Event Relays
Event Relays in Salesforce are a feature that forwards platform events from Salesforce to Amazon EventBridge, letting AWS-hosted systems consume Salesforce events natively.
Definition
Event Relays in Salesforce are a feature that forwards platform events from Salesforce to Amazon EventBridge, letting AWS-hosted systems consume Salesforce events natively. The relay is configured per event channel and per AWS account, with Salesforce taking responsibility for delivery, retry, and message ordering. This is how Salesforce becomes a first-class event producer in an event-driven AWS architecture without requiring custom Apex callouts or middleware.
Event Relays are part of Salesforce''s broader Platform Events and Pub Sub API story. Platform Events are publish-subscribe messages internal to Salesforce; the Pub Sub API exposes them outside via gRPC streams; Event Relays extend the model by pushing them into Amazon EventBridge for AWS-native consumption. Customers running serverless workflows on AWS (Lambda, Step Functions, EventBridge Pipes) get a clean integration path without building a polling layer.
How Event Relays push Salesforce events into AWS EventBridge
The relay model: from Platform Event to EventBridge bus
A Platform Event published in Salesforce (a custom event like Order_Placed__e or a standard one like the Change Data Capture event) gets picked up by the configured Event Relay. The relay forwards the event to a configured Amazon EventBridge bus in a specific AWS account. The event arrives at EventBridge with the original event payload and metadata; AWS consumers (Lambda functions, EventBridge rules, EventBridge Pipes) take it from there.
Configuration: per-channel, per-AWS-account
Setup, then Event Relays. Create a new Event Relay by picking the source channel (the Platform Event you want to relay) and the destination AWS account and EventBridge bus. Each relay handles one channel-to-bus pairing. Multiple relays can target different channels or different AWS accounts; they run independently.
AWS account linkage and the trust relationship
Event Relays require a trust relationship between Salesforce and the target AWS account. The customer creates an IAM role in their AWS account with permission to write to EventBridge, with Salesforce''s service principal as the trusted entity. Salesforce assumes this role to push events. The setup is one-time per AWS account; multiple relays in that account share the role.
Delivery guarantees and the retry model
Event Relays provide at-least-once delivery with automatic retry on transient failures. Salesforce retries failed deliveries with exponential backoff up to a configured period. If retries exhaust, the event is dropped (with a notification). AWS-side guarantees apply once the event lands in EventBridge: EventBridge itself has its own at-least-once semantics for downstream consumers.
Ordering and the event sequence
Events within a single Platform Event channel preserve order through the relay: if A publishes before B, A reaches EventBridge before B. Across channels there is no guarantee. Consumers needing strict cross-channel ordering must implement their own sequencing logic, typically using event timestamps or sequence numbers.
Event schema and AWS-side consumption
Salesforce sends events to EventBridge with a defined schema: source field set to a Salesforce identifier, detail-type set to the event channel name, detail object holding the event payload. AWS-side rules and Lambda functions can filter on these fields. EventBridge Schema Registry can capture the schema for IDE auto-complete and type-safe consumer code.
Use cases that suit Event Relays
Real-time AWS-side processing of Salesforce events: a Lambda function that updates a data warehouse when a Salesforce record changes; a Step Functions workflow triggered by a Salesforce opportunity stage change; an EventBridge rule that forwards critical events to PagerDuty. Event Relays are the right answer when the consumer lives in AWS; for non-AWS consumers, use the Pub Sub API directly.
How to configure an Event Relay from Salesforce to AWS EventBridge
Configuring an Event Relay involves work on both sides: Salesforce defines the relay; AWS prepares the EventBridge bus and IAM role. The setup is one-time per AWS account and per channel.
- Create the target EventBridge bus in AWS
In AWS EventBridge, create a custom event bus (or use the default) in the target account and region. Note the bus ARN; you will reference it in Salesforce.
- Create the IAM role with EventBridge permissions
Create an IAM role with a policy granting events:PutEvents on the target bus. Set the trust policy to allow Salesforce''s service principal to assume the role. Salesforce''s Setup page provides the exact principal value.
- Open Event Relays in Setup
Setup, then Event Relays. Click New Event Relay. The wizard walks you through the configuration.
- Configure the relay
Pick the source Platform Event channel. Provide the destination AWS account ID, region, EventBridge bus name, and the IAM role ARN. Save.
- Activate the relay
By default, a new relay is inactive. Click Activate. Salesforce starts pushing events from the channel to EventBridge. The first publish should arrive within seconds.
- Verify delivery
Publish a test Platform Event from Salesforce (via the API or a flow). In EventBridge, check the bus or set up a debugging rule that captures all events. Confirm the event arrives with the expected schema.
The Platform Event channel to relay. One per relay; for multiple channels, create multiple relays.
The account holding the target EventBridge bus.
The EventBridge bus that receives events. Can be default or custom.
The role Salesforce assumes to push events. Must grant events:PutEvents.
- Event Relays require Salesforce Pub Sub API entitlement. Smaller editions may not include it; check before designing around the feature.
- The IAM role trust policy must include Salesforce''s service principal exactly. Copy from the Setup page, not from prior documentation, because the principal value can change.
- Failed deliveries after retry exhaust are dropped. Critical events should use additional resilience: have the AWS consumer write to a dead-letter queue or implement a polling fallback.
- Ordering is guaranteed within a channel, not across channels. Architectures that need strict cross-channel order must add sequencing logic.
Trust & references
Straight from the source - Salesforce's reference material on Event Relays.
- Event Relays OverviewSalesforce Help
About the Author
Dipojjal Chakrabarti is a B2C Solution Architect with 29 Salesforce certifications and over 13 years in the Salesforce ecosystem. He runs salesforcedictionary.com to help admins, developers, architects, and cert/interview candidates sharpen their fundamentals. More about Dipojjal.
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