Agency Cash Collection (n8n template)

An n8n template for agencies and freelancers who spend too long chasing unpaid invoices.

Every morning it looks at your open invoices and, for each one that is overdue:

1. Picks the right reminder: 7, 14 or 30 days after the due date (you can change the days). The last one is worded as a final notice.

2. Has Google Gemini write a short, polite reminder in your voice.

3. Checks the draft in code. Amounts, dates, links and threats are not allowed in the AI text. If the draft breaks a rule it is asked again, and if it still does, a plain template is used and you are told.

4. Emails the draft to you with Send, Edit, Don't send and Already paid buttons. Nothing goes to the client until you confirm.

5. Sends the email through Resend (or Gmail) with the amount, due date and pay link added by code from your invoice data, never from the AI.

6. Logs every reminder in an n8n Data Table, so nothing is sent twice and reminders stop as soon as the invoice is paid.

It also includes:

- Failed Stripe payments. A Stripe webhook checks the signature, emails you the amount and Stripe's next retry date, logs the attempt and drafts a short "please update your card" email for your approval. When the invoice is paid you get a "Recovered" note and the reminders stop.

- A monthly cash report on the 1st: collected and invoiced last month, outstanding and overdue now, overdue by age, the most overdue invoices, average days to pay, and what the reminders cost in AI. Every number is computed in code and checked again before the email is sent, with a CSV of open invoices attached.

Details that save you trouble

- Invoice sources: a CSV link (for example a published sheet or an export from your invoicing tool), Stripe invoices, invoices pushed to a webhook, or Google Sheets.

- Quiet hours and weekends: if you approve at night, the email waits and goes out in business hours.

- Limits: most drafts per run, most reminders per invoice, days between reminders, a minimum amount, and clients to skip.

- Approval links carry a one-time key and open a confirm page first, so a mail scanner that opens links cannot send anything.

- Sample data mode with 11 made-up invoices, so you can try the whole flow before connecting your own data. Sample emails only go to you.

- A test switch that sends every client email to you instead.

- Every setting is checked before a run. A typo stops the run with a list of what to fix, and the error workflow emails you what failed and what to do next.

- If the default Gemini model is busy, a second model is tried, then a template, so a reminder is never blocked by an AI outage.

- No API keys inside the workflow files. They stay in n8n credentials.

- In our live test one AI draft cost under one US cent. Your providers bill you directly.

What I tested and what I didn't

Tested on self-hosted n8n 2.44.6:

- 52 unit checks on the code inside the workflows, all passing.

- An automated suite of 22 scenarios with 81 checks, all passing. It runs the real workflows inside n8n with Gemini, Resend, the CSV host and the Stripe API replaced by mocks. It covers approve, edit, reject, already paid, a changed approval key, expiry, re-runs, an invoice paid while waiting for approval, limits, quiet hours, the draft check catching an invented amount, the template fallback, the backup model, CSV, pushed and Stripe sources, webhook security, bad settings, the Stripe failed and paid events, the monthly report and an unverified sender domain.

- A live run with real Gemini and real Resend on sample invoices, sent only to our own inbox: the approval email, the confirm page, the client reminder, a payment-failed alert, the payment-update draft and the monthly report all arrived. The default model was overloaded that day, so the backup model wrote both drafts.

Not tested yet:

- A real Stripe account. The Stripe parts were tested only with events built in Stripe's format and signed the way Stripe signs them, and with a stand-in for the Stripe API. A real account could still behave differently.

- The Google Sheets source and Gmail sending (these nodes ship switched off).

- The default Gemini model end to end (it was overloaded on test day), and models from other providers.

- Approving from a phone or another computer. This needs your n8n on a public HTTPS address. Our tests ran on a local instance.

- Company email security tools in real use. A link that is only opened sends nothing, but this was simulated, not tested with a real scanner.

- The real 72 hour approval expiry and multi-day quiet hours waits (shortened in tests).

- Reminders in languages other than English, and currencies other than US dollars.

- n8n Cloud, other n8n versions and queue mode with several workers.

The full test report is in the TEST-REPORT file inside the download.

Requirements

- n8n with Data Tables. Built and tested on self-hosted 2.44.6. n8n Cloud has not been tested.

- A Gemini API key from Google AI Studio.

- Resend with a verified domain, or a Gmail account.

- Your invoices as a CSV link, in Stripe, in Google Sheets, or sent to a webhook.

- Optional: a Stripe account for the Stripe source and failed-payment alerts.

- For approval links that work from your phone or inbox: n8n reachable at a public HTTPS address.

- Your own accounts with these providers. Their usage fees are billed to you by them.

Included files

- 6 workflow files (cash-1 to cash-6, JSON): settings and invoices, overdue reminders, per-reminder, Stripe failed payments, monthly digest, error handler

- README setup guide with every setting explained

- TESTING guide: a 5 minute check

- TEST-REPORT: what was tested and how

- LICENSE file

- Screenshots

Good to know

- Setup takes about 20 minutes.

- You approve every reminder by default. You can turn approval off, but we do not recommend it.

- Client names, invoice numbers, amounts and dates are sent to Gemini to write the drafts. Client email addresses are not.

- English by default. You can set another language and tone in Config (not tested in other languages).

- This template sends reminders. It does not give legal or collections advice.

License, refunds and support

This is a downloadable, self-serve software template, not a service. You import it into your own n8n and run it on your own accounts. VNCNT Labs does not host it and has no access to your data.

License: single account. Use it in your own n8n instances and in instances you run for your clients. Do not resell or redistribute the template files. Full terms are in the LICENSE file.

Refunds within 14 days, see vncntlabs.com/refund.

Questions: hello@vncntlabs.com

Sold by FAMVII LLC dba VNCNT Labs. Stripe, Google Sheets, Gemini, Resend, Gmail and n8n are trademarks of their owners. VNCNT Labs is not affiliated with them.