Send invoice approval requests to Slack using easybits Extractor

Description

What This Workflow Does
Upload an invoice (PDF, PNG, or JPEG) via a hosted web form. The file is sent to easybits Extractor, which extracts key invoice data (supplier, amount, date, etc.). Based on the amount, an approval tier is assigned. The invoice details are then posted to Slack with interactive Approve / Reject / Flag buttons.

How It Works
Form Upload – A user uploads an invoice through the n8n web form
Extraction via easybits – The data URI is POSTed to the easybits Extractor, which returns structured invoice data
Field Mapping – Extracted fields are mapped + approval tier is calculated based on amount
Slack Notification – A message is posted to Slack with invoice details and interactive buttons

Approval Tiers
🟢 Standard: < €1,000
🟡 Medium: €1,000 – €5,000
🔴 High: > €5,000

Setup Guide

1. Create Your easybits Extractor Pipeline
Go to extractor.easybits.tech and create a new pipeline
Add the following fields to the mapping:
vendor_name – The supplier/company name on the invoice
invoice_number – The invoice reference number
invoice_date – The date on the invoice
total_amount – The total amount due (number only)
customer_name – The recipient/customer name
Copy your Pipeline ID and API Key

2. Connect the Nodes in n8n
Add the easybits Extractor node from the n8n community nodes
Enter your Pipeline ID and API Key as credentials
Create a Slack API credential using your Slack Bot Token and assign it to the Slack node
Update the Slack channel ID in the Send to Slack for Approval node to your target channel

3. Set Up the Slack App
Go to api.slack.com/apps and create a new app
Add Bot Token Scopes: chat:write, chat:write.public
Install the app to your workspace
Copy the Bot User OAuth Token (starts with xoxb-)
Enable Interactivity and set the Request URL to your approval handler webhook

4. Activate & Test
Click Active in the top-right corner of n8n
Open the form URL and upload a test invoice
Check Slack – you should see the approval message with buttons