https://ilham25.github.io/Recent content on Iruha Devhttps://ilham25.github.io/images/og-default.pnghttps://ilham25.github.io/images/og-default.pngHugoen-usSat, 11 Apr 2026 14:55:52 +0700https://ilham25.github.io/posts/workflow-engine-n8n-works/Sat, 11 Apr 2026 14:55:52 +0700https://ilham25.github.io/posts/workflow-engine-n8n-works/<h2 id="introduction">Introduction</h2> <p>I&rsquo;ve been using n8n for quite some time now and couldn&rsquo;t help wondering how it works under the hood, so I decided to build a minimal working version of the engine myself. This post covers how the engine handles execution order, the pluggable node system, expression evaluation, and the diamond merge pattern.</p> <p>You can find the full source code on <a href="https://github.com/ilham25/workflow-ts">GitHub</a>.</p> <h2 id="what-is-a-workflow-engine">What is a Workflow Engine?</h2> <p>Basically a workflow engine is just a graph where it has 2 or more nodes that have individual functions like “fetch this URL” or “check this condition”. These connections between nodes is what define the data flow.</p>