Best Stream Processing Software in 2026
Updated
In short: Confluent Cloud is ranked #1 of 23 as of 4 October 2026, ahead of Esper and Feldera. The best-ranked option with a free plan is Esper. The lowest first paid tier on this page is Materialize at $0.13/mo.
When events keep arriving, stream processing tools let you transform and analyze data continuously instead of treating it as a static batch. Compared on deployment model, event-time windows, source connectors, SQL and stateful processing, and supported languages, the entries show different ways to build that work into your stack. Confluent Cloud, Esper, and Feldera are among the first entries, followed by Materialize and RisingWave. Check the free-plan and paid-from details alongside the processing features: the right balance depends on where workloads will run, how events should be handled over time, and which languages your team uses.
23 stream processing software ranked on what their makers publish — plans and prices, free tiers, platforms and the facts on their own pages.
Stream Processing Software, one module each. A lit port is something its maker publishes; 16 of the 23 on this page have a public API.
- 01 Confluent Cloud API yesOSS not on recordFREE yesDOCS 7.4$385/mo
- 02 Esper API yesOSS not on recordFREE yesDOCS 7.4Free
- 03 Feldera API yesOSS not on recordFREE yesDOCS 7.4Free
- 04 Materialize API yesOSS not on recordFREE yesDOCS 7.4$0.13/mo
- 05 Pathway Live Data Framework API yesOSS not on recordFREE yesDOCS 7.4Free
- 06 Apache Beam API yesOSS not on recordFREE yesDOCS 7.3Free
- 07 Apache Flink API yesOSS not on recordFREE yesDOCS 7.3Free
- 08 Apache Samza API yesOSS not on recordFREE yesDOCS 7.3Free
- 09 Apache Spark API yesOSS not on recordFREE yesDOCS 7.3Free
- 10 Apache Storm API yesOSS not on recordFREE yesDOCS 7.3Free
- 11 Arroyo API yesOSS not on recordFREE yesDOCS 7.3Free
- 12 Timeplus API yesOSS not on recordFREE yesDOCS 7.3$199/mo
- 13 Apache NiFi API yesOSS not on recordFREE yesDOCS 7.2Free
- 14 Hazelcast Platform API yesOSS not on recordFREE not on recordDOCS 6.9
- 15 RisingWave API yesOSS not on recordFREE not on recordDOCS 6.9$0.23/mo
- 16 Amazon Managed Service for Apache Flink API yesOSS not on recordFREE not on recordDOCS 6.7
- 17 Kafka Streams API not on recordOSS not on recordFREE yesDOCS 6.0Free
- 18 AFL++ API not on recordOSS not on recordFREE yesDOCS 5.9€1666.67/mo
- 19 Apache Kafka API not on recordOSS not on recordFREE not on recordDOCS 5.2
- 20 Siddhi API not on recordOSS not on recordFREE not on recordDOCS 5.2
- 21 Quix Streams API not on recordOSS not on recordFREE not on recordDOCS 5.1
- 22 Timely Dataflow API not on recordOSS not on recordFREE not on recordDOCS 5.0
- 23 Apache Heron API not on recordOSS not on recordFREE not on recordDOCS 4.6
Is your platform on this list?
Numbered spots on this list can be sponsored. They are labelled, and the editorial order and scores never change for payment.
Questions about this list
Which stream processing software is ranked first on Inferse?
Confluent Cloud is ranked #1 of 23 with a score of 7.4. Esper is second and Feldera third.
How many of these have a free plan?
15 of the 23 on this page publish a free plan on their own pricing pages.
Which is the cheapest paid option?
On this page, Materialize has the lowest first paid tier we found: $0.13/mo.
How is this list ranked?
Ranked on what each maker publishes, open and connectable first: a public API, open-source code, the depth of its documentation and a free tier to try it on. Model lists are sorted by the figure in their title, exactly as each provider publishes it. Paid placements never change a rank.