Inside Workflow DevKit: How framework integrations work

This post details the pattern behind Vercel Workflow DevKit (WDK) framework integrations. It explains the two-phase pattern: build-time generation of workflow handlers using SWC compiler plugins (client, step, and workflow modes) and runtime exposure of these handlers as HTTP endpoints via framework-specific routing. It highlights how WDK adapts to different frameworks like SvelteKit (Vite-based) and Express/Hono (HTTP server-based, using Nitro), including handling framework-specific request object conversions and implementing Hot Module Replacement.