Choosing between an API connection and file upload is a business process decision as much as a technical one. Consider how frequently invoices are issued, how often data needs to move, and how much manual work your team can manage.
An API integration connects systems through a defined interface. It requires coordination with the owner or developer of your invoicing software, including agreement on data mapping, access, and how the systems handle errors.
File upload starts with an export from your existing system. Your team prepares a file in the agreed format and follows a batch workflow. This approach can be a practical starting point when direct system integration needs more preparation.
Manual encoding provides another option for teams working without a suitable integration or export. Discuss all three methods with ComUnion before selecting a package. Setup requirements and subscription scope should reflect your actual operations.