The Scenario
It's the last Thursday of the month. You have 25 client projects in the Project Billing tab — hours, rates, descriptions, contact IDs — all tracked across the month and now marked "ready to bill." In a normal world you'd spend Friday morning opening each project in Lexoffice, building the invoice, setting the VAT rate, and sending it off. That's four or five hours of form-filling for work you've already done.
The bad version:
- Open Lexoffice, navigate to Invoices, click New Invoice, find the contact by name, add the line item, enter the description, set the net amount, pick the VAT rate — and repeat for all 25 projects
- Make a typo on invoice 11, realize it after you've finalized it, and spend 20 minutes figuring out whether to void it or issue a credit note
- Finish at 6 PM on a Friday, exhausted, with three invoices still in draft because the contact ID in the sheet didn't match anything in Lexoffice and you weren't sure what to do
Your value is in the project work and the client relationship. Invoice generation is not where your time belongs.
The Easy Way: One Prompt in SheetXAI
SheetXAI is an AI agent that lives inside your Google Sheet. It reads the project data and talks to Lexoffice on your behalf — building each draft invoice from the row without you touching the form.
Open the Project Billing tab and type:
Create a draft Lexoffice invoice for each row using contact ID in column A, description in B, net amount in C, and VAT rate in D
What You Get
- A draft Lexoffice invoice created for each row, with line item, net amount, and VAT rate mapped correctly
- The Lexoffice invoice ID written back into the sheet for every row that succeeded — plus an error note for rows where the contact ID wasn't found so you can investigate before sending
- All 25 invoices built in the time it takes to write one sentence
What If the Data Is Not Quite Ready
Only some rows are ready to bill
Create a draft Lexoffice invoice for each row in the Project Billing tab where column E says "ready to bill" — use contact ID in A, description in B, net amount in C, and VAT rate in D
The VAT rate column contains mixed formats — some rows have decimals, some have percentages
For all rows in this sheet where column E is "ready to bill", normalize the VAT rate in column D (convert any percentage values to decimal), then create a draft Lexoffice invoice using contact ID in A, description in B, net amount in C, and the corrected VAT rate
Some rows have multiple line items split across sub-rows and need to be grouped into one invoice
Group the rows in this sheet by the project code in column F, sum the net amounts in column C for each group, then create one draft Lexoffice invoice per group using the contact ID from the first row, the project name as the description, the total net amount, and the VAT rate in column D
You want to build, validate, and finalize all in one pass
For all rows in the Project Billing tab where column E is "ready to bill": check that the contact ID in column A resolves to a valid Lexoffice contact, create a finalized Lexoffice invoice for each valid row using description in B, net amount in C, and VAT rate in D, write the invoice ID into column G, and flag any rows where the contact lookup failed with "contact not found" in column H
Cleanup, validation, and invoice creation in one prompt.
Try It
Get the 7-day free trial of SheetXAI and open your project billing sheet — then ask it to generate the Lexoffice invoices in one pass. You can also look at how to export open invoice payment status, or return to the full Lexoffice integration overview.