Lexoffice Automation: Connect Your Accounting with n8n and Make.com

Lexoffice is Germany's most popular cloud accounting software for freelancers and small businesses. With over 300,000 users, Lexoffice has established itself as a modern alternative to traditional accounting solutions. The major advantage: Lexoffice offers a modern REST API that makes automation significantly easier.

Why Automate Lexoffice?

Typical manual tasks:

Potential time savings: 15-20 hours/month for typical SMBs. For the budget side, see our comprehensive guide to what a build like this costs to implement and run.

Lexoffice API: The Basics

Setting Up API Access

Lexoffice -> Settings -> Public API

Generate API key

Store key securely (only visible once!)

Available API Endpoints

API Limits

• 100 requests/minute - Standard limit
• Pagination - Max 100 entries per request
• Rate limiting - 429 error when exceeded

Tip: Build batching and caching into your workflows.

The 10 Most Important Lexoffice Automations

1. Shopify/WooCommerce -> Lexoffice Invoices

Trigger: New order in shop

Workflow:

Shop (New Order)
        |
    Check/create customer data
        |
    Create invoice in Lexoffice
        |
    Send PDF to customer
        |
    Mark order as "invoiced"

n8n Implementation:

// Create Lexoffice invoice
{
  "voucherDate": "2024-01-15",
  "address": {
    "name": order.customer.name,
    "street": order.shipping.address,
    "zip": order.shipping.zip,
    "city": order.shipping.city,
    "countryCode": "DE"
  },
  "lineItems": order.items.map(item => ({
    "type": "custom",
    "name": item.name,
    "quantity": item.quantity,
    "unitPrice": {
      "netAmount": item.price,
      "taxRatePercentage": 19
    }
  })),
  "totalPrice": {
    "currency": "EUR"
  }
}

2. Automatic Receipt Capture

Trigger: Email with attachment or upload to folder

Workflow:

Email/Dropbox (new receipt)
        |
    OCR extraction
        |
    Lexoffice: Create voucher
        |
    Automatic categorization
        |
    If unclear: Slack notification

Make.com Scenario:

Watch: Gmail -> new emails with attachments

Filter: Only PDFs and images

OCR: Mindee or Google Vision

Create: Lexoffice -> Create Voucher

Notify: Slack on success/error

3. CRM Synchronization

Trigger: New contact in HubSpot/Pipedrive

Workflow:

CRM (New Customer)
        |
    Check: Exists in Lexoffice?
        |
    No: Create contact
    Yes: Update contact
        |
    Save Lexoffice ID in CRM

4. Automatic Payment Reminders

Trigger: Daily at 9:00 AM

Workflow:

Schedule (daily)
        |
    Lexoffice: Get open invoices
        |
    Filter: Overdue > 7 days
        |
    For each invoice:
      - Level 1: Payment reminder
      - Level 2: 1st reminder notice
      - Level 3: 2nd reminder notice
        |
    Send email
        |
    Update status in Lexoffice

5. Quote to Invoice Conversion

Trigger: Quote accepted

Workflow:

Quote Status: Accepted
        |
    Lexoffice: Retrieve quote
        |
    Create invoice from quote
        |
    Generate PDF
        |
    Send to customer

6. Recurring Invoices

Trigger: Monthly on the 1st

Workflow:

Schedule (1st of month)
        |
    List: Get subscription customers
        |
    For each customer:
      - Create invoice
      - Send PDF
      - Trigger SEPA direct debit

7. Bank Integration with AI

Trigger: New bank transactions (via finAPI)

Workflow:

finAPI (new transactions)
        |
    AI: Categorization
    (GPT-4/Claude)
        |
    Lexoffice: Match payment
        |
    Unclear bookings: For review

8. Accountant Report

Trigger: End of month

Workflow:

Schedule (last day of month)
        |
    Lexoffice: Get monthly summary
        |
    Create Excel/PDF report
        |
    Email to accountant

9. Expense Approval

Trigger: New receipt above threshold

Workflow:

Lexoffice (new receipt > 500 EUR)
        |
    Slack: Request approval
        |
    Wait for response
        |
    Approved: Release receipt
    Rejected: Mark receipt

10. Inventory Sync

Trigger: Stock level changes

Workflow:

Inventory System (stock change)
        |
    Lexoffice: Update item
        |
    If below threshold: Reorder suggestion

Step-by-Step: Shop to Lexoffice with n8n

Prerequisites

• n8n Cloud or Self-Hosted
• Lexoffice API key
• Shopify/WooCommerce admin access

Building the Workflow

Step 1: Set up trigger

Node: Shopify Trigger
- Event: Order Created
- Credentials: Shopify OAuth

Step 2: Check/create contact

Node: HTTP Request
- Method: GET
- URL: https://api.lexoffice.io/v1/contacts
- Query: email={{ $json.customer.email }}
- Headers: Authorization: Bearer YOUR_API_KEY

Node: IF
- Condition: Contact exists?
- Yes: Use contact ID
- No: Create contact

Step 3: Create invoice

Node: HTTP Request
- Method: POST
- URL: https://api.lexoffice.io/v1/invoices
- Body: (see JavaScript below)

{
  "voucherDate": "{{ $now.format('yyyy-MM-dd') }}",
  "address": {
    "contactId": "{{ $('Contact').item.json.id }}"
  },
  "lineItems": [
    {{#each $json.line_items}}
    {
      "type": "custom",
      "name": "{{ this.name }}",
      "quantity": {{ this.quantity }},
      "unitPrice": {
        "netAmount": {{ this.price }},
        "taxRatePercentage": 19
      }
    }{{#unless @last}},{{/unless}}
    {{/each}}
  ],
  "taxConditions": {
    "taxType": "net"
  },
  "shippingConditions": {
    "shippingType": "delivery",
    "shippingDate": "{{ $now.plus(3, 'days').format('yyyy-MM-dd') }}"
  },
  "paymentConditions": {
    "paymentTermLabel": "Payable within 14 days",
    "paymentTermDuration": 14
  }
}

Step 4: Finalize invoice

Node: HTTP Request
- Method: POST
- URL: https://api.lexoffice.io/v1/invoices/{{ $json.id }}/document

Step 5: Send PDF

Node: HTTP Request
- Method: GET
- URL: https://api.lexoffice.io/v1/invoices/{{ $json.id }}/document
- Response: Binary

Node: Send Email
- To: {{ $('Shopify Trigger').item.json.customer.email }}
- Subject: Your Invoice {{ $json.voucherNumber }}
- Attachment: Invoice PDF

Make.com: Using Lexoffice Modules

Make.com offers native Lexoffice modules:

Available Modules

Example Scenario

Shopify -> Watch Orders

Lexoffice -> Search Contact (by Email)

Router:

- Contact exists -> continue

- Contact missing -> Create Contact

Lexoffice -> Create Invoice

Lexoffice -> Finalize Invoice

Gmail -> Send Email with Attachment

Error Handling

Common Errors

Best Practice: Retry Logic

// n8n Code Node
const maxRetries = 3;
let attempt = 0;

while (attempt < maxRetries) {
  try {
    // API Request
    return result;
  } catch (error) {
    if (error.response?.status === 429) {
      await new Promise(r => setTimeout(r, 60000)); // Wait 1 min
      attempt++;
    } else {
      throw error;
    }
  }
}

Security and Compliance

Protect API Key

• Never hardcode in code
• Use n8n Credentials
• Rotate regularly

GoBD Compliance

• Lexoffice is GoBD-certified
• Automation doesn't change that
• Observe archiving requirements

GDPR

• Process customer data only for intended purposes
• Observe deletion deadlines (Lexoffice supports this)

Cost-Benefit Analysis

Investment

Savings

At 40 EUR/hour = 780 EUR/month savings

Advanced Integrations

Lexoffice + Stripe

For a step-by-step guide on payment webhooks, see our Stripe webhook setup tutorial. Automatically create invoices for Stripe payments:

Stripe Webhook (Payment Success)
        |
    Lexoffice: Create invoice
        |
    Lexoffice: Mark as paid

Lexoffice + Calendly

For service providers with booking systems:

Calendly (Appointment booked)
        |
    Lexoffice: Create contact
        |
    Lexoffice: Create invoice
        |
    Send email with invoice

Lexoffice + Notion

Project-based billing:

Notion (Project completed)
        |
    Extract time entries from Notion
        |
    Lexoffice: Invoice with line items

Conclusion

Lexoffice is an ideal candidate for automation thanks to its modern API. With n8n or Make.com you can:

• Automatically create invoices from shop systems
• Intelligently capture and categorize receipts
• Fully automate payment reminders
• Generate accountant reports at the click of a button

Time spent on accounting drops by 80-90%.

Next Steps

Create API key - Activate in Lexoffice

Build first workflow - e.g., Shop -> Invoice

Expand gradually - Connect additional processes

If you run a Shopify store, the Shopify to Lexoffice integration is the shortest route from order to booked invoice. We support you with Lexoffice automation - from analysis to finished integration. If you are a tax firm, also read our guide on automation for tax consultants. Contact us for a free consultation.