Audience
Businesses, freelancers and sole traders in Germany that need to issue e-invoices (XRechnung, ZUGFeRD)
About Coretool
Coretool is a browser-based invoicing application for German businesses, freelancers, sole traders, tradespeople, and small service businesses. Users can create and manage quotes and invoices, including XRechnung and ZUGFeRD e-invoices, track customers, send payment reminders, and organize appointments. The app supports GiroCode QR codes, digital quote signatures, and validation of e-invoice documents through its REST API. API-based workflows can connect with automation tools such as Make, Zapier, and n8n; availability of some platform-specific modules may depend on approval. Calendar feeds can be added to Google, Apple, or Outlook calendars. The optional Kalkulations-Assistent supports project estimates, material and labor calculations, and quote creation. Coretool runs in a web browser without local installation. Its free plan allows three invoices per month; Solo costs €9/month plus VAT and can be canceled monthly.