TL;DR

Castari is hosting infrastructure for agents that need more than an API call. Run cast deploy and your agent gets a secure sandbox, auto-scaling endpoint, and full observability.

Public beta is live today.

https://youtu.be/2fpCTj051kY

The problem

Serious agents aren’t just “call an API and done.”

They execute code, hit tools and browsers, run for minutes to hours, and touch sensitive systems. Every team ends up rebuilding the same fragile setup:

• homegrown agentic harnesses
• stitched-together sandboxes/microVMs/containers/queues
• logs and traces scattered everywhere
• hacky snapshots and suspect secret handling

So:

• every agent needs its own mini-runtime
• debugging one run is detective work
• adding a new agent feels like starting a new infra project

Deploying agents that work great locally turns into wrangling infrastructure.

The problem

Serious agents aren't chatbots. They execute code, call tools, touch filesystems, and run for hours. They need a computer.

But there's no good way to put them in production. You end up stitching together containers, queues, and compute layers — rebuilding the same infrastructure every team rebuilds. The agent works on your laptop. Getting it to work reliably for users takes weeks.

We hit this ourselves. We built an AI consumer app to 2M+ members while at RunPod (scaled to $100M revenue). The hardest part was never the model — it was the harness. Every time we shipped a new agent, we were rebuilding sandboxing, scaling, secrets, and monitoring from scratch.

What we built

Castari wraps your agent in a secure sandbox and gives you back a production endpoint.

npm install -g @castari/cli
cast login
cast deploy

Your agent now has:

• Secure sandbox — full isolation. Your agent can safely execute code, use browsers, and access filesystems
• Auto-scaling endpoint — scales with demand, no capacity planning
• Observability — trace every tool call, decision, and output in real time
• Multi-model support — Claude, OpenAI, xAI, open source. Your code stays the same
• Zero lock-in — remove Castari and your agent still runs on vanilla Claude Agent SDK

How we're different

Most tools give you primitives — a sandbox API, a container runtime, a compute layer. You still stitch it together yourself.

Castari wraps around your agent. You define it declaratively, we manage the lifecycle: provisioning, versioning, execution, scaling, teardown. You write agent logic, not infrastructure code.

What's next

• Better tracing and observability — debug agent behavior in production, not after the fact
• Higher sandbox concurrency limits — run more agents in parallel
• Forever-running sandboxes — agents that stay alive indefinitely

Why we’re working on this

While I was leading the FDE team at RunPod:

• Built and shipped AI infrastructure and agents for Fortune 500s and fast-growing startups
• Watched the same loop repeat: agent works in a notebook → weeks disappear into infra glue → nobody trusts the system, production release gets delayed (over and over again).

Additionally, while @Cambree Bernkopf and I scaled our AI consumer app to 2m+ users, our biggest issues were getting our agents to work reliably in production.

The pattern is clear: agents deserve a first-class runtime, the way frontends got one.

Castari is our bet that:

• Sandboxing & safety should be built-in, not bolted on
• Going from “prototype” to “production-safe” should be one config file, not a quarter-long project
• AI teams should ship agents, not infrastructure.

Try it

Docs: docs.castari.com

Website: castari.com

CLI: npm install -g @castari/cli

Or email jacob@castari.com — happy to get you deployed.

— Jacob & Cambree