Automation library · Money admin

Match supplier invoices to purchase orders with Gmail

Started by an arriving email, and works across Gmail and n8n data table. It hands the judgement calls to OpenAI. 19 steps, 2 branches: a working afternoon to understand properly.

MediumCalls a model: OpenAI

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19 stepsMedium: a working afternoon
2Branches: places the flow splits
0Loops or waits
2Services it connects to

The flow

Starts it 1Model 3Logic 9Service 6

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

  1. 1Watch The Invoice LabelGmail triggerStarts it
  2. 2ModelLm Chat Open AiModel
  3. 3SettingsSetLogic
  4. 4Pull Out The Invoice FieldsInformation ExtractorModel
  5. 5Write The Query To The SupplierChain LlmModel
  6. 6Keep Only The PDFsCodeLogic
  7. 7Parse The MoneyCodeLogic
  8. 8Read The QueryCodeLogic
  9. 9Is There An Invoice Attached?IfLogic
  10. 10Read The Open Purchase OrdersData TableService
  11. 11Everything In HandMergeLogic
  12. 12Log It As HeldData TableService
  13. 13Draft The Reply To The SupplierGmailService
  14. 14Read The PDFExtract From FileService
  15. 15No Invoice On This OneNo OpLogic
  16. 16Read The Invoices You Have SeenData TableService
  17. 17Match It Against A Purchase OrderCodeLogic
  18. 18Is It Clear To Pay?SwitchLogic
  19. 19Log It As ClearedData TableService

How it's built

Starts on
An arriving email
Steps
19, with 2 branches
Size
Medium: a working afternoon
Connects to
Gmail, n8n data table
Model
OpenAI

Questions

What does it need to run?

An n8n account, plus your own Gmail account, and a key for OpenAI. You connect your own accounts after importing it; none are included.

What starts it?

It starts on an arriving email.

Does it use AI?

Yes. It calls OpenAI. Model calls are billed by the provider, not by n8n.

How long does it take to set up?

Plan an afternoon. 19 steps is enough that you should read each one before running it.

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 19 steps before you point it at anything that matters.