Celery is an asynchronous task queue/job queue based on distributed message passing. It is focused on real-time operation, but supports scheduling as well.
Cost / License
- Free
- Open Source
Platforms
- Mac
- Windows
- Linux
- Python
Apache Pulsar is described as 'Distributed, open source pub-sub messaging and streaming platform for real-time workloads, managing hundreds of billions of events per day' and is an app. There are more than 10 alternatives to Apache Pulsar for a variety of platforms, including Linux, Windows, Mac, Web-based and SaaS apps. The best Apache Pulsar alternative is RabbitMQ, which is both free and Open Source. Other great apps like Apache Pulsar are Zenaton, Amazon Simple Queue Service, Eclipse Mosquitto and ØMQ.
Celery is an asynchronous task queue/job queue based on distributed message passing. It is focused on real-time operation, but supports scheduling as well.
Zeplo lets developers add retry, delay, queue and schedule to HTTP endpoints without setting up Redis, RabbitMQ or SQS. Just prefix any HTTP endpoint with zeplo.to/ and the request is queued.




Zeplo is the most popular commercial alternative to Apache Pulsar.
Pub/Sub works as a messaging middleware for traditional service integration or a simple communication medium for modern microservices.