Durable Functions extend Next.js capabilities by enabling long-running tasks without timeouts or managing queues and state. They power core features such as integrations, email scheduling, or AI workflows. Teams at Resend and Mintlify have built their backend workflow parts on top of Next.js using Durable Functions. These functions are composed of triggers and steps, which manage the state over time and overcome timeouts. Flow Control features like rate limiting, priority, or throttle configuration help control how runs span in time and avoid reaching the rate limit of third-party APIs.