s2.dev YC Application

Fall 2025Active

s2.dev went through Y Combinator in the Fall 2025 batch as a B2B company. Below: what the company does, who founded it, and its application to YC, reconstructed question by question in the real YC form.

YC batch: Fall 2025
Industry: B2BInfrastructure
Team size: 5
Status: Active
Launched: 2025

Founders

Shikhar BhushanCo-founder and CEO
Stephen BaloghCo-founder and CTO
Dwarak Govind ParthibanCo-founder

What s2.dev does

S2 is an API for durable streams. We make working with streaming data dead simple and reliable. The more we worked on data systems, the more we felt like there was a missing building block. The seamless experience of object storage simply did not exist for durable streams - so we set out to fix that! S2 reimagines streams as an unlimited and access-controlled web resource. Like if Kafka and S3 had a baby. - Building agents? Use granular streams to persist context in real time, make workflows auditable, and coordinate between agents. - Publishing fast-moving data? Streams support high fanout and can be accessed directly over the internet, so they are a great fit for broadcasting real-time feeds. - Sandboxing? Emit to per-instance streams, and read history or live events just as easily. - Local-first and multiplayer experiences? Propagate updates reliably and efficiently. Stop dealing with clusters, and start streaming.

s2.dev's YC application, reconstructed

Y Combinator application

s2.dev, Fall 2025 batch. The real form questions, answered from public data.

Founders2
Company7
Progress7
Idea4
Equity3
Curious2
Batch Preference1

Company

Company name

s2.dev

Describe what your company does in 50 characters or less.

API for unlimited, durable, real-time streams

What is your company going to make? Please describe your product and what it does or will do.

We built s2.dev to be an API that treats streams like durable, unlimited web resources. You can think of it as if Kafka and S3 had a baby. It makes streaming data easy, reliable, and accessible via the internet without managing clusters. Our product lets developers persist real-time context, coordinate workflows, and broadcast live data with high fanout. It's designed for teams building agents, real-time publishing, sandboxing, or multiplayer/local-first apps.

Where do you live now, and where would the company be based after YC?

We live in San Francisco, CA, and plan to keep the company based here after YC.

Explain your decision regarding location.

We picked San Francisco because it's where we live and where much of our early user base and engineering talent are. Staying local keeps us close to necessary resources and partners.

21 more answers in the full application

Founders, Progress, Idea, Equity, Curious, Batch Preference are in the full version. Create a free account to open it in YC Insights, next to every other YC batch.

See full application

Frequently Asked Questions

Is this the real s2.dev YC application?

No. Y Combinator keeps submitted applications private. This is a reconstruction: the real YC form questions, answered from s2.dev's public data (launch notes, founder backgrounds, product description). It shows how a company like s2.dev would present itself to YC, not the text they submitted.