Workflow DevKit is a TypeScript-based framework designed to make asynchronous applications and AI agents durable, meaning they can pause, resume, and recover execution state reliably across failures, restarts, or long-running processes. It introduces a programming model where normal async functions are enhanced with special execution semantics using "use workflow" and "use step" directives.

The framework separates application logic into two core primitives: workflows and steps. Workflow functions orchestrate multi-step processes in a deterministic way, while step functions handle side effects such as API calls, database operations, or external integrations. This separation allows workflows to be safely replayed from persisted event logs while ensuring side effects are only executed once and automatically retried if needed.

Workflow DevKit is designed for building long-running systems such as AI agents, automation pipelines, CI/CD processes, and multi-day workflows like onboarding flows or background orchestration tasks. It includes built-in observability, retry handling, state persistence, and the ability to inspect or resume execution at any point.

A key innovation of the system is its compile-time and runtime transformation model, where workflow code is sandboxed for determinism while step code runs in full Node.js environments. This enables strong guarantees around reliability while still supporting real-world side effects and integrations.

Key features include:

• Durable execution for long-running TypeScript workflows
• "use workflow" and "use step" execution model
• Automatic state persistence and resumability
• Built-in retries, logging, and observability
• Designed for AI agents, pipelines, and async orchestration systems

Common use cases include:

• Building AI agents with long-running memory
• Orchestrating multi-step backend workflows
• Handling async business processes (payments, onboarding, approvals)
• Creating resilient automation systems that survive failures or restarts

Workflow DevKit is developed by the team behind Vercel’s workflow ecosystem and is positioned as a foundational tool for building reliable, stateful backend and AI systems in TypeScript.