Last week, I automated the invoice intake for our company. Not as a concept. Not as a PowerPoint. As a working workflow that’s been running since Tuesday and saves me three hours a week. This article isn’t a guide — it’s a blueprint. By the end, you’ll have a functioning automated process.
What follows are 10 concrete steps to automate your first business process. I’m using invoice intake as the example — because every company has one, everyone knows the pain, and the solution takes 4–6 hours to build.
When someone asks me where to start automating business processes, I always say: pick the process that annoys you the most and is also the most predictable. Invoice intake checks both boxes.
Think for a moment about what happens today when an invoice arrives: an email lands in the inbox. Someone opens it. Opens the attachment. Reads the invoice number, the amount, the due date. Types it into a spreadsheet or accounting tool. Saves the PDF in a folder. That’s 5–8 minutes per invoice. With 40 incoming invoices per month, that’s a good three hours of mindless data entry.
The process is perfect for automation because it has three qualities: it’s repetitive, it’s rule-based, and an error isn’t catastrophic.
At Exasync, we set up exactly this workflow for our own invoices. The architecture: incoming email is detected, n8n triggers the workflow, the PDF is analyzed, the data lands in our Supabase database, and a notification goes to Slack.
Before you build a single workflow, you need three things. Not ten. Three things, all free.
First: n8n. This is the heart of the automation. n8n is an open-source workflow automation tool — comparable to Zapier or Make, but with one crucial difference: you can run it on your own server. For getting started, the free n8n Cloud with 5 active workflows is sufficient. n8n vs Zapier vs Make comparison
Second: Supabase. This is our database. Supabase is an open-source alternative to Firebase and offers a PostgreSQL database with real-time features. The free tier is perfectly adequate for most SMEs.
Third: An email inbox with IMAP access. You already have this. Gmail, Outlook, Strato — everything works.
Time required for this step: 30 minutes.
The workflow consists of 5 nodes in n8n:
Node 1: IMAP Email Trigger — Monitors your inbox and fires when a new email with a PDF attachment arrives.
Node 2: HTTP Request — Sends the PDF to an OCR/parsing service.
Node 3: Function (JavaScript) — Extracts invoice number, amount, IBAN, and date via regex.
Node 4: Supabase Insert — Writes the structured data to your database.
Node 5: Slack/Teams Notification — Sends a summary.
The entire chain runs automatically. Once an invoice arrives by email, it takes 15–30 seconds for the data to appear in the database.
Total time for initial setup: approximately 4–6 hours.
Step 1: Install n8n or create a cloud account (20 minutes)
Option A: n8n Cloud at app.n8n.cloud. Option B (our recommendation): self-hosted on a Hetzner server. CX22 for 4.50 euros per month is enough. Ubuntu 24.04, install Docker, then:
docker run -d --name n8n -p 5678:5678 -v n8n_data:/home/node/.n8n n8nio/n8n
Step 2: Create email credentials in n8n (10 minutes)
Settings, Credentials, New Credential, IMAP. Host, Port 993, User, Password. Tip: test the connection directly in n8n.
Step 3: Create the IMAP Email Trigger node (15 minutes)
New workflow. Add Email Trigger (IMAP). Mailbox = INBOX, Format = Resolved. Download Attachments set to true. Poll interval set to 5 minutes.
Step 4: Extract PDF text with HTTP Request node (30 minutes)
Use n8n’s built-in Extract from File node for direct PDF text extraction. For scanned PDFs, you’ll need OCR.space: HTTP Request node, Method POST, URL https://api.ocr.space/parse/image.
Step 5: Parse invoice data with JavaScript function (60–90 minutes)
The most involved step. Add a Code node (JavaScript). Invoice number: /Rechnung(?:s?-?\s?(?:Nr|Nummer|No)\.?)?\s*:?\s*([A-Z0-9\-\/]+)/i. Amount: /(?:Brutto|Gesamt|Total|Endbetrag)\s*:?\s*([\d.,]+)\s*(?:EUR|\u20AC)/i. IBAN: /[A-Z]{2}\d{2}\s?\d{4}\s?\d{4}\s?\d{4}\s?\d{4}\s?\d{0,2}/.
Tip: collect 5–10 real invoices and test your regex patterns against them. 80% automation with 20% manual follow-up is better than 0%.
Step 6: Set up Supabase database and table (30 minutes)
New project on supabase.com (Frankfurt region for GDPR). SQL Editor: CREATE TABLE invoices with fields for id, invoice_number, supplier, amount, iban, due_date, status, email_subject, pdf_link, created_at. Enable RLS.
Step 7: Configure Supabase Insert node in n8n (15 minutes)
Create credential with Project URL and Service Role Key. Supabase node: Operation = Insert, Table = invoices. Map fields. Tip: convert amount with parseFloat(amount.replace(’,’, ’.’)).
Step 8: Set up notifications (15 minutes)
Slack node or Teams webhook. Message: New invoice received: [Supplier] — [Amount] EUR — due [Date] — Invoice No. [Number].
Step 9: Error handling and edge cases (30 minutes)
Problem 1: Email without PDF attachment — IF node that checks for binary attachment. Problem 2: OCR can’t read the text — set status to manual_review. Problem 3: Duplicate invoices — duplicate check via Supabase GET before insert.
Step 10: Activate workflow and monitor (10 minutes)
Toggle to Active. Send a test invoice. Set up an error workflow for automatic error notifications.
Mistake 1: Too much at once. One workflow per sprint. Finish it, test it, let it run.
Mistake 2: Aiming for perfect extraction. 80% is enough. Status manual_review for the rest.
Mistake 3: No test data. Run 5–10 PDFs through it beforehand.
Mistake 4: Hardcoding credentials. Always use n8n’s credential management.
Mistake 5: No monitoring. An error workflow is mandatory.
Once invoice intake is running, you have a working automation setup. The next workflow is ten times faster to build.
1. Build an invoice dashboard (2 hours). Display Supabase data as a dashboard.
2. Partially automate payment reminders (3 hours). Second n8n workflow for overdue invoices.
3. Identify more processes. Order confirmations, time-off requests, proposal creation. Optimize Business Processes
At Exasync, we go even further: our CFO agent Plutus monitors the invoice table in real time and generates monthly cash flow forecasts. Automate Accounting
The honest math that most guides leave out: automation costs time upfront. The question is when that investment pays for itself.
One-time costs for the invoice workflow:
Ongoing savings per month:
Break-even: After 6–8 weeks, the setup has paid for itself. From then on, you save every month. At Exasync, break-even came even sooner because we built three additional workflows on the same infrastructure in parallel — the second workflow doesn’t need new server setup.
An important insight from our practice: ROI doesn’t grow linearly — it grows exponentially. Workflow 1 costs 5 hours. Workflow 2 costs 2 hours. Workflow 5 costs 45 minutes — because the building blocks are reusable.
For comparison: an external consultant charges between 2,000 and 8,000 EUR for the same automation. Building it yourself with n8n costs only your own time — and afterward, you understand what’s running. That’s critical because you can adjust the workflow yourself later when invoice formats change or new suppliers come on board.
One more tip on cost optimization: start with the free n8n Cloud. Only when you have more than 5 active workflows does switching to your own server make sense. At Exasync, over 30 workflows now run on a single Hetzner server for 4.50 EUR per month. The total cost for our entire process automation is under 20 EUR monthly — that’s less than lunch. Calculate Automation ROI
After invoice intake, the question is: what comes second? Not every process is equally well suited. Here’s the prioritization matrix we use at Exasync:
Automate immediately (high time expenditure + simple rules):
Automate with caution (complex + error-prone):
Hands off (too rare or too critical):
For every new candidate, we ask three questions: How often does it happen per week? How rule-based is the process? What’s the worst case if there’s an error? If the answers are “often,” “very rule-based,” and “not a big deal,” we automate immediately. These three questions have saved us from several bad calls at Exasync — once we wanted to fully automate contract creation until we realized the process only happens twice a month and looks different every time. The time saved would never have justified the effort. 5 Processes Every SME Should Automate
If you’d rather not set up the invoice workflow on your own — Contact. No sales pitch, just an honest assessment of whether automation makes sense at your volume.
