n8n

n8n is a fair-code workflow automation platform that lets you connect any app or API without writing code. You build automations by dragging nodes onto a canvas and linking them together. Each node represents an action, a trigger, or a data transformation. The editor runs in your browser, but the engine processes everything on your own infrastructure.

n8n supports over 400 integrations out of the box, including Google Sheets, Slack, PostgreSQL, and Stripe. You can also add custom nodes or use HTTP Request nodes to hit any REST API. It runs on Linux, Windows, macOS, and Docker. The core is built in TypeScript and uses a queue-based architecture for handling large workloads. Data flows through each workflow step in JSON, making it easy to transform and filter records before they reach their destination.

The project was founded by the team behind n8n GmbH and is released under a Sustainable Use License, which means free for individuals and small teams but requires a paid license for competitive commercial use. n8n is widely adopted by sysadmins and billing teams to synchronize invoicing data, reconcile payments, and trigger alerts when thresholds are crossed.