Temporal vs Inngest vs Vercel Workflow in 2026: Picking a Durable Engine

Durable execution engines went from "interesting infra pattern" to "the only sane way to build AI agents and long-running background work" in 2026. Temporal, Inngest, and Vercel Workflow are the three I keep seeing in production. Here is how they actually compare after running real workloads on all three.