LeanInvoice
Support
Happy to help. Most questions are answered below; if yours isn't, just send us an email.
Is LeanInvoice available in English?
No. The app is German-language only and is released on the German App Store. It is built around German invoicing law, so an English version would be of little use outside Germany. These English pages exist for information only.
Who is LeanInvoice for?
For German small businesses filing under §19 UStG, anyone who issues invoices without charging VAT. LeanInvoice deliberately has no standard-taxation mode, no VAT rates, and no foreign currencies. If you need to show VAT on your invoices, LeanInvoice is not the right app for you.
How are invoice numbers assigned?
Sequentially, with a year prefix: 2026-001, 2026-002, and so on. The count restarts at 001 each year. The number is assigned when you save, not when you open the form. So abandoned drafts leave no gaps. If you already have an invoicing history, you can set the starting number in Settings.
Can I still edit an invoice I have already sent?
Not directly: sent and paid invoices are read-only. That is deliberate: an invoice sitting with your client should not change unnoticed. Genuine corrections go through a dedicated flow where you state a reason. The invoice number, recipient, and invoice date are preserved, and the change is recorded in the invoice. That entry is a memory aid for you, not tax evidence. How you present a correction to your client and the tax office is your decision.
Is LeanInvoice accounting software?
No. LeanInvoice captures invoices and turns them into a PDF. That is all. It is not bookkeeping software, not tax software, and no substitute for your tax adviser. The app carries no GoBD certification and is not certified for any commercial or tax purpose. Whether your entries are correct, whether you actually qualify under §19 UStG, and how you retain your invoices is entirely up to you.
Where is my data stored?
On your device and, if you leave iCloud sync enabled, in your private iCloud database. We run no servers and never see your invoices. You can verify this under Settings → Apple ID → iCloud → Apps Using iCloud.
Can I use LeanInvoice without iCloud?
Yes. Settings → iCloud Sync lets you turn synchronisation off; LeanInvoice then stores everything locally on the device. Note that your data is then only covered by your iPhone backup and will not reach your other devices.
The app is not syncing. What should I do?
Make sure you are signed in to iCloud and that LeanInvoice has iCloud access: Settings → Apple ID → iCloud → Apps Using iCloud. Inside LeanInvoice, Settings → iCloud Sync shows the current status along with the time of the last import and export, and tells you if an error occurred.
Does LeanInvoice support e-invoicing (XRechnung, ZUGFeRD)?
No. LeanInvoice produces PDF invoices. Small businesses filing under §19 UStG are exempt from the obligation to issue e-invoices and may continue to issue other invoice formats, including PDFs.