S2
Shares rank 8 of 19 message brokers by recommenders
Developers use S2 for durable event streams backed by object storage, with a simple API and per-session streams for agents. Critics note the open-source S2-lite is single-node only.
Developers use S2 for durable event streams backed by object storage, with a simple API and per-session streams for agents. Critics note the open-source S2-lite is single-node only.
12 people gave an opinion
- recommend it
- 9
- criticize it
- 3
- approval share
- 75%
Recommended in 5 of 13 months
- November 2025: not recommended
- December 2025: recommended
- January 2026: recommended
- February 2026: not recommended
- March 2026: not recommended
- April 2026: not recommended
- May 2026: not recommended
- June 2026: not recommended
- July 2026: not recommended
- August 2026: recommended
- September 2026: recommended
- October 2026: recommended
- November 2026: not recommended (month in progress)
Why it doesn’t carry the badge
- 9 people recommend itNeeds 10 or more, not met.
- 3 recommenders for every criticNeeds 2 to 1 or better, met.
- Recommended in 5 of 13 monthsNeeds 4 or more, met.
The same three rules apply to every product, and the badge can’t be bought. How the badge works
What people say about it
The reasons people give, with the number of comments that give each one. Open a reason to read what they said.
Why people recommend it
Each mark is one comment
Durable storage backed by object storage
“Having literally everything backed by object storage is The Dream, so this makes a lot of sense.”
Comment from 23 Jan 2026 in “Show HN: S2-lite, an open source Stream Store” “it has the durability of object storage rather than just local”
Comment from 23 Jan 2026 in “Show HN: S2-lite, an open source Stream Store” “unlimited streams with the durability of object storage”
Comment from 8 Dec 2025 in “Jepsen: NATS 2.12.1” Stream-per-session model fits agents
“a model based on stream-per-session, durable and serverless fits the use case well”
Comment from 8 Jan 2026 in “Show HN: Pydantic-AI-stream – Structured event streaming for pydantic-AI agents” “S2 is great for agent session-level streams”
Comment from 8 Jan 2026 in “Show HN: Pydantic-AI-stream – Structured event streaming for pydantic-AI agents” Simpler API with bottomless storage
“S2 gives you a simpler API, bottomless storage”
Comment from 23 Jan 2026 in “Show HN: S2-lite, an open source Stream Store” “a model based on stream-per-session, durable and serverless fits the use case well”
Comment from 8 Jan 2026 in “Show HN: Pydantic-AI-stream – Structured event streaming for pydantic-AI agents”
What people warn about
Each mark is one comment
Open-source version is single-node only
“S2-lite is pretty cool, but it's single-node only and built on SlateDB”
Comment from 25 Aug 2026 in “Show HN: PicoMQ – Durable Streams over HTTP, on object storage” “S2 is not open source, and the OSS version is S2-Lite, which is single-node only”
Comment from 24 Aug 2026 in “Show HN: PicoMQ – Durable Streams over HTTP, on object storage” Not fully open source or self-hostable
“I'm not seeing full self-hosting yet, and "Book a call" link is an instant nope for many techies.”
Comment from 9 Dec 2025 in “Jepsen: NATS 2.12.1” “S2 is not open source, and the OSS version is S2-Lite, which is single-node only”
Comment from 24 Aug 2026 in “Show HN: PicoMQ – Durable Streams over HTTP, on object storage”
Other message brokers people recommend
The four most recommended other message brokers, with the same counts for each, so you can compare like for like. The tick on each bar marks the 2 to 1 line the badge needs.
| Product | Recommend | Criticize | Approval | Months | Owned | Badge |
|---|---|---|---|---|---|---|
| Apache Kafka | 53 | 55 | 49% | 12 | — | — |
| NATS | 34 | 16 | 68% | 9 | 7.5 yrs3 owners | Approved |
| Amazon SQS | 18 | 14 | 56% | 8 | — | — |
| Redpanda | 17 | 4 | 81% | 7 | — | Approved |
| S2This page | 9 | 3 | 75% | 5 | — | — |
What people said
14 of the 18 comments that mention it, newest first. Each links to the original comment.
“we designed around stateful backend processes capable of constantly flushing multi-tenant objects”
“One alternative worth looking at is S2”
“S2-lite is pretty cool, but it's single-node only and built on SlateDB”
“S2 is not open source, and the OSS version is S2-Lite, which is single-node only”
“S2 gives you a simpler API, bottomless storage”
“Your documentation needs improvement. It proudly mentions the alphabet soup of technologies you use, but it leaves me completely baffled”
“Having literally everything backed by object storage is The Dream, so this makes a lot of sense.”
“Yes, this can be a good building block for broadcasting data streams.”
“Adding a database, multiple components, and Kubernetes to the equation seems like massively overengineering.”
“it has the durability of object storage rather than just local”
“a model based on stream-per-session, durable and serverless fits the use case well”
“S2 is great for agent session-level streams”
“I'm not seeing full self-hosting yet, and "Book a call" link is an instant nope for many techies.”
“unlimited streams with the durability of object storage”
Counts come from 1,795,640 Hacker News comments, November 2025 to November 2026. How we count. Report a mistake.