BVisor – An Embedded Bash Sandbox, 2ms Boot, Written in Zig

In plain words

BVisor is an SDK and runtime that executes bash commands in lightweight sandboxes on the host machine without requiring remote services, VMs, or containers. Built with Zig and powered by seccomp syscall interception, it boots sandboxes in 2 milliseconds from user-space without special permissions. The tool isolates process visibility, blocks privilege escalation, and keeps filesystem changes isolated per sandbox using copy-on-write. It supports filesystem operations, file I/O, and runs complex binaries like Python at near-native speed. BVisor is designed for developers who need secure local command execution.

written from the facts on this page · September 2026

From the sources

Embedded bash sandbox for agents, inspired by gVisor - butter-dot-dev/bVisor

bVisor is an SDK and runtime for safely executing bash commands locally, without the need for remote sandboxes or local VMs/containers. Inspired by gVisor , bVisor runs programs directly on the host machine, providing isolation by intercepting and virtualizing Linux syscalls from userspace. Unlike gVisor, bVisor is built to run directly in your application, spinning up sandboxes in ~2 milliseconds. This makes it ideal for ephemeral tasks commonly performed by LLM agents, such as code execution or filesystem operations. Status : bVisor is an early proof-of-concept and should not yet be used in production. If you detect any discrepancies between bVisor's behavior and the linux kernel, please…from github.com

In the maker’s words, at launch

bVisor is an SDK and runtime for safely executing bash commands directly on your host machine. We built it on the belief that "sandbox" doesn't need to mean shipping off to remote sandbox products, or spinning up local VMs / containers. Sometimes, you just want to run that bash command locally. bVisor boots a…

• 
  Drop – a rootless Linux sandbox with gVisor support30d ago · droprun.sh · ▲193

  Drop: a rootless Linux sandbox for developers. It isolates coding agents and third-party packages while preserving your work environment.

• 
  Sub-millisecond VM sandboxes using CoW memory forkingMar 2026 · github.com · ▲311

  I wanted to see how fast an isolated code sandbox could start if I never had to boot a fresh VM. So instead of launching a new microVM per execution, I boot Firecracker once with Python and numpy already loaded, then snapshot the full VM state. Every execution after that creates a new KVM VM backed by a `MAP_PRIVATE` mapping of the snapshot memory, so Linux gives me copy-on-write pages automatically. That means each sandbox starts from an already-running Python process inside a real VM, runs the code, and exits. These are real KVM VMs, not containers: separate guest kernel, separate guest…

• 
  Sandboxd – speed up your bash/zshrc by lazy-loading the slow bits2016 · github.com · ▲13

  speeds up your bashrc by running (slow) setup commands on the fly - benvan/sandboxd

• 
  Tiny VM sandbox in C with apps in Rust, C and ZigDec 2025 · github.com · ▲196

  Minimalist, dependency-free virtual machine sandbox for microcontrollers and other resource-constrained devices. Single C file, no dynamic memory allocations, asynchronous design, pure C99 - ringtailsoftware/uvm32

• 
  Wiser – minimal hypervisor boots Linux VM, written in C2021 · github.com · ▲136

  :racehorse: Extremely minimal vmm for linux written in C. Hopefully someday will spin linux-vm for you. - flouthoc/wiser

• 
  Zerobox – Sandbox any command with file, network, credential controlsMar 2026 · github.com · ▲141

  I'm excited to introduce Zerobox, a cross-platform, single binary process sandboxing CLI written in Rust. It uses the sandboxing crates from the OpenAI Codex repo and adds additional functionalities like secret injection, SDK, etc. Watch the demo: https://www.youtube.com/watch?v=wZiPm9BOPCg Zerobox follows the same sandboxing policy as Deno which is deny by default. The only operation that the command can run is reading files, all writes and network I/O are blocked by default. No VMs, no Docker, no remote servers. Want to block reads to /etc? zerobox…

• 
  /dev/null▲484

  a social network for devs

  Dev tools · 3d ago · dev-null.sh

• 
  Whiteboard (YC W26) – an open-source IDE for thoughtful software design▲423

  open-source IDE for thoughtful software design. Contribute to devdotfast/whiteboard development by creating an account on GitHub.

  Dev tools · 28d ago · github.com

• 
  Reladraw – A diagram language where you decide where to place things▲411

  Contribute to reladraw/reladraw development by creating an account on GitHub.

  Dev tools · 26d ago · github.com

• 
  OpenBot▲362

  Grok Bot alternative: free, local, open-source, multiplayer

  Dev tools · 23d ago · openbot.run

• 
  Talanoa▲346

  Hi HN, I’m a fullstack developer, and honestly, I’ve lost count of how many side projects I’ve worked on over the years. But one idea kept coming back to me: a different kind of email client. It first came to me in 2014: “What if we could handle emails more like conversations?” Every year, I’d revisit this concept in my “Build Notes.” Ten years later, no one had built exactly what I had in mind — so I finally decided to do it myself. That’s how Talanoa was born. I wanted something focused on people, not timelines. I was tired of marking messages as unread just to remember to reply later, or…

  Dev tools · 21d ago · talanoa.email

• 
  CoreSpeed▲332

  One MCP for everything your agents need: apps, memory, tools

  Dev tools · 28d ago · corespeed.io

• 
  Rork Max▲1,428

  Best AI for iOS apps. Website that replaces Xcode

  Life & fun · Feb 2026 · rork.com

• 
  happycapy▲1,365

  The agent-native computer, for the rest of us

  AI · Feb 2026 · happycapy.ai

• 
  SuperX▲897

  All-in-one growth OS for serious 𝕏 creators

  AI · Feb 2026 · superx.so

• 
  KiloClaw▲868

  Hosted OpenClaw. No Mac mini required.

  Dev tools · Feb 2026 · kilo.ai

• 
  Lovon AI Therapy▲801

  Feel closer and have more fun with your partner every day!

  AI · Feb 2026 · lovon.app

• 
  I spent 3 years reverse-engineering a 40 yo stock market sim from 1986▲721

  Hello my name is Ben Ward for the past 3 years I have been remastering the financial game Wall Street Raider created by Michael Jenkins originally on DOS in 1986. It has been a rough journey but I finally see the light at the end of the tunnel. I just recently redid the website and thought maybe the full story of how this project came to be would interest you all. Thank you for reading.

  Work · Feb 2026 · wallstreetraider.com