XRechnung and ZUGFeRD E-Invoicing for WHMCS
Issue German e-invoices from WHMCS: XRechnung XML and ZUGFeRD hybrid PDFs for business clients, checked against the official rules before they go out.
What will the e-invoicing addon do?
When WHMCS creates an invoice for a German business client, the addon builds a structured e-invoice from it. You choose the format per client: an XRechnung XML file (CII or UBL syntax), or a ZUGFeRD hybrid PDF that a person can read and accounting software can import. Each file is checked against the official validation rules before it is sent. One that fails waits in a queue with the reason, so a broken invoice never reaches the client. Consumers and clients outside Germany keep receiving your normal PDF.
This product is built to order: you get the license key at purchase and the download within 20 business days.
Why does a WHMCS seller in Germany need it?
Since 1 January 2025, an invoice between two German businesses has to be an e-invoice, and the business receiving it cannot refuse one (§ 14 UStG). A transition rule in § 27 (38) UStG lets sellers keep sending paper invoices, or a PDF if the client agrees, for supplies until 31 December 2026. If your total turnover in the previous year was €800,000 or less, the rule runs until 31 December 2027. Invoices of up to €250 are exempt (§ 33 UStDV). A plain PDF is not an e-invoice, even when it is sent by email.
What does WHMCS already do, and what does this add?
WHMCS sells its own E-Invoicing module by monthly subscription for WHMCS 9.0 and newer, but it covers clients in Belgium only and sends through the Peppol network. For Germany, WHMCS produces PDF invoices only. This addon adds the German formats, validation, a Leitweg-ID for public-sector buyers and an archive of the original files. If you also use my German Invoice PDFs addon, the ZUGFeRD file uses that PDF as its visible part.
What is included?
| Part | What you get |
|---|---|
| XRechnung | XML in CII or UBL syntax, chosen per client |
| ZUGFeRD | A hybrid PDF with the EN 16931 or XRechnung profile, attached to the invoice email |
| Credit notes | WHMCS 9 credit notes sent as e-credit notes that refer to the original invoice |
| Client rules | German business clients found from country and VAT number, with a switch for the €250 limit and your transition date |
| Public-sector buyers | Leitweg-ID and purchase order number fields per client |
| Validation | Checks against the official KoSIT rules, with a queue for files that fail |
| Archive | The original file stored with a checksum, downloadable by the client in the client area |
| Austria | A UBL file you can upload to the federal e-invoice portal for Austrian public-sector clients |
Who is it for?
Hosting companies, agencies and software sellers in Germany that bill German business clients through WHMCS. If you have no business clients in Germany, you do not need it.
What do you need, and what are the limits?
Requirements: WHMCS 8.13 or 9.x (I confirm your exact version at purchase), PHP 8.1 or newer, your VAT number and full company details in the WHMCS settings, and a VAT number on each business client.
Limits: the addon creates and sends e-invoices; it does not receive or check invoices from your own suppliers, and it does not send through the Peppol network, which Germany does not require. Each new XRechnung version needs an update, included for the first twelve months. It is not tax advice, so agree the setup with your tax advisor.
It costs $199 once for a lifetime license with twelve months of updates and support, the license key at purchase and the download within 20 business days, and a seven-day refund window.
Key features
- XRechnung XML in CII or UBL syntax
- ZUGFeRD hybrid PDF with the EN 16931 or XRechnung profile
- WHMCS 9 credit notes sent as e-credit notes
- Format chosen per client, normal PDF kept for consumers
- German business clients found from country and VAT number
- Switch for the €250 limit and your transition date
- Leitweg-ID and purchase order number per client
- Validation against the official KoSIT rules before sending
- Queue for files that fail, with the reason
- Original file archived with a checksum and downloadable in the client area
Why customers buy this module
- →German business clients receive invoices in the format the law requires
- →No broken e-invoice reaches a client unchecked
- →Public-sector clients get the Leitweg-ID they ask for
- →Consumers keep the PDF they already know
Frequently asked questions
Do I need e-invoices if my turnover is small?
Every German business has had to be able to receive e-invoices since 1 January 2025. For sending, the transition rule in § 27 (38) UStG lets businesses with previous-year turnover of €800,000 or less keep sending paper invoices, or PDFs their clients agree to, until 31 December 2027; above that, until 31 December 2026. Confirm your own date with your tax advisor.
XRechnung or ZUGFeRD: which should I send?
Both count as e-invoices. Public-sector buyers usually ask for XRechnung with a Leitweg-ID. Many businesses prefer ZUGFeRD because it opens as a normal PDF and still carries the data for their software. The addon lets you set the format per client, so you can follow what each client asks for.
When will I get it, and what if you can't deliver?
You get the license key at purchase and the download within 20 business days of purchase. If I do not deliver it in that time, you get a full refund. Otherwise the store's seven-day refund window applies.
Technical specifications
- WHMCS
- 8.13 and 9.x (confirmed at purchase)
- PHP
- 8.1+
- Formats
- XRechnung (CII, UBL), ZUGFeRD EN 16931 and XRechnung profiles
- Validation
- KoSIT rules
- Availability
- Built to order, delivered in 20 business days
- License
- Lifetime, 1 year of updates and support included
- Delivery
- Instant download and license key
- Refund window
- 7 days
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