# Process supplier invoices with Slack: n8n workflow template

> Started by another system calling it. It calls services over plain HTTP rather than through connectors.

Source: https://millionrounds.com/workflow/process-supplier-invoices-with-slack (Millionrounds; every figure on the page links to its filing or article)

[Automation library](https://millionrounds.com/workflows) · [Money admin](https://millionrounds.com/workflows?category=Money+admin#library)

# Process supplier invoices with Slack

Started by another system calling it. It calls services over plain HTTP rather than through connectors. 16 steps, 1 branch: a working afternoon to understand properly.

Medium

[Download free](https://millionrounds.com/login?next=%2Fapp%2Fworkflow%2Fprocess-supplier-invoices-with-slack)

**16 steps** Medium: a working afternoon

**1** Branch: places the flow splits

**0** Loops or waits

**0** Services by connector: it calls them over plain HTTP

## The flow

Starts it 3 Logic 6 Service 7

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

- 1 **Webhook: invoice received (email, drive or upload)** Webhook *Starts it*
- 2 **Error trigger** Error trigger *Starts it*
- 3 **Config** Set *Logic*
- 4 **Config (errors)** Set *Logic*
- 5 **AI: extract fields from document** Http Request *Service*
- 6 **Alert ops (Slack)** Http Request *Service*
- 7 **Accounting: supplier master** Http Request *Service*
- 8 **Accounting: open purchase orders** Http Request *Service*
- 9 **Merge lookups** Merge *Logic*
- 10 **Validate: TRN, duplicate, totals, PO match, limit** Code *Logic*
- 11 **Route by status** Switch *Logic*
- 12 **Accounting: post bill** Http Request *Service*
- 13 **Review queue: human check** Http Request *Service*
- 14 **Slack: rejected, AP notified** Http Request *Service*
- 15 **Outcome** Code *Logic*
- 16 **Respond 200 (invoice handled)** Respond To Webhook *Starts it*

## How it's built

- **Starts on:** Another system calling it
- **Steps:** 16, with 1 branch
- **Size:** Medium: a working afternoon
- **Connects to:** Nothing by connector; it calls services over plain HTTP
- **Model:** None. This is plumbing, not judgement

## Questions

What does it need to run?

An n8n account. 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?

Plan an afternoon. 16 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 16 steps before you point it at anything that matters.

## Run it in n8n

- **Create your n8n account** Free to start. n8n is where the workflow runs. [Create an n8n account ↗](https://millionrounds.com/n8n)
- **Download the workflow** Free with a Millionrounds account. [Download free](https://millionrounds.com/login?next=%2Fapp%2Fworkflow%2Fprocess-supplier-invoices-with-slack)
- **Paste it into n8n** Open a new workflow in n8n and paste. Then connect your own accounts.

Stored with the author's traces removed: canvas notes, instance identifiers, saved credential names and any live document they had left behind.

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Also money admin, with the same services where possible, closest in size first.

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- [**Jotform commerce sync: Telegram confirmation & Zoho invoice** 16 steps · Google Sheets, Telegram](https://millionrounds.com/workflow/jotform-commerce-sync-telegram-confirmation-and-zoho-invoice)