# S2

9 Hacker News commenters recommended S2 and 3 criticized it, November 2025 to November 2026. It was recommended in 5 of 13 months.

**Verdict:** 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.

## Why people recommend it

- Durable storage backed by object storage (3 comments): "Having literally everything backed by object storage is The Dream, so this makes a lot of sense." ([source](https://news.ycombinator.com/item?id=46734703)) "it has the durability of object storage rather than just local" ([source](https://news.ycombinator.com/item?id=46732559)) "unlimited streams with the durability of object storage" ([source](https://news.ycombinator.com/item?id=46198915))
- Stream-per-session model fits agents (2 comments): "a model based on stream-per-session, durable and serverless fits the use case well" ([source](https://news.ycombinator.com/item?id=46544497)) "S2 is great for agent session-level streams" ([source](https://news.ycombinator.com/item?id=46544356))
- Simpler API with bottomless storage (2 comments): "S2 gives you a simpler API, bottomless storage" ([source](https://news.ycombinator.com/item?id=46735553)) "a model based on stream-per-session, durable and serverless fits the use case well" ([source](https://news.ycombinator.com/item?id=46544497))

## What people warn about

- Open-source version is single-node only (2 comments): "S2-lite is pretty cool, but it's single-node only and built on SlateDB" ([source](https://news.ycombinator.com/item?id=49433602)) "S2 is not open source, and the OSS version is S2-Lite, which is single-node only" ([source](https://news.ycombinator.com/item?id=49426247))
- Not fully open source or self-hostable (2 comments): "I'm not seeing full self-hosting yet, and "Book a call" link is an instant nope for many techies." ([source](https://news.ycombinator.com/item?id=46202822)) "S2 is not open source, and the OSS version is S2-Lite, which is single-node only" ([source](https://news.ycombinator.com/item?id=49426247))

## Alternatives hackers recommend

- [Apache Kafka](https://hackerapproved.com/p/apache-kafka.md): 53 recommend
- [NATS](https://hackerapproved.com/p/nats.md): 34 recommend
- [Redpanda](https://hackerapproved.com/p/redpanda.md): 17 recommend
- [RabbitMQ](https://hackerapproved.com/p/rabbitmq.md): 13 recommend
- [PostgreSQL LISTEN/NOTIFY](https://hackerapproved.com/p/postgresql-listen-notify.md): 13 recommend

## Cite as

Hacker Approved, "S2", https://hackerapproved.com/p/s2-lite/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).