Make messaging implementation choices a compact draft shortlist

content/topics/messaging-implementations-and-hosting/topic.md

@@ -2,7 +2,7 @@
 id: 'b34b3eca-ea1a-4d87-94f5-ee46a11192f2'
 title: 'Messaging implementations and hosting'
 status: 'draft'
-summary: 'Name an engine or cloud service that fits the messaging model and operational constraints.'
+summary: 'Narrow an interview scenario to five messaging options using workload, platform, and one tradeoff.'
 iconKey: 'queue'
 domains:
   - 'system-design'
@@ -11,94 +11,21 @@ childTopicIds: []
 relatedTopicIds: []
 ---
 
-## Narrow the candidates
+![Worker-job choices: SQS Standard for a managed AWS queue, accepting duplicates and out-of-order delivery; RabbitMQ for an existing platform or its broker features, accepting setup and capacity decisions.](./queue-choices.svg)
 
-- **Background jobs:** RabbitMQ; AWS SQS; GCP Pub/Sub with workers sharing a subscription
-- **Independent event subscribers:** RabbitMQ exchanges + queues; AWS SNS + SQS; GCP Pub/Sub
-- **Retained log and replay:** Apache Kafka; AWS MSK; GCP Managed Service for Apache Kafka
-- **Existing JMS broker integration:** ActiveMQ Classic; Amazon MQ for ActiveMQ Classic
+![Fan-out choices: SNS plus SQS on AWS needs a queue and policy per subscriber application; GCP Pub/Sub uses service-specific APIs and subscription policies and also supports workers sharing one subscription.](./fanout-choices.svg)
 
-These are starting points, not exclusive capabilities. Choose the model first, then check ordering, replay, failure handling, and existing platform constraints.
+![History and replay: Apache Kafka, self-managed or hosted, still needs partitioning, retention, and consumer-progress design.](./replay-choice.svg)
 
-## Engines: self-managed or hosted
+> **Thumbnail jobs:** compare **SQS Standard** and **RabbitMQ** first; **Pub/Sub** is a GCP option. Retained-history or replay requirements give Kafka a stronger reason.
 
-### RabbitMQ
+**Broker setup ≠ self-managed hosting.** Defining queues, routing rules, and retries also applies to a hosted broker. Self-management adds servers, upgrades, availability, and recovery.
 
-- **Fit:** job queues and routed pub/sub through exchanges and queues.
-- **Tradeoff:** topology, durability, acknowledgements, and capacity still need design. RabbitMQ also supports streams; it is not limited to queues.
-- **Hosting:** run it yourself or use a managed provider, including Amazon MQ.
-
-### ActiveMQ Classic
-
-- **Fit:** existing JMS applications and broker/protocol compatibility.
-- **Tradeoff:** select and operate the broker topology and verify client/version compatibility.
-- **Hosting:** self-managed or Amazon MQ. Specify **Classic**; do not assume Amazon MQ hosts Artemis.
-
-### Apache Kafka
-
-- **Fit:** retained event history, replay, and the Kafka processing ecosystem.
-- **Tradeoff:** partition keys, retention, consumer lag, and ordering remain design responsibilities even with managed hosting.
-- **Hosting:** self-managed, Amazon MSK, Google Cloud Managed Service for Apache Kafka, or another provider.
-
-## AWS services
-
-### SQS Standard
-
-Independent jobs; no strict ordering needed.
-
-**Tradeoff:** At-least-once delivery; duplicates and out-of-order delivery are possible.
-
-### SQS FIFO
-
-Ordering within message groups and send deduplication matter.
-
-**Tradeoff:** Group design constrains parallelism; retries can still repeat business effects.
-
-### SNS + SQS
-
-Fan-out with a durable queue for each consumer application.
-
-**Tradeoff:** More queues, subscriptions, and failure policies to manage.
-
-### Amazon MQ
-
-Managed RabbitMQ or ActiveMQ Classic; engine/protocol compatibility matters.
-
-**Tradeoff:** Broker capacity and engine-specific configuration still matter.
-
-### MSK
-
-Managed Kafka and its APIs/ecosystem.
-
-**Tradeoff:** Kafka data-model and consumer responsibilities remain.
-
-**Standard and FIFO are SQS queue types, not pricing tiers.** FIFO deduplication is bounded; a received message that is not deleted can become visible again.
-
-## GCP services
-
-### Pub/Sub
-
-Managed fan-out; shared subscriptions can distribute worker jobs.
-
-**Tradeoff:** Service-specific API and subscription, retention, and ordering policies.
-
-### Managed Service for Apache Kafka
-
-Kafka APIs, tooling, and partitioned-log model are required.
-
-**Tradeoff:** Kafka partitions, retention, and consumer behavior still need design.
-
-## Who operates what?
-
-- **Self-managed engine:** your team owns provisioning, upgrades, storage, replication, monitoring, and recovery.
-- **Managed engine:** provider operates the broker infrastructure within the service contract; your team still owns topology, configuration, clients, and workload behavior.
-- **Managed service API:** no broker cluster to operate directly; accept service-specific APIs, limits, and guarantees.
+These are starting points, not exclusive capabilities. Standard is an SQS queue type; ordering requirements may lead to FIFO. Managed hosting reduces infrastructure work, not application delivery responsibilities.
 
 ## Sources
 
-- [RabbitMQ queues](https://www.rabbitmq.com/docs/queues) and [streams](https://www.rabbitmq.com/docs/streams)
-- [ActiveMQ Classic features](https://activemq.apache.org/components/classic/documentation/features)
-- [Amazon MQ engines](https://docs.aws.amazon.com/amazon-mq/latest/developer-guide/welcome.html)
-- [SQS Standard](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/standard-queues.html) and [FIFO delivery logic](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/FIFO-queues-understanding-logic.html)
-- [Amazon MSK](https://docs.aws.amazon.com/msk/latest/developerguide/what-is-msk.html)
+- [SQS Standard](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/standard-queues.html) and [FIFO delivery](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/FIFO-queues-understanding-logic.html)
+- [RabbitMQ queues](https://www.rabbitmq.com/docs/queues) and [managed RabbitMQ on Amazon MQ](https://docs.aws.amazon.com/amazon-mq/latest/developer-guide/welcome.html)
+- [SNS + SQS fan-out](https://docs.aws.amazon.com/sns/latest/dg/sns-sqs-as-subscriber.html)
 - [Google Pub/Sub versus managed Kafka](https://docs.cloud.google.com/pubsub/docs/choose-pubsub-kafka)