Cloud Sandbox for Coding Agents
REBYTE.AI
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Engineering 2026-02-03 by Rebyte Team

Cloud Sandbox for Coding Agents

Isolation, persistence, security, parallelism, and access from anywhere.

We built our own cloud sandbox for coding agents. Here's why.

Concurrent Isolation in the Cloud Cloud VM 1 Code Agent Task A Add auth flow VM 2 Code Agent Task B Fix billing bug VM 3 Code Agent Task C Write API tests VM 4 Code Agent Task D Refactor DB layer Each VM runs independently. No conflicts. True parallelism.

1. True Isolation

The old approach was git worktrees on a local machine. Run two agents on the same codebase and they step on each other. Port 3000 is already in use. Environment variables bleed across. One agent installs a package that breaks the other's dependencies.

True isolation means each task runs in its own VM. Five tasks? Five VMs. They can't conflict because they can't see each other.

2. Forever Persistence

Coding agents and serverless functions both run in the cloud. But they have dramatically different workloads.

A serverless function handles a request in 30 seconds and disappears. A coding agent spends 20 minutes writing a feature—reading files, running tests, fixing bugs, iterating. When the function returns, everything is gone. That's fatal for agents.

Our sandboxes persist forever. Close your browser, come back next week. The VM is still there. Files, git history, installed packages—all preserved.

This isn't just convenient. It's essential.

3. Code Agents Can Go Wild

Someone opens a pull request with a hidden prompt injection. Your agent reads it, and the injected instructions tell it to package your entire source code and POST it to an external server. The agent complies—it has shell access and can run curl.

On your local machine, the blast radius is everything: your SSH keys, cloud credentials, access to internal services.

Cloud sandboxes enforce network policies at the VM level. GitHub? Allowed. npm registry? Allowed. Random external server? Blocked. Defense at the infrastructure layer.

4. Maximum Parallelism

Cloud sandboxes let you run as many agents as you want, simultaneously. Ten tasks? Ten VMs, all running in parallel. You're no longer bottlenecked by your local machine. This maximizes token throughput from the language model—every agent working at full speed, at the same time.

5. Access From Anywhere

Your development environment lives in the cloud. Start a task from your laptop, check progress from your phone, review results from a different computer. No more "I left that running on my work machine."

We're releasing the iOS version of Rebyte soon. Stay tuned.

Every Rebyte task runs in its own cloud VM. True isolation. Forever persistence. Network policies. Maximum parallelism. Accessible from anywhere. That's why we built our own sandbox.