Workflow Builder Canvas (Threadline) is a complete visual workflow editor you can drop into any product. Drag Trigger, Action, Condition, Delay, Transform and End nodes onto an infinite pan/zoom canvas, wire them together by dragging from ports, and edit every node in an inspector panel. Everything is plain HTML, CSS and JavaScript - double-click index.html and it runs.

A built-in mock engine evaluates branches against a sample payload, runs small math and string expressions, fills {{templates}} and simulates delays, then the editor replays the run step by step with highlighted nodes and edges and a live log. The engine is isolated in one file (js/engine.js), so connecting your own backend means replacing a single function. Nothing is sent over the network.

It includes three sample workflows, undo/redo, autosave to localStorage, JSON import/export, a minimap, dark and light themes, keyboard control (including a no-mouse way to connect nodes) and a responsive mobile layout with drawers. Honest scope: it is a front-end editor and simulator, not an execution server.