We built a <60ms, open-source alternative to E2B using RustVMM and KVM
Over the past few months, as we scaled our internal AI Agents, we hit a dead end: Running LLM-generated arbitrary code in Docker is basically running naked on security due to container escape risks. But using full traditional VMs takes minutes to boot and eats too much memory to support high-density concurrency. We loved the developer experience of SaaS sandboxes on the market, but they are closed-source, expensive, and have too high a barrier to entry for self-hosting. So, our team decided to build our own. After months of grinding, using RustVMM and KVM, we built a blazing-fast,…
We built a <60ms, open-source alternative to E2B using RustVMM and KVM launched on April 22, 2026 with 7 votes, #1,538 of 21,248 launches that month and more than 75% of that year's launches.
What it does
Instant, Concurrent, Secure & Lightweight Sandbox for AI Agents. - TencentCloud/CubeSandbox
In the maker’s words, at launch
Over the past few months, as we scaled our internal AI Agents, we hit a dead end: Running LLM-generated arbitrary code in Docker is basically running naked on security due to container escape risks. But using full traditional VMs takes minutes to boot and eats too much memory to support high-density concurrency. We…
Does a similar job
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npm i -g hotcellAug 2026 · github.com · ▲97Hi HN! Sina here. i wanted to share this open source project (apache 2.0) that i've been working on for the past month or so. it's called hotcell and it lets you create/pause/manage sandboxes on any device (your laptop, linux vm, bare metal). i've tested it against various benchmarks that i found on computesdk (https://www.computesdk.com/benchmarks/sandboxes/) as well as the one shared by dax (cofounder of open code) on twitter recently (link to his original thread and my reply https://x.com/sinasanm/status/2078158598996443346) and…
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