# Billing and Invoicing

Invoicing is handled by your preferred invoicing solution, and the generated invoices are recorded as receivables in Bkper through automations. This way, your receivable balances always reflect the actual amount to collect.

There are many online invoicing solutions available — such as [ZipBooks](https://zipbooks.com/), [Invoice Ninja](https://www.invoiceninja.com/), [Zoho](https://www.zoho.com/invoice/), and [Yamm](https://yet-another-mail-merge.com/) — that connect to Bkper without programming through automations like the [Google Sheets Add-on for Bkper](https://bkper.com/blog/turn-google-sheets-into-a-powerful-accounting-tool/).

The [Bkper API](https://bkper.com/api) also lets you customize and extend Bkper into Google Workspace, so you can build your own solutions and automate workflows — including invoicing — with simple Google Apps Scripts that fully integrate with Google Workspace.