| Message Ordering | Per Queue (FIFO) | Per Queue (FIFO) | Per Partition (strong within partition) | Limited | Per Topic, Partitioned Topics |
| Message Delivery Guarantees | At-Least-Once | At-Least-Once, Exactly-Once | At-Least-Once, Exactly-Once | At-Least-Once, At-Most-Once (configurable) | At-Least-Once, Exactly-Once (via Pulsar Functions) |
| Message Persistence | Durable Queues | Persistent Stores | Durable, High Performance (Commit Log) | Optional, In-Memory by default | Durable with BookKeeper, Multi-tiered Storage |
| Scalability | Moderate, Cluster Support | Moderate, Master-Slave, Network of Brokers | High (Horizontally Scalable) | High (Horizontally Scalable) | Very High (Horizontally Scalable, Geo-replication) |
| Throughput | High | High | Very High | Very High | Very High, Comparable to Kafka |
| Latency | Low to Moderate | Moderate | Low | Very Low | Low (Tail Latency Optimization) |
| Fault Tolerance | Mirrored Queues, Clustering | Master-Slave, KahaDB, JDBC stores | Distributed, Replication | Clustered, In-Memory with Persistence Option | Distributed, Geo-replication, Multi-DC Support |
| Ease of Use | Easy to moderate | Easy to moderate | Complex | Easy | Moderate (Complex for advanced features) |
| Community Support | Strong, Open-Source | Strong, Open-Source | Very Strong, Open-Source | Growing, Open-Source | Growing, Open-Source, Active Community |
| Use Case Fit | General Purpose | General Purpose | Streaming, Event Sourcing, Log Aggregation | Lightweight Messaging, Real-Time, IoT | Streaming, Event Sourcing, Pub/Sub, Geo-distributed |
| Cost | Open-Source | Open-Source | Open-Source | Open-Source | Open-Source |
| Integration | Broad Integration Support | Broad Integration Support | Broad Integration Support | Lightweight, Less Integrations | Extensive (supports Kafka API, MQTT, AMQP, etc.) |
| Security | TLS, SASL, Plugins | TLS, SSL | TLS, SASL | TLS | TLS, Authentication Plugins, Role-Based Access Control |
| Message Acknowledgement | Explicit Acknowledgement, Nack Support | Acknowledgement, Redelivery Support | Offset Commit (Consumer Acknowledgement) | Automatic or Manual Acknowledgements | Ack, Nack, Redelivery Policies |
| Message Prioritization | Yes | Yes | No | No | Yes (Supported via Topic Policies) |
| Complex Routing | Yes (Exchange Types) | Yes (Virtual Destinations) | Limited to Topics/Partitions | Limited to Topics/Subjects | Yes (Topics, Partitions, Namespaces) |
| Monitoring & Management Tools | RabbitMQ Management Plugin, Prometheus | JMX, Web Console | Kafka Manager, Prometheus, JMX | Prometheus, NATS Dashboard | Pulsar Manager, Prometheus, Grafana |
| Client Libraries | Extensive (Java, Python, Go, etc.) | Extensive (Java, C++, etc.) | Extensive (Java, Python, Go, etc.) | Limited, but growing (Go, Python, etc.) | Extensive (Java, Python, Go, C++, etc.) |
| Transaction Support | Yes | Yes | Yes (Atomic Writes, Exactly Once) | Limited | Yes (Support for Transactions) |
| Operational Overhead | Moderate | Moderate | High | Low | Moderate to High (depending on features used) |
| Message Retention | Configurable, TTL Support | Configurable, TTL Support | Configurable (Log Retention) | Limited | Configurable, Tiered Storage |
| Cluster Management | Requires Plugins, Complex Setup | Network of Brokers | Built-in, Zookeeper/RAFT | Built-in | Built-in, Distributed, ZooKeeper |
| Dead Letter Queues (DLQs) | Supported | Supported | Not Native (Can be Configured) | Supported (JetStream) | Supported |
| TTL Support | Yes | Yes | Yes | Limited | Yes |
| Replayability | Limited | Limited | Native (Replay from Offset) | Supported (JetStream) | Native Support, Replay from Storage |
| Schema Validation | Limited (Can be added) | Limited (Can be added) | Supported via Confluent Schema Registry | No (Can be added) | Supported (Pulsar Schema Registry) |
| Stream Processing | Limited (Can be added) | Limited (Can be added) | Native Support (Kafka Streams) | No | Native Support via Pulsar Functions |