Workflow Development Kit (vercel.com)

Vercel’s Workflow Development Kit (WDK) is an open-source TypeScript framework that makes durability a language-level feature, turning ordinary async functions into long-lived, resumable workflows with two simple directives ("use workflow" and "use step"). Steps are compiled into isolated API routes; inputs, outputs and events are recorded so executions can be deterministically replayed after crashes or deployments. Steps automatically persist progress and retry on failure, workflows can sleep for minutes to months without consuming resources, and webhooks let workflows pause until external callbacks arrive — no manual queues, schedulers, or state machines required. WDK is designed for portability and observability: a World abstraction lets the same code run locally (Local World), on Vercel, or on other runtimes via custom Worlds (Postgres World reference and community implementations exist), avoiding vendor lock‑in. Everything in a run is logged and visible via API, CLI and Web UI for real-time tracing and metrics. For the AI/ML community, WDK removes a major operational burden for long-running agents, RAG pipelines and multi-step data processing — you can write familiar async JavaScript and get durable, retryable, observable workflows out of the box, simplifying production-grade orchestration of intelligent systems.