← Billing & Invoicing

Build it yourself

Implementation instructions

Everything here is meant to be genuinely actionable—hand it to yourself, a developer, or your own AI coding tool. Nothing is held back to push you toward hiring us.

Setup checklist

  • 1.Confirm your invoicing tool has an API or Zapier/n8n integration
  • 2.Define your reminder schedule (e.g. day 3, day 10, then human)

Implementation sequence

  • 1.Trigger invoice generation from milestone completion or a recurring schedule
  • 2.Sync payment status from your processor automatically
  • 3.Send reminder 1 at day 3 overdue, reminder 2 at day 10, then notify you directly

Architecture

  • Trigger → generate invoice → track status via webhook → reminder sequence

AI instructions

Claude/ChatGPT instructions for the firmer follow-up

Instructions / Skill content

Write a polite but direct follow-up for an invoice that is [X] days overdue. Reference the invoice number and amount. No guilt-tripping, no excessive apology—state the facts and ask for a payment date.

Automation logic

Invoice, tracking, and reminder cadence

  1. 1.On milestone/schedule: generate invoice from contract terms, send
  2. 2.On payment webhook: mark paid, cancel any pending reminders
  3. 3.On day 3 unpaid: send reminder 1
  4. 4.On day 10 unpaid: send reminder 2 and notify owner

Integration instructions

  • 1.Payment processor webhook for payment-succeeded
  • 2.Invoicing tool API for generation

Testing procedures

  • 1.Run a sandbox invoice through the full cycle including a simulated non-payment

Failure handling

  • 1.If the payment webhook is missed, reconcile daily against the processor's own report

Maintenance checklist

  • 1.Review reminder tone and timing after the first quarter of real use

Ready-to-use prompts

Paste these into Claude, ChatGPT, Cursor, or Claude Code to get started immediately.

Claude / ChatGPT prompt

Create a saved prompt 'Overdue Invoice Follow-up' using the instructions above.

Cursor / Claude Code prompt

Build an n8n workflow: Schedule/Milestone Trigger → generate invoice via [INVOICING TOOL] API → Payment Webhook listener → conditional reminder sends at day 3 and day 10.

n8n workflow design

Trigger → Generate Invoice → Webhook Listener → Wait/Check → Reminder Send

Rather have us build it?

Same system, no extra discovery call—we already know the scope.

Have Workflowr Build This