Compare event/messaging services (EventBridge, Event Grid, Pub/Sub) across providers.
Last verified: May 2026
Serverless event bus that connects applications using events from AWS services, SaaS apps, and custom sources. Supports schema discovery, content-based filtering, and archive/replay.
Fully managed event routing service with built-in support for Azure services, third-party services, and custom topics. Supports event domains for multi-tenant architectures.
Eventarc routes events from Google Cloud services, SaaS, and custom sources to Cloud Run, GKE, and Workflows. Built on Pub/Sub for reliable message delivery with up to 7-day retention.
[
{
"provider": "aws",
"serviceName": "Amazon EventBridge",
"description": "Serverless event bus that connects applications using events from AWS services, SaaS apps, and custom sources. Supports schema discovery, content-based filtering, and archive/replay.",
"maxMessageSize": "256 KB",
"maxRetention": "24 hours (default retry period); unlimited with archive",
"deliveryGuarantee": "At-least-once",
"filteringCapability": "Content-based filtering on event fields (prefix, suffix, numeric, exists, anything-but, IP address matching)",
"schemaRegistry": true,
"dlqSupport": true,
"eventSources": 200,
"pricingModel": "Per event published ($1.00/million custom events)",
"freeAllowance": "AWS service events are free; no free tier for custom events",
"pricePerMillionEvents": 1
},
{
"provider": "azure",
"serviceName": "Azure Event Grid",
"description": "Fully managed event routing service with built-in support for Azure services, third-party services, and custom topics. Supports event domains for multi-tenant architectures.",
"maxMessageSize": "1 MB",
"maxRetention": "24 hours (retry period); dead-letter to Blob Storage for longer",
"deliveryGuarantee": "At-least-once",
"filteringCapability": "Event type filtering, subject prefix/suffix filtering, advanced filtering on data fields (number, string, bool operators)",
"schemaRegistry": false,
"dlqSupport": true,
"eventSources": 700,
"pricingModel": "Per operation ($0.60/million operations after free tier)",
"freeAllowance": "100,000 operations/month free",
"pricePerMillionEvents": 0.6
},
{
"provider": "gcp",
"serviceName": "Eventarc + Cloud Pub/Sub",
"description": "Eventarc routes events from Google Cloud services, SaaS, and custom sources to Cloud Run, GKE, and Workflows. Built on Pub/Sub for reliable message delivery with up to 7-day retention.",
"maxMessageSize": "10 MB (Pub/Sub message size limit)",
"maxRetention": "7 days (Pub/Sub message retention); 31 days with topic retention",
"deliveryGuarantee": "At-least-once (exactly-once available on Pub/Sub pull subscriptions)",
"filteringCapability": "Pub/Sub subscription filters (attribute-based); Eventarc trigger filters on event type, resource, and service",
"schemaRegistry": true,
"dlqSupport": true,
"eventSources": 130,
"pricingModel": "Pub/Sub: $40/TiB ingested (~$0.04/million 1KB events); Eventarc: no additional charge beyond Pub/Sub and audit logs",
"freeAllowance": "First 10 GB/month of Pub/Sub messaging free",
"pricePerMillionEvents": 0.04
}
]Your platform team is choosing an event bus for a new event-driven architecture targeting 50M events/month at avg 2 KB each. The estimator runs the volume through each: EventBridge $50/month, Event Grid $30/month, Pub/Sub $23/month. Cost favors Pub/Sub. But the team is on AWS; using Pub/Sub means cross-cloud egress (~$45/month outbound) and adding GCP IAM into the auth model. EventBridge wins for total cost-of-ownership ($50 vs $68) AND keeps the architecture in one cloud's IAM domain.
The Multi-Cloud Event Bus Compare tool compares event routing and messaging services across AWS (EventBridge), Azure (Event Grid), and GCP (Pub/Sub Eventarc). It covers event filtering, delivery guarantees, dead-letter handling, pricing models, and integration with other cloud services. The tool helps you evaluate event-driven architecture options across cloud providers.
The compare tool normalizes pricing across the three event bus models: EventBridge ($1/M events), Event Grid ($0.60/M operations after free tier), and Pub/Sub (per-TiB ingestion + delivery, with 10 GiB free). It applies your event volume and size to each pricing model, surfaces feature differences (filtering language, schema registry, dead-letter, multi-region), and outputs side-by-side monthly cost plus feature-fit score.
EventBridge's content-based filtering is the most powerful of the three by a wide margin. You can match on numeric ranges, prefix/suffix, exists, anything-but, and IP CIDR. This lets you put one Bus and dispatch to the right consumer entirely via filters — no router code needed. Event Grid and Pub/Sub require simpler attribute matching.
Pub/Sub's per-TiB pricing model favors larger payload events (each subscription's 1 KB minimum makes small events disproportionately expensive). EventBridge and Event Grid's per-event pricing favors small events. Match the model to your event size: small events (telemetry, signals) = EventBridge; large events (full document payloads) = Pub/Sub.
All three buses provide at-least-once delivery with retry. None provide exactly-once. Your consumers MUST be idempotent. The most common cause of duplicate processing in production isn't the event bus retrying — it's a slow consumer that ack'd late and got the redelivery. Always design with idempotency keys.
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