# Open source * [Apache Pulsar](https://pulsar.apache.org/docs/en/concepts-architecture-overview/) * [NATS Streaming](https://nats.io/documentation/streaming/nats-streaming-intro/) * [NSQ](https://nsq.io/) * [Redis Streams](https://redis.io/topics/streams-intro) * [Kafka](https://kafka.apache.org/) # Cloud Service * [Google Cloud Pub/Sub](https://cloud.google.com/pubsub/) * [Amazon SNS](https://aws.amazon.com/sns/) # Features to research * Architecture * Persistence * Scalability * Fault-tolerance * Performance
