use a different invoicing tool, check whether it has a Make.com module or a webhook/API you can connect to the HTTP module.
Build the invoice age calculator
Add a Make.com Tools module: Set Variable. Calculate the number of days since the invoice due date: use Make.com’s date arithmetic to subtract the due date from today’s date. Store this as ‘days_overdue’ (a negative number means the invoice is not yet due; positive means it is overdue). Add a Router module after this to branch the scenario based on days_overdue value: one route for each reminder stage in your sequence table above. Each route has a filter: days_overdue equals -3 (3 days before due), equals 0 (due today), equals 3 (3 days overdue), and so on.
Generate AI-personalised reminder emails
For each route, add an HTTP module calling Claude to generate the personalised email. The prompt varies by stage — for the 3-days-overdue reminder: Write a professional payment reminder email from [sender name] at [business name] to [client contact name] at [client company]. Invoice: [invoice number] for [amount] due [due date], now 3 days overdue. Tone: direct and professional but warm — we value this client relationship and want to resolve this without friction. Do not be aggressive or threatening. Include: the specific invoice number and amount, a polite request for payment or confirmation of expected payment date, an offer to discuss if there is any issue with the invoice, and the payment link or bank details. Length: 150 words maximum. Claude generates a professional, personalised reminder that sounds like it was written by a human who cares about the relationship.
Send via Gmail or Outlook and log to CRM
Add a Gmail or Outlook module to send the generated email. Configure it to send from the account manager’s email address (not a generic billing@ address — personal sender addresses have higher open rates and preserve the relationship context). Add a GoHighLevel or CRM Update module to log the reminder sent: date, invoice number, reminder stage, and whether the email was opened (add tracking if your email platform supports it). This log gives the account manager visibility into which invoices have been chased and how many times.
Handle payment received
Add a parallel scenario triggered when invoice status changes to Paid in Xero. This scenario: cancels any pending reminder sequence for this invoice (use a Make.com data store to flag the invoice as paid, so the reminder scenarios skip it), sends a payment received confirmation to the client (a brief, warm acknowledgment), and updates the CRM with payment date. The system stops chasing once payment is received — clients never receive a reminder after they have already paid.
📌 Add a pre-send review step for any invoice over a threshold value (e.g., over $5,000) or any escalation-stage email. Rather than sending automatically, these high-stakes messages are sent to a Slack channel or email for the account manager to review and approve before delivery. Automated for routine reminders; human-controlled for sensitive escalations.
Won’t automated reminders damage client relationships?
Automated reminders damage relationships when they are impersonal, poorly timed, or sent after the client has already communicated about the invoice. The system prevents the last issue by logging all communications and pausing reminders when a client replies. For the first two issues, AI-generated reminders calibrated to the relationship stage and sent from the account manager’s address are indistinguishable from manually written ones — and more consistent than the manual alternatives, which are often either too soft (not sent at all) or too aggressive (sent in frustration when an invoice is significantly overdue).
What if a client disputes the invoice?
Build a dispute detection step: when the client replies to a reminder email, a Make.com scenario analyses the reply with Claude to detect dispute signals (mentions of incorrect amount, service not received, already paid, etc.). If dispute signals are detected, the reminder sequence is paused and an alert is sent to the account manager with the client’s reply. Disputed invoices need human resolution — the automation gets out of the way and ensures the right person is notified immediately.
Want Your Payment Reminder System Automated?
SA Solutions builds Make.com invoice automation workflows — connected to Xero, QuickBooks, or any invoicing platform — with AI-generated reminders, CRM logging, and payment tracking.
