External interaction patterns

Patterns for waiting on or interacting with systems and actors outside the Workflow, including external APIs, human decisions, and scheduled delays.

Polling External Services

Strategies for polling external resources with varying frequencies: frequent, infrequent, and periodic patterns.

Long-Running Activity

Long-running Activities report progress via heartbeats and enable resumption after failures with cancellation support.

Approval

Human-in-the-loop Workflows that block until external approval decisions are made. Uses Signals to capture approval data with metadata.

Delayed Start

Creates Workflows immediately but defers execution until a specified delay expires. Fits one-time scheduled operations and grace periods.

Webhooks

Three patterns for durable webhook integration: receive inbound webhooks via Signals, fire delayed outbound callbacks with durable timers, and complete activities asynchronously via task tokens.