# Route multi-step expense approvals with Gmail and HTTP API: n8n workflow

> Started by another system calling it, and works across Gmail. 17 steps, 4 branches: a working afternoon to understand properly.

Source: https://millionrounds.com/workflow/route-multi-step-expense-approvals-with-gmail-and-http-api (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)

# Route multi-step expense approvals with Gmail and HTTP API

Started by another system calling it, and works across Gmail. 17 steps, 4 branches: a working afternoon to understand properly.

Medium

[Download free](https://millionrounds.com/login?next=%2Fapp%2Fworkflow%2Froute-multi-step-expense-approvals-with-gmail-and-http-api)

**17 steps** Medium: a working afternoon

**4** Branches: places the flow splits

**0** Loops or waits

**1** Service it connects to

## The flow

Starts it 2 Logic 11 Service 4

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

- 1 **Request Received** Webhook *Starts it*
- 2 **Normalize & Validate** Code *Logic*
- 3 **Is Valid?** If *Logic*
- 4 **Route by Amount** Switch *Logic*
- 5 **Mark Invalid** Set *Logic*
- 6 **Auto-Approve** Set *Logic*
- 7 **Manager Approval** Gmail *Service*
- 8 **Director Approval** Gmail *Service*
- 9 **Build Decision Record** Code *Logic*
- 10 **Manager Approved?** If *Logic*
- 11 **Director Approved?** If *Logic*
- 12 **Log to System of Record** Http Request *Service*
- 13 **Manager Approved** Set *Logic*
- 14 **Mark Rejected** Set *Logic*
- 15 **Director Approved** Set *Logic*
- 16 **Notify Requester** Gmail *Service*
- 17 **Respond** Respond To Webhook *Starts it*

## How it's built

- **Starts on:** Another system calling it
- **Steps:** 17, with 4 branches
- **Size:** Medium: a working afternoon
- **Connects to:** Gmail
- **Model:** None. This is plumbing, not judgement

## Questions

What does it need to run?

An n8n account, plus your own Gmail 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. 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.

## 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%2Froute-multi-step-expense-approvals-with-gmail-and-http-api)
- **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.

## Connects to

Each opens the other workflows that use it.

[Gmail](https://millionrounds.com/workflows?service=Gmail#library)

## Workflows like it

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

- [**Fast-track expense reimbursements with UploadToURL** 17 steps · Gmail, Google Sheets](https://millionrounds.com/workflow/fast-track-expense-reimbursements-with-uploadtourl)
- [**Handle retail payment failures with Slack and Supabase** 17 steps · Gmail, Slack](https://millionrounds.com/workflow/handle-retail-payment-failures-with-slack-and-supabase)
- [**Send Mercado Pago billing links and reminders** 17 steps · Gmail, Google Sheets](https://millionrounds.com/workflow/send-mercado-pago-billing-links-and-reminders)
- [**Send invoice payment reminders with Gmail and Google Sheets** 17 steps · Gmail, Google Sheets](https://millionrounds.com/workflow/send-invoice-payment-reminders-with-gmail-and-google-sheets)
- [**Auto-extract & approve invoices with OpenAI and Jotform** 17 steps · calls a model · Gmail, Google Sheets](https://millionrounds.com/workflow/auto-extract-and-approve-invoices-with-openai-and-jotform)
- [**Automate tax compliance validation with OpenAI** 17 steps · calls a model · Gmail](https://millionrounds.com/workflow/automate-tax-compliance-validation-with-openai)