How to Automate Invoice Chasing with AI

By Rob Keast | Published March 2026

The Quick Answer

You can automate invoice chasing using an automation platform—such as n8n, Zapier, or Make—connected to your accounting software, with AI writing personalised follow-up emails. The workflow triggers when an invoice falls overdue, AI drafts a polite, professional follow-up, and the system sends it automatically. After each reminder, the tone escalates slightly. The setup takes 2–4 hours and saves you 3–5 hours of manual chasing every week.

The key is combining three layers: your accounting software (which knows when invoices are overdue), an automation platform (which orchestrates the workflow), and an AI model (which writes emails that sound human, not robotic). Once configured, you'll spend just minutes reviewing escalations instead of hours chasing individually.

Why Manual Invoice Chasing Fails

Most business owners chase invoices manually. It's awkward. You send one email, nothing happens. You wait a week. You send another, apologising for the repeated contact. It gets deprioritised against client work. Some invoices slip through the cracks altogether.

Manual chasing is inconsistent. You might chase one customer aggressively and another gently, depending on your mood or relationship. Your tone varies. Your timing is erratic. Customers don't take you seriously because they sense the friction.

Worse, it wastes hours. You're checking which invoices are overdue, composing emails, tracking responses, escalating when needed. That's cognitive work that drains energy from building your business.

The Automated Workflow: Step by Step

Here's how a professional automated system works:

  1. Trigger: Your accounting software detects an invoice that's overdue by, say, 3 days.
  2. AI drafts: The automation platform calls an AI model (OpenAI, Anthropic, or similar) with your customer's name, invoice amount, and due date. The AI writes a brief, polite follow-up email.
  3. Send: The system sends the email via your email provider (Gmail, Outlook, or a transactional service like Mailgun).
  4. Wait and escalate: After 7 more days with no payment, the system sends a second email with a slightly firmer tone. After 14 days, it escalates further. After 21 days, it alerts you directly because human intervention is needed.
  5. Payment received: When the customer pays, your accounting software marks the invoice as paid, and the automation chain stops.

The beauty is consistency and speed. Every customer gets the same sequence. The tone is professional. The timing is predictable. You're alerted only when you need to step in.

What You'll Need

Three layers of technology:

You'll also need:

Example Email Sequence

Day 3: Friendly Reminder

Subject: Quick reminder – Invoice #1234 now due

Hi [Customer Name],

Just wanted to flag that Invoice #1234 for £[amount] reached its due date on [date]. Could you process payment when you get a chance? If there's anything unclear on the invoice, let me know.

Cheers, [Your Name]

Day 10: Polite Escalation

Subject: Invoice #1234 – payment now overdue

Hi [Customer Name],

Invoice #1234 (£[amount]) is now 10 days overdue. We'd appreciate payment as soon as possible. If there's a dispute or issue, please let us know straightaway.

Best, [Your Name]

Day 17: Firm Reminder

Subject: URGENT: Invoice #1234 requires payment

Hi [Customer Name],

Invoice #1234 remains unpaid (now 17 days overdue). We need settlement by [date]. If there are issues, contact us immediately.

[Your Name]

Day 21+: Alert to You

System triggers an alert in your inbox: "Invoice #1234 from [Customer Name] still unpaid after 21 days. Consider payment plan negotiation or collections action."

How This Works with Specific Accounting Software

Xero

Xero has excellent API documentation. You can query invoices with status 'SUBMITTED' and due date in the past. Zapier and Make both support Xero natively, so you can set up the automation without writing code. AI email drafting happens in the automation layer. Send emails via Mailgun or your mail server.

QuickBooks Online

QuickBooks API is less intuitive than Xero's, but it's powerful. You can filter invoices by due date and status. n8n integrates well here; Zapier and Make also support it. The same email sequencing applies.

Sage

Sage (Sage Intacct) has a solid API. The setup is slightly more involved, but the workflow is identical: query overdue invoices, trigger AI-drafted emails, escalate over time.

Frequently Asked Questions

How long does it take to set up?

Most setups take 2–4 hours depending on your accounting software and the complexity of your automation rules. You'll need to map your invoice fields, define escalation rules, and write your email templates. Once configured, the system runs automatically.

Can automation handle exceptions and disputes?

Automation is excellent for routine follow-ups, but it should alert you when disputes arise or customers have valid reasons for non-payment. Your system should flag invoices tagged with 'dispute' or 'under review' and route these to your inbox for manual handling.

Which accounting software integrates best?

Xero, QuickBooks, and Sage all integrate well with n8n, Zapier, and Make. Xero is particularly straightforward because it has good API documentation. Check your platform's integrations before you commit.

Stop Chasing Invoices Manually

Automation paired with AI handles the repetitive work. You stay in control. Ready to reclaim those hours?

Book a Close The Gap AI Session and we'll map out your specific workflow.

Or check out the How Far Behind Am I? quiz to understand your cash flow gaps.

Last updated: March 2026 | Back to Guides