# Workflow messaging patterns

> Patterns for sending data into running Workflows and receiving responses or triggering behavior changes.

Patterns for sending data into running Workflows and receiving responses or triggering behavior changes.

- [Signal with Start](/design-patterns/signal-with-start): Starts a Workflow when Signaling it if it does not already exist. If already running, it receives the Signal directly.
- [Request-Response via Updates](/design-patterns/request-response-via-updates): Synchronous request-response with validation. Updates modify state and return results directly.