Creating e-invoices in the browser is absolutely possible but has one little caveat. If you want to embed a PDF version of the invoice to be embedded into an XML invoice format or if you are targetting a hybrid Factur-X/ZUGFeRD format, you have to always provide a PDF. The server and commandline versions can also create a PDF from a spreadsheet file but that is not possible in the browser because it requires executing LibreOffice.
The form below will create an e-invoice. You can see the source code in the source of this page at https://raw.githubusercontent.com/gflohr/e-invoice-eu/refs/heads/main/packages/docs/en/docs/other/browser-example.md!
The application uses a wizard-like approach. No data is sent to a server. The processing of the input data and generation of the invoice happens entirely in your browser.
The application is not meant to be a serious invoice generation portal but just a show case for the capabilities of the E-Invoice-EU library for the browser. Please make sure that you have filled all required input fields marked with `(*)` before you generate the invoice because the error handling of the application is only rudimentary.