Billy is a native Mac app for freelancers and small businesses who want to keep their invoicing simple, local, and under their own control. It runs entirely offline — no accounts, no cloud sync, no third-party servers. All your data is stored in plain JSON files directly on your machine, which means you own it completely and can move, back up, or archive it however you like. Creating and managing invoices is straightforward: Add your clients, set your line items, and style the output to match your brand. Billy gives you control over colors, fonts, and layout, so the invoices you send actually look like they came from you. When it comes to compliance, Billy meets the EU standard EN 16931 and the German XRechnung specification, and has been tested through the official KoSIT validator — so the documents you generate hold up wherever they need to. No lock-in. No dependencies. Just an opinionated little app that helps you send beautiful, compliant invoices and stay on top of your paperwork. Terms of Use: https://usebilly.app/terms