Subscribe to Salesforce Pub/Sub API events via gRPC to receive high-throughput Platform Events

In-depth guide

Steps

1. Connect to the Salesforce Pub/Sub API gRPC endpoint at api.pubsub.salesforce.com:7443 using a gRPC client library in your language of choice
2. Obtain a Salesforce access token and instance URL via the OAuth 2.0 JWT Bearer or Username-Password flow, then attach them as gRPC metadata headers (accesstoken, instanceurl, tenantid)
3. Call the Subscribe RPC with a SubscribeRequest specifying the topic name (e.g., /event/MyEvent__e), the replayPreset (LATEST, EARLIEST, or CUSTOM), and a numRequested value per fetch batch
4. Decode each FetchResponse: events are encoded in Apache Avro binary format using the schema fingerprint in the event; fetch the schema via the GetSchema RPC using the schemaId from the event
5. Cache schemas by schemaId to avoid a GetSchema round trip on every event — schemas are immutable once published for a given fingerprint
6. Acknowledge processed events by sending a new SubscribeRequest with the latest replayId to advance the subscription cursor and prevent redelivery