First check: Office or Desktop?
Lexware runs two product lines that are easily confused. Lexware Office is the cloud product you use in a browser with an online login. Before the rename it was called lexoffice. Alongside it are the classic desktop programs such as Lexware buchhalter or financial office, installed as software on your machine.
zrapp works exclusively with Lexware Office. The desktop line offers no comparable interface. If you are unsure which one you run, settle that before installing. It saves you a setup that cannot work.
This connection requires Lexware Office XL. Lower plans may support invoicing but do not provide the Public API access used by zrapp. For existing accounts, check the features actually enabled.
Connect step by step
Install zrapp from the Shopify App Store. In Lexware Office, open “Extensions → More apps → Public API” or the API key manager. Create a dedicated key for the integration and copy it before closing the window.
Enter the key in zrapp’s Lexware Office settings. Check the connection and permissions for the features you use. Lexware supports restricted permissions; a restricted key must allow every resource your configured workflow actually requires.
Configure tax mode, invoice creation, delivery and optional delivery notes. First transfer a paid test order and check the customer, line items, VAT and invoice number. Automatic transfer requires a connected integration, an active trial or subscription, and enabled automation. Also monitor your API key’s expiry date.
What gets transferred
zrapp maps the Shopify order onto a document in Lexware Office: contact details, line items with quantity and unit price, shipping, discounts and the assigned tax rates. The document reference carries the Shopify order number.
Existing contacts in Lexware Office are left alone. A matching contact is used, not overwritten, so maintained master data survives.
When a document is created
Three conditions have to come together: the Lexware Office integration is connected, billing is active, and automation is switched on.
Receiving the order does not trigger an invoice. Payment does. That prevents documents for orders that are never paid and would then have to be cancelled.
How the tax treatment is decided
zrapp assigns every order to a tax case technically, based on your configuration, the delivery country and the data present on the order. The assignment follows fixed priorities so the result stays traceable in every constellation.
This is a technical classification, not a tax review. Special cases (missing export evidence, contradictory customer data) remain items to review. This article is not tax or legal advice; it reflects September 2026.
- Priority 0 (small-business configuration): the app creates documents without VAT and with a §19 note. First check eligibility, especially for foreign sales; technical priority does not confirm legal treatment.
- Priority 1 (EU B2B configuration): order data is technically mapped to a tax case. Goods supplies and reverse-charge services each require the appropriate conditions and evidence. A VAT ID alone does not replace those checks.
- Priority 1.5 (tax exempt): if all line items are marked as non-taxable in Shopify, the document is issued without tax accordingly.
- Priority 2 (standard rules): domestic at the German rate, EU consumers depending on your OSS configuration, non-EU without VAT.
E-invoicing: profiles, routing ID and buyer reference
zrapp supports the e-invoicing profiles offered by Lexware Office, including XRechnung and ZUGFeRD. For an XRechnung, public-sector buyers require additional recipient details, typically a routing ID, the buyer reference.
You maintain that on the contact in Lexware Office, not in zrapp. Without it the document can be formally incomplete and rejected by the recipient.
For context: since 1 January 2025 domestic companies in Germany must be able to receive e-invoices in B2B; the obligation to issue them is being phased in. Whether a given document has to be an e-invoice depends on the transaction and is a question for your tax adviser.
Delivery note on fulfilment
One difference from the sevdesk integration: depending on your configuration, zrapp creates a delivery note in Lexware Office on fulfilment, that is, when the order is marked as shipped in Shopify.
That is useful if you want the shipping step documented without operating a second tool for it. If you do not need a delivery note, leave the option off.
Historical import
If you set zrapp up mid-financial-year, your earlier orders are not in Lexware Office. The historical import transfers orders retroactively from a date you choose.
Before you start, check whether documents already exist for that period. Otherwise you create duplicates you then have to sort out by hand.
What flows back to Shopify
After each document, zrapp writes the data back onto the Shopify order as metafields in the `zrapp` namespace: document ID, number, status and timestamp. That shows you on the order which invoice number Lexware Office assigned.
zrapp additionally tags documents by tax treatment: domestic, reverse charge, OSS, non-EU, small business or country-XX. That simplifies the VAT return and the handover to your tax adviser.
Credit notes and refunds
On a refund, zrapp automatically creates a full credit note against the original invoice, regardless of whether the refund in Shopify was full or partial.
Partial refunds therefore have to be corrected in Lexware Office by hand. Alternatively, switch the automatic credit note off in the settings.
sevdesk or Lexware Office?
Which of the two suits you better is a separate question from this guide and is covered in sevdesk or Lexware Office for Shopify. In practice it usually comes down to what your tax adviser already works with. That weighs more than any feature comparison.
zrapp supports both. The sevdesk setup is described in connecting Shopify to sevdesk.
Honest limits
This is what zrapp deliberately does not do:
- No Lexware Desktop: the cloud product Lexware Office only.
- No qualified VIES check: the reverse-charge assignment uses the VAT ID on the order but does not verify it.
- No partial credit note: refunds always produce a credit note for the full amount.
- No routing ID management: that detail belongs on the contact in Lexware Office.
