Workflow Messaging Patterns

These patterns cover how external callers communicate with running Workflows — starting them on demand, sending data in, reading results back, and collecting streams of events. They build on Temporal's Signals and Updates.

Patterns in This Section

Signal with Start

Starts a Workflow and delivers a Signal in a single atomic operation. If the Workflow already runs, it receives the Signal directly.

Request-Response via Updates

Sends a request into a running Workflow and receives a validated result on the same call, using an Update handler.

Event Accumulator

Collects a stream of incoming Signals into a buffer and processes them together as a batch, rather than one at a time.

Choosing a Pattern

You want to send a message without checking whether the Workflow is running: use Signal with Start.

You need a result back from the Workflow, with validation: use Request-Response via Updates.

You receive many events and want to process them in batches: use the Event Accumulator to buffer and flush.

Related Sections

• Entity & Lifecycle Patterns — long-lived Workflows that consume these messages over time
• Distributed Transaction Patterns — Early Return builds on the Update-with-Start mechanism