Automate Your Invoicing with Claude Code + n8n + a REST API

The average freelancer spends 5-8 hours per month on admin tasks that a computer could handle in seconds: sending payment reminders, classifying expenses, generating reports. These tasks aren't difficult. They just shouldn't require your attention. Here's how I automated 80% of my business admin with three tools: an ERP with a REST API ( Frihet ), an AI assistant (Claude Code), and a workflow automator (n8n). No coding required. The Three Pieces Your ERP - Where invoices, clients, expenses live. The critical requirement: it must have a REST API and webhooks.