Runtime is part of Y Combinator

We're happy to share that Runtime is part of Y Combinator's P26 batch.

The problem

Runtime started from a specific frustration. Coding agents like Claude Code, Codex, and OpenCode are powerful enough to ship real software, but in practice, only engineers can use them safely. Everyone else on the team, product, design, marketing, ops, is either blocked entirely or running agents with no guardrails and no visibility into what's happening. The result is that most of the org still files tickets and waits, even though the tools to build already exist.

What we're building

We're building the infrastructure that closes this gap. Runtime gives engineering full control over how coding agents run: system instructions, domain allowlists, encrypted secrets that never touch the sandbox, and session-level observability across every agent interaction. And it gives everyone else a way in. Through our app builder, Slack, Linear, Jira, or GitHub, anyone on the team can spin up an environment, make changes against a production replica, and open a PR that goes through the same review process as anything else.

Why this matters

The goal is simple. When the bottleneck is no longer "who can code" but "what should we build next," the entire org moves faster. Ideas get tested in hours instead of sitting in a backlog for weeks. The people closest to the customer, the ones who actually know what needs to change, can change it.

Why YC, why now

We're already working with YC scaleups and used in 40+ countries with zero ad spend. That traction, combined with what we've learned from dozens of conversations with engineering leaders, convinced us that this is the right problem at the right time.

Runtime started as an open-source CLI for sandboxed agent deployments, and that repo is where the name comes from. Being part of YC means we can keep investing in the OSS project while building the commercial product on top of it. We get to move faster, build with the best founders in the batch, and get Runtime into the hands of more teams while the window is wide open.

Come build with us

We're hiring our founding team. If you want to build at the intersection of sandboxed environments, background agents, and developer infrastructure, or if you want to build content and community in SF, reach out.

For early customers, we're giving the forward-deployed CTO treatment. We'll personally set up your environments and make sure your team is shipping within the first week.

Get 500 free credits and try Runtime today at runtm.com.

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