# Stop chasing late invoices: an automated invoice and follow-up build Source: https://getstartedwithai.net/tutorials/invoice-followup-automation-solo Site: Get Started With AI Tagline: Build AI automations that actually run your business. Audience: solo professionals, freelancers, consultants and AI implementers in training Contact: hello@getstartedwithai.co.uk This Markdown companion is generated from the prerendered page for AI crawlers. # Stop chasing late invoices: an automated invoice and follow-up build Late-paying clients eat 5 to 15 days of cash flow per quarter for most solo professionals. The angry chase email written at 11pm is not the answer. A small Zap watches Stripe or Xero, fires a calm reminder on day 3, a firmer one on day 10, and pings you to write a personal note on day 21. Tools used: Zapier Professional, Stripe or Xero, Gmail, Slack. Build time 60 minutes. Most consultants drop their average days-to-pay by 5 to 12 days inside the first quarter, which on £25,000 monthly billings is roughly £4,000 to £10,000 of cash brought forward. ## The three-touch pattern Polite enough to keep the client. Firm enough to get paid. - Touch 1, day 3 after due: friendly nudge with the invoice link. Most invoices clear here. - Touch 2, day 10: firmer reminder with the late-fee policy attached if you have one. - Touch 3, day 21: an internal Slack escalation that lands a personal email or call into your task list. The client has gone past automation. ## What you need - An invoicing tool that triggers on issued and paid: Stripe, Xero, FreshBooks, QuickBooks or HubSpot Payments. - Zapier Professional at £16/mo annual, or Make Core at £8/mo annual. - Gmail or Outlook for the email steps. - Slack for the day-21 escalation. - 60 minutes uninterrupted. ## Step 1: Catch the invoice issued event (5 minutes) 1. In Zapier create a new Zap. Trigger: Stripe (or Xero) New Invoice Created. 2. Connect the account. Test the trigger. You should see a recent invoice with all fields visible. 3. Add a Filter step: only continue if invoice status is open (issued and waiting for payment). ## Step 2: Day-3 nudge (15 minutes) 1. After the trigger, add a Delay step. Delay Until the invoice due date plus 3 days. 2. Add a Stripe (or Xero) Find Invoice step using the invoice ID. Re-fetch the latest status. 3. Add a Filter: only continue if the status is still open (not paid). 4. Add a Gmail Send Email action. Subject: Friendly reminder: invoice {{invoice_number}}. Body: paste a calm template with amount, due date and a payment link. 5. Send a test against a real overdue invoice to confirm the email lands cleanly. ## Step 3: Day-10 firm reminder (15 minutes) 1. Add a Delay Until day 10 after the original due date. 2. Add another Stripe Find Invoice plus Filter for open status. 3. Add a Gmail Send Email action with a firmer subject ("Outstanding invoice: {{invoice_number}}") and body that mentions your late-fee policy if you have one. 4. Optional: attach the late-fee schedule PDF as a static attachment. ## Step 4: Day-21 escalation (10 minutes) 1. Add a Delay Until day 21. 2. Add the Find Invoice plus Filter for open. 3. Add a Slack Send Direct Message to yourself: Invoice {{invoice_number}} for {{client}} is now 21 days overdue. £{{amount}}. Client contact: {{client_email}}. Action: personal email or call today. 4. Optional: add a Notion or Asana Create Task step so the escalation lands in your task list rather than only Slack. ## Step 5: Add the paid-stop guard (5 minutes) This step is the one that protects you. An automation that emails a client three times after they have already paid is a relationship killer. 1. Each Delay-then-Find-then-Filter combo above must check status equals open before sending. Confirm all three filters are in place. 2. Belt-and-braces: at the start of the Zap, set a custom field on the invoice (automation-active = true). When the invoice is marked Paid in Stripe, a separate Zap clears the field, which a top-of-Zap filter checks. ## Step 6: Test against three real invoices (10 minutes) 1. Issue a test invoice to yourself with a due date 1 day in the past. 2. Force the Zap by manually shortening the delays to a few minutes. Watch each step fire. 3. Mark the test invoice paid in Stripe between Touch 1 and Touch 2. Confirm the day-10 email does not send. 4. Restore the original delays before turning the Zap on for real clients. ## What you ship A working three-touch invoice chase that runs without you opening Stripe. Most consultants see days-to-pay drop 5 to 12 days inside the first quarter. Charge clients £900 to £2,200 for the same build with a 30-day check-in. Compute their average days-to-pay before the build and again 60 days after, then put the cash-flow gain in pounds in the case study. ## Common mistakes - Forgetting the paid-stop guard. The first nag email after a paid invoice loses you the client. - Sending Touch 1 too early. Day 3 is the right balance. Day 1 reads as panicky. - Hardcoding amounts and dates instead of using variables. Variables are the whole point of the Zap. - Sending the day-21 email to the client. The escalation is internal. Land it in your Slack and write the actual email yourself. ## What to build next The natural next build is client onboarding automation, which closes the engagement loop the same way invoice followup closes the cash loop. Together they cover the two ends of the client lifecycle. ## Related builds More tutorials in Automation. Each one runs in 60 to 90 minutes and ships a finished asset. ### Capture every lead automatically: a 30-minute Zapier build 30 to 60 minutes. Solo Pro. [Open tutorial](/tutorials/first-zapier-automation-30-min) ### Decide between native AI Steps and a Custom GPT in 10 minutes 60 to 90 minutes. Solo Pro. [Open tutorial](/tutorials/zapier-ai-features-vs-custom-gpt) ### Run automations Zapier cannot: the first Make scenario 60 to 90 minutes. Solo Pro. [Open tutorial](/tutorials/first-make-scenario-visual) ### Self-host the automation stack: when n8n is worth the effort 60 to 90 minutes. Solo Pro / Implementer. [Open tutorial](/tutorials/n8n-self-hosted-when-worth-it) ## Questions people ask before they start ### What if my client is on Net 30 or Net 60 terms? Add the term length to the day-3, day-10 and day-21 timing. Net 30 means the first touch fires on day 33 from issue date. Use the invoice due date as the anchor for all delays. ### Should I include a late fee? Optional. If you charge late fees, mention the policy in Touch 2. If you do not actually charge them, do not bluff. Clients call the bluff and the relationship suffers. ### Can the automation use a different voice for different clients? Yes. Add a CRM Find Contact step at the top, read a tone field, then use a Path or Branch to pick the email template. Most solo professionals do not need this until they have 50+ active clients. ### Will Stripe trigger on Xero invoices? No, the triggers are tool-specific to each platform. If you use Xero, use the Xero trigger. If you use both, run two parallel Zaps with the same shape. ### How do I handle disputed invoices? Pause the Zap on that contact manually when the dispute opens. The cleanest method is a tag on the CRM record (paused-from-automation) checked by a top-of-Zap filter.