Automation library · Money admin

Check supplier invoices from Gmail with OpenAI

Started by an arriving email, and works across Gmail, Google Sheets and Slack. It hands the judgement calls to OpenAI. 17 steps, 2 branches: a working afternoon to understand properly.

MediumCalls a model: OpenAI

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17 stepsMedium: a working afternoon
2Branches: places the flow splits
0Loops or waits
3Services it connects to

The flow

Starts it 2Model 2Logic 4Service 9

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

  1. 1Invoice arrives by emailGmail triggerStarts it
  2. 2Extraction modelLm Chat Open AiModel
  3. 3If the run breaksError triggerStarts it
  4. 4Keep only PDF attachmentsFilterLogic
  5. 5Pull the invoice fieldsInformation ExtractorModel
  6. 6Alert finance that it brokeSlackService
  7. 7Read the PDFExtract From FileService
  8. 8Supplier masterGoogle SheetsService
  9. 9Open purchase ordersGoogle SheetsService
  10. 10Invoices already postedGoogle SheetsService
  11. 11Run the checksCodeLogic
  12. 12Did every check pass?IfLogic
  13. 13Inside the approval limit?IfLogic
  14. 14Park it in the exceptions queueGoogle SheetsService
  15. 15Post it to the ledgerGoogle SheetsService
  16. 16Ask a human to sign it offSlackService
  17. 17Tell the supplier what is wrongGmailService

How it's built

Starts on
An arriving email
Steps
17, with 2 branches
Size
Medium: a working afternoon
Connects to
Gmail, Google Sheets, Slack
Model
OpenAI

Questions

What does it need to run?

An n8n account, plus your own Gmail, Google Sheets and Slack accounts, 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. 17 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 17 steps before you point it at anything that matters.