Blog — page 34 of 38
The Best E2B Alternatives in 2026
A 2026 field guide to E2B alternatives — PandaStack, Modal, Daytona, Runloop, Vercel Sandbox, Northflank, Cloudflare, and DIY Firecracker/gVisor/Kata — with a comparison table and honest 'pick this by use case' calls.
How to Run AI-Generated Code Safely: a 2026 Playbook
The model has no intent — but no judgment either. It will cheerfully run `rm -rf /`, pip-install a hallucinated package, or exfiltrate your data because a web page told it to. Here's the six-step playbook, with code, to run AI-generated code safely.
Protecting CI Secrets from Malicious Dependencies with MicroVM Isolation
Every build, your CI runner executes whatever's in package-lock.json with the enthusiasm of a golden retriever and the credentials of a root user. Here's how to run untrusted dependencies without handing them your deploy keys.
vsock vs TCP: How Should the Host Talk to a Guest?
Two ways to reach an agent inside a microVM: virtio-vsock over the hypervisor transport, or a TCP socket over the guest's virtio-net TAP. One needs no IP and no network; the other is what every HTTP tool already speaks. Here's the head-to-head, and why a control plane usually wants the servants' staircase.
Self-Hosted GitHub Actions Runners in Firecracker MicroVMs
A fork PR is a stranger handing you a script and politely asking you to run it as root. Give it a fresh microVM, register it as an ephemeral runner, let it do one job, then delete the whole machine.
Per-User Notebook Kernels: Isolating a Hosted Jupyter Product
In a hosted notebook product, every user's kernel runs arbitrary Python next to every other user's data. A shared kernel pool is a breach with a UI. Give each user their own microVM.
Giving Every Agent in a Swarm Its Own Sandbox
Fan out twenty agents into one shared sandbox and you get twenty agents fighting over the same files, ports, and process table — until one of them runs rm -rf and takes the whole swarm with it. Give each its own microVM instead.
Running a Plugin Marketplace Without Getting Owned
Every plugin marketplace is a supply chain you don't control. Review passed v1.0; nobody re-reads v1.1. The fix isn't better review — it's running each plugin invocation in a Firecracker microVM that a malicious update can't escape.
PandaStack vs Runloop for AI Coding Agents
Runloop offers persistent Devboxes for AI coding agents; PandaStack is open-source Firecracker sandboxes you can self-host. An honest, founder's comparison.
Firecracker vs AWS Lambda: Same Engine, Different Boundary
This isn't Firecracker versus a competitor. Lambda is built on Firecracker — AWS wrote the VMM specifically to run it. So the real question is: the open-source primitive you control, or the managed product that inherits AWS's opinions on top of it?
The Anatomy of a Sub-200ms MicroVM Create
179ms p50 is not a single event — it's eight stages, each shaved to single- or low-tens of milliseconds. This is the itemized bill: where every millisecond of a snapshot-restore create actually goes, and the idea that makes each line cheap.
Firecracker MMDS: Passing Config Into a MicroVM Safely
How do you hand a fresh microVM its identity — a token, a config blob, per-tenant secrets — without baking it into the image or shipping it over the network? Firecracker's MMDS gives the guest a link-local HTTP endpoint the host controls. Here's the mechanism, the v1-vs-v2 hardening, and why 169.254.169.254 is the most attacked IP you never memorized.
VM escape attacks explained: what they are and why microVMs shrink the target
A VM escape is guest code breaking out through the hypervisor onto the host — the exploit-dev equivalent of a hole-in-one: rare, celebrated, and mostly theoretical for your threat model. Here's where the shots historically land, why they cluster in device emulation, and how a microVM makes the target much smaller on purpose.
Best MicroVM Platforms in 2026: An Honest Buyer's Guide
You've decided you want microVM-grade isolation — a separate kernel per workload. Now what do you build on? The honest field: raw VMMs (Firecracker, Cloud Hypervisor, QEMU, Kata) vs managed platforms (PandaStack, E2B, Modal, Fly, Runloop, Northflank).
How to Build a Remote Code Execution API Safely
An endpoint that runs arbitrary user code is a remote code execution vulnerability you shipped as a feature. The only sane boundary is a fresh microVM per request.
Give Your AI Coding Agent a Sandbox to Run PR Checks
Your AI reviewer clones a PR and runs its test suite. The PR is a stranger's code. Running it on your CI host — where the deploy keys live — is how secrets leak. Give each PR its own microVM.
A MicroVM for Every LLM Tool Call: Per-Request Isolation
A tool call runs code the model wrote, shaped by whatever was in the context window. The safe unit of isolation isn't a shared worker — it's a fresh microVM per invocation.
Firecracker vs Kata vs gVisor: three isolation models
gVisor intercepts syscalls, Kata wraps a container in a real VM, Firecracker boots a minimal microVM. All three exist because someone decided a shared host kernel is a load-bearing hope, not a boundary. Here's how to pick.
PandaStack vs Blaxel: agent sandbox platforms compared
Blaxel is an AI-agent infrastructure platform; PandaStack is an open-source Firecracker microVM sandbox. An honest, hedged, side-by-side comparison.
The Firecracker security model: how a microVM actually contains untrusted code
"It runs in a VM" isn't a security model — it's one layer of one. Here's the full stack Firecracker actually stacks to run untrusted, multi-tenant code: KVM, a minimal device model, the jailer, seccomp on the VMM itself, and memory-safe Rust. Two walls, on purpose.
Kill Cold Starts with microVM Snapshotting: Warm Starts Without a Warm Pool
A warm pool is you paying the cloud to keep computers awake in case someone shows up. microVM snapshotting flips it: freeze a booted VM once, restore it copy-on-write on demand, and pay ~0 while nobody's home.
Running MCP Tools Safely: Sandbox the Execution
Isolating the MCP server process is only half the job. The tool calls themselves — run_code, run_shell, filesystem ops — do the actual work, and a single injected call can do real damage. Here's how to spawn a per-call microVM around the execution and hand structured results back to the model.
WebAssembly vs Firecracker for Untrusted Code
WASM asks "may I?" before every syscall; Firecracker hands you a whole Linux guest behind a hardware wall. For untrusted code the real question isn't which is safer — it's which can run the workload at all.
Isolating Batch Jobs and Queue Workers with MicroVMs
A shared worker runs every tenant's job in one process, on one box, sharing one /tmp. One bad job — an OOM, a fork bomb, a leaked file descriptor — is a murder-suicide pact with every other job on the machine. Give each job its own microVM instead.