Cloud Computers for AI Agents in 2026: A Practical Comparison A developer compared seven cloud sandbox and VM providers for hosting AI agents — machine0, OpenComputer, E2B, Daytona, Modal, Fly.io Sprites, and Vercel Sandbox — testing each SDK up to the API-key check as of September 26, 2026. The comparison found isolation ranges from full KVM virtual machines to Firecracker microVMs, gVisor, and plain containers, with max session lifetimes spanning a hard 8-hour cap at OpenComputer to indefinite persistence at machine0 and Fly.io Sprites. For a 2 vCPU / 4 GB machine running flat out for an hour, machine0 costs $0.052 versus $0.378 at OpenComputer, though machine0 bills while stopped. An AI agent that only talks is cheap to host. The moment it needs to install packages, run tests, start a server, or leave a job running overnight, it needs a computer of its own. Handing it yours means giving a language model a shell on the machine that holds your SSH keys. A whole category of products now rents that computer by the second. They look alike on their landing pages, but underneath they make very different choices. machine0 gives you a full KVM virtual machine that runs until you stop it. OpenComputer caps every sandbox at 8 hours, hibernation included. E2B restores a Firecracker microVM from a memory snapshot in about 150 ms. Daytona runs plain containers unless you ask for a VM. I went through the docs, pricing pages, and SDKs of seven of them, installed each SDK, and ran the examples below up to the API-key check. All facts and prices for those seven are as of September 26, 2026. Five newer ones get a short honorable mention near the end. The running example throughout is one ordinary agent job: clone a Node.js repo, run npm test , start a dev server on port 3000, and show someone the result. Pick by lifetime first. machine0 and Fly.io Sprites give an agent a machine that persists indefinitely. OpenComputer v2 sandboxes end after a hard 8 hours. E2B, Vercel Sandbox, and Modal cap a continuous session at 24 hours on paid plans. Isolation is not uniform. machine0 and OpenComputer run KVM virtual machines, E2B, Vercel, and Sprites use Firecracker microVMs, Modal uses gVisor, and Daytona defaults to Linux containers. Of these seven, only E2B pauses every sandbox with memory intact and keeps the paused sandbox with no expiry. Daytona does it on VM sandboxes only; the rest save the filesystem. For a 2 vCPU / 4 GB machine running flat out for an hour, machine0 costs $0.052, E2B and Daytona $0.166, Modal $0.238, and OpenComputer $0.378. machine0 bills while stopped, though, and the usage-billed ones cost far less when the agent is mostly waiting on a model. Need GPUs? machine0, Daytona, and Modal have them. Need a desktop for computer use? E2B Desktop, Daytona Computer Use, or Orgo. Every product here does the same four jobs. It boots an isolated Linux machine, gives the agent a way to run commands in it an SDK call, SSH, or an MCP tool , exposes a port so a human can see the result, and decides what survives when the machine stops. The interesting differences are in how each job is done. Isolation comes in three strengths. A full virtual machine under KVM gets its own kernel and looks like a normal server, so Docker, kernel modules, and GPUs work. A Firecracker microVM is a stripped-down KVM guest built to start fast; E2B's runtime README explains that "creating" a sandbox means "restoring one, not booting a kernel", with memory pages loaded lazily on first access. Containers share the host kernel and rely on namespaces, and gVisor sits in between by intercepting system calls in a user-space kernel. Persistence is where the category splits into two camps. Persistent computers keep a disk and run until you stop them, like a VPS an agent can drive. Sandboxes are built to be created per task, used for minutes, and thrown away, with snapshots as the way back. Neither is better. A coding agent that works on one repo for a week wants the first kind. A product that runs untrusted code for thousands of users wants the second. Where each product puts the boundary between the agent's code and the host. The price column is the list rate for 2 vCPU and 4 GB running at full CPU for one hour. Where a product bills on actual usage, the real bill for an agent that spends most of its time waiting on model calls is lower. Data: machine0, E2B, Daytona, Modal, Fly.io, Vercel, and OpenComputer pricing pages, September 26, 2026. | Product | Isolation | Max lifetime | Keeps memory on pause | GPU | 2 vCPU / 4 GB, 1 h | |---|---|---|---|---|---| | machine0 | Full KVM VM | None, runs until stopped | No suspend is disk snapshot | Up to 8x H200 | $0.052 | | OpenComputer v2 | Full KVM VM | 8 h, hard | No | No | $0.378 | | E2B | Firecracker microVM | 1 h Hobby / 24 h Pro per session, resets on pause | Yes, kept indefinitely | No | $0.166 | | Daytona | Container VM optional | None, auto-stops after 15 min idle by default | VM sandboxes only | Up to 8 GPUs | $0.166 | | Fly.io Sprites | Firecracker microVM | None, sleeps when idle | While warm only | No | $0.315 usage-billed | | Vercel Sandbox | Firecracker microVM | 45 min Hobby / 24 h Pro per session | No filesystem snapshot | No | $0.341 active CPU | | Modal Sandboxes | gVisor VM in beta | 24 h | Alpha only | T4 to B300 | $0.238 | machine0 launched on Hacker News on August 18, 2026 as a YC Summer 2026 company, and it is the most traditional product here. The founder's launch post puts it plainly: "Every machine is a full KVM virtual machine, not a container or sandbox." Its FAQ says the VMs run on DigitalOcean infrastructure across five regions. You get a dedicated public IP kept across stop, replaced on suspend , SSH as user ubuntu with password login disabled, and an authenticated HTTPS URL at https://