Automation library · Money admin

Invoice management system with Gmail and Google Sheets

Started by another system calling it, and works across Gmail, Google Sheets and Slack. 22 steps, 1 branch, 1 loop or waits: large, and worth reading before you trust it with anything live.

Large

Download free
22 stepsLarge: read it before trusting it with anything live
1Branch: places the flow splits
1Loop or waits
3Services it connects to

The flow

Starts it 3Logic 10Service 9

The steps in the order they run, from what starts it.

  1. 1New Invoice RequestWebhookStarts it
  2. 2Daily Overdue CheckSchedule triggerStarts it
  3. 3Initialize InvoiceSetLogic
  4. 4Get Unpaid InvoicesGoogle SheetsService
  5. 5Split Line ItemsSplit OutLogic
  6. 6Calculate Overdue DaysCodeLogic
  7. 7Calculate Line TotalCodeLogic
  8. 8Loop Over InvoicesSplit In BatchesLogic
  9. 9Aggregate Line ItemsAggregateLogic
  10. 10Route by Reminder LevelSwitchLogic
  11. 11Build Invoice ObjectCodeLogic
  12. 12First Reminder EmailGmailService
  13. 13Second Reminder EmailGmailService
  14. 14Urgent Reminder EmailGmailService
  15. 15Final Notice EmailGmailService
  16. 16Escalate to CollectionsSlackService
  17. 17Save Invoice to SheetGoogle SheetsService
  18. 18Merge Reminder PathsMergeLogic
  19. 19Send Invoice EmailGmailService
  20. 20Update Reminder DateGoogle SheetsService
  21. 21Invoice Created ResponseRespond To WebhookStarts it
  22. 22Continue LoopCodeLogic

How it's built

Starts on
Another system calling it
Steps
22, with 1 branch, 1 loop or waits
Size
Large: read it before trusting it with anything live
Connects to
Gmail, Google Sheets, Slack
Model
None. This is plumbing, not judgement

Questions

What does it need to run?

An n8n account, plus your own Gmail, Google Sheets and Slack accounts. You connect your own accounts after importing it; none are included.

What starts it?

It starts on another system calling it.

Does it use AI?

No. Every step is fixed logic or a call to a service, so it does the same thing every time.

How long does it take to set up?

Take your time. At 22 steps it is large: read it before trusting it with anything live.

How do I import it?

Copy the workflow, open a new workflow in n8n and paste. The steps appear on the canvas, ready for your own accounts.

Before you run it

Nothing here has been tested by us. It is somebody's working automation, read and described from its own steps. Treat the connections it wants as a list of accounts it will touch, and read the 22 steps before you point it at anything that matters.