Compare event-driven architectures across AWS EventBridge, Azure Event Grid, GCP Eventarc, and OCI Events.
Output will appear here...A comparison of event-routing and orchestration services across AWS (EventBridge, SNS, SQS, Step Functions), Azure (Event Grid, Service Bus, Logic Apps), GCP (Pub/Sub, Eventarc, Workflows), and OCI (Events, Streaming, Notifications, Functions), and the max event size ceiling varies enough to actually block an architecture: AWS EventBridge/SNS/SQS all cap at 256KB, OCI Events caps at just 64KB, Azure Event Grid allows 1MB for CloudEvents, while GCP Pub/Sub allows up to 10MB per message, a workload passing moderately-sized payloads as events (rather than a pointer to the payload) may simply not fit on three of the four providers without a payload-offload pattern.
Not reliably, the max event size differs by an order of magnitude across providers (64KB OCI Events, 256KB AWS EventBridge/SNS/SQS, 1MB Azure Event Grid, 10MB GCP Pub/Sub). A payload sized for GCP Pub/Sub's 10MB ceiling would be rejected outright on OCI Events or AWS EventBridge, design for the smallest ceiling in your target provider set, or use a payload-offload pattern (store the payload, put a reference in the event) for portability.
No, OCI has no native schema registry among these services, relying on something like OCI API Gateway for validation instead. AWS (EventBridge Schema Registry), Azure (Schema Registry for Event Hubs), and GCP (Pub/Sub schema validation for Avro/Protocol Buffers) all have a native option, if schema enforcement is a hard requirement and OCI is in your provider mix, budget for building that validation layer yourself.
Conceptually similar (both let you reprocess past events) but different mechanics: EventBridge Archive and Replay works against a stored archive of past events matching a filter, while Pub/Sub's seek moves a subscription's read pointer to a timestamp or snapshot within the topic's existing retention window. Neither is a drop-in substitute for the other if you're porting a replay-dependent workflow between the two providers.
The comparison table is a static, hand-maintained dataset of feature rows grouped by category (overview, routing, messaging, reliability, pricing) with free-text search across all fields; it's a reference snapshot, not a live specs feed, verify current max event sizes and pricing directly with the provider before finalizing a cross-cloud event-driven architecture.
OCI Events' 64KB max size is easy to miss when a proof-of-concept was built and tested first on GCP Pub/Sub or Azure Event Grid, always check the target provider's specific ceiling before assuming a payload-in-event pattern will port unchanged.
EventBridge's per-event pricing ($1/million) versus Pub/Sub's per-volume pricing ($40/TiB) means the cheaper provider depends entirely on your event size and volume profile, a high-frequency-small-events workload and a low-frequency-large-events workload can favor opposite providers.
None of these four services guarantee event delivery ordering by default outside of specific configurations (Pub/Sub ordering keys, Service Bus sessions), don't assume cross-provider ordering parity without checking the specific ordering guarantee each provider's chosen service actually offers.
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