Self-hosted, turnkey ephemeral sandbox and preview environments with microVM-grade isolation and no Kubernetes

dev tool real project •• multiple requests

Developers self-hosting their infra, and people running AI-agent-generated code, want a self-hostable, turnkey way to spin up disposable environments that give an instant preview URL like a PR deploy, isolate at the microVM or gVisor level instead of plain Docker, and do not require standing up Kubernetes. The product everyone names as the gold standard is exe.dev, which is hosted SaaS only. The self-hostable open options are either Docker-isolation-only (no real boundary for untrusted agent code), Kubernetes-bound, or beta SDK-shaped runtimes, so nobody ships the SSH-in-and-it-is-there plus preview-link plus VM-isolation bundle as one self-hosted product.

builder note

The unsolved part is not the isolation runtime, microsandbox already nails libkrun. It is the boring networking glue: giving each ephemeral VM a stable preview URL with TLS and routing without dragging in a Kubernetes ingress controller. Build the on-demand reverse-proxy plus per-sandbox subdomain plus SSH-in-and-it-is-running layer on top of Firecracker or microsandbox and you have shipped what people asked for by name.

landscape (3 existing solutions)

The space is crowded with hosted SaaS (exe.dev, Modal, E2B, Daytona) and with Kubernetes-bound or SDK-shaped open source. The specific intersection HN users keep asking for, self-hosted plus turnkey plus preview URLs plus microVM or gVisor isolation plus no Kubernetes, has no obvious winner, and the demand recurs across multiple 2026 threads.

exe.dev The named gold standard (disposable VMs and devboxes for agents, by the second), but hosted SaaS only with no self-host or open-source option. It just raised a 35M dollar Series A. Commenters explicitly want a self-hosted clone.

microsandbox libkrun microVMs, self-hostable, no Kubernetes, the closest match. But it warns it is still beta software ('Expect breaking changes, missing features, and rough edges') and is shaped as an embeddable code-execution SDK, not a turnkey preview-URL and SSH-in deploy experience.

isola gVisor sandboxes, actively maintained, but requires Kubernetes and has no preview-URL deploy UX.

sources (1)

hn https://news.ycombinator.com/item?id=48388909 "I'd like something like this but using firecracker VMs. Basically, a self hosted exe.dev." 2026-06-03

sandboxpreview-environmentsfirecrackerself-hostedai-agents