xAI shipped Grok Build in May 2026 with a feature most v0.1 agents skip: it spawns up to eight parallel subagents, each in its own Git worktree, all running real commands at once. That's serious horsepower — and eight autonomous shells on your laptop is eight times the reason to keep them off it. Here's the move: run Grok Build on its own always-on Firecracker microVM. Bring your Grok subscription, keep a persistent workspace, and let all eight subagents loose inside a box they can't escape — booting in about 124ms.
What Grok Build is
Grok Build is xAI's terminal-native coding agent, powered by grok-code-fast-1 — a model xAI built on programming content and real pull requests. The architecture is the story:
- Parallel subagents. Up to eight at once, each in its own Git worktree.
- Plan Mode by default. It proposes a step-by-step plan; you approve, comment, or rewrite it. Nothing runs until you sign off.
- MCP and
AGENTS.mdout of the box — the cross-vendor conventions Claude Code and Codex use too. - Headless mode for automation and CI pipelines.
That headless, multi-agent design is built for a box that's always on — not a laptop you close.
Why a real microVM for Grok Build
A coding agent runs bash. Grok Build runs eight of them in parallel, across worktrees, executing whatever each subagent decides — code no human reviewed. On your laptop that's the whole machine on the line, multiplied. A shared container shares the host kernel, with 200-plus known weaknesses in the stack — the wrong boundary for this much autonomy.
jurniti gives Grok Build its own Firecracker microVM — its own kernel, a KVM hardware boundary, one tenant per box. The same isolation serverless platforms use. Give it root inside its own VM and eight subagents, a runaway command, or a poisoned dependency all stay contained to that box. Reprovision and you're clean in seconds.
You keep your xAI relationship. jurniti's BYOK is architectural: authenticate with your SuperGrok or X Premium+ subscription, or paste a GROK_CODE_XAI_API_KEY. The credential lives only in your VM, traffic leaves straight for xAI, and jurniti is never in the path. No proxy, no token markup.
Grok Build runs on Starter (1 vCPU / 2 GiB) for most work; lean on many parallel subagents and a larger plan gives them room. And it's reversible: a 30-day money-back guarantee, workspace kept 7 days after cancellation.
Run Grok Build in 3 steps
By hand this is a VPS, the xAI installer, auth, a systemd unit, tmux for durable sessions, and patching for as long as you run it. jurniti runs the box; you keep the agent.
1. Pick a plan and pay
Starter is enough to start. Check out, and the provision chain runs automatically the moment payment confirms.
2. Your microVM boots with Grok Build ready
A fresh Ubuntu microVM boots with Grok Build pre-installed and on your PATH. You get an in-browser terminal — nothing to SSH into. Authenticate and go:
grok # authenticate with your Grok subscription
# or: export GROK_CODE_XAI_API_KEY=...
3. Put it to work
Hand Grok Build a task, review its plan, and let the subagents run. Your agents and commands live on the persistent home, so they survive every restart.
What people run Grok Build for
- Parallel work. Eight subagents chewing through a backlog at once — safely, in one box.
- Plan-then-execute runs. Approve the plan, walk away, come back to the result.
- Headless CI jobs. Wire Grok Build into a pipeline on an always-on box instead of your laptop.
- A pinned environment. Your
AGENTS.md, MCP servers, and commands — set up once, always there.
Snapshot a configured workspace into a template and fork it for the next project — your setup, never your credentials.
jurniti vs a laptop vs a DIY VPS
| jurniti | Your laptop | DIY VPS | |
|---|---|---|---|
| Always on | Yes | No — it sleeps | Yes |
| Isolation for parallel subagents | Firecracker microVM (KVM) | Your whole machine | Shared kernel |
| Grok login | Yours, never leaves the VM | Yours | Yours |
| Blast radius of 8 subagents | One disposable microVM | Your whole machine | Your whole server |
| Setup | Automatic · 124ms boot | Local install | Manual |
| Refund | 30-day money-back | n/a | None |
Pricing
Starter is $25/mo ($250/year, two months free) and runs Grok Build for most work. Pro is $49/mo and Max $99/mo give parallel subagents more room or add a custom TLS subdomain. Every plan includes the 30-day money-back guarantee, and your Grok subscription or API spend is separate and never marked up.
Running a different agent? See the guides for Claude Code, OpenAI Codex CLI, and Goose, or compare plans on the pricing page.