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microsandboxvsvercel sandbox

pick vercel sandbox when you want managed sandboxes attached to vercel, with active-cpu billing and runtime-updatable firewall rules. [1][2][3] pick microsandbox when the same boundary must start locally and embed in your application.

vercel sandbox and microsandbox both give untrusted code a dedicated guest kernel. vercel runs each sandbox in a firecracker microvm on its managed platform. [1] this is not a container-versus-vm comparison.

vercel's strongest fit is platform integration. its sandbox sdk connects to vercel projects, observability, active-cpu billing, and a network firewall that can update rules while a sandbox runs. [1][2][3] its firewall also documents cidr fallback for non-tls traffic, credential transforms, and request proxy filtering. [2][4]

microsandbox begins with the runtime on your machine and keeps that sdk shape across deployment paths. choose vercel when its managed platform is where the workload belongs. choose microsandbox when local execution and runtime ownership are requirements. private beta. access is by request.

microsandbox
local + cloud
vercel sandbox
managed firecracker microvms [1]
isolation
hardware-isolated microvm · its own kernel
firecracker microvm · dedicated kernel [1]
environment
oci images from standard registries
built-in runtimes or imported oci images [1]
network firewall
by default, sandboxes can reach the public internet. private, host-local, link-local, and metadata destinations are blocked. egress can be reduced to an allowlist or disabled entirely. in the cloud, the non-public block cannot be lifted, even by you.
runtime-updatable domain and cidr rules; cidr covers non-tls traffic [2]
credential and proxy rules
credentials are destination-bound. the sandbox works with a placeholder; the real value is substituted host-side into supported intercepted outbound requests, only for destinations on your allow-list. an approved destination still receives the real credential and could reflect or misuse it, so scope your allow-lists accordingly.
header transforms plus beta request forwarding and matcher-based filtering [4]
billing model
local execution is free · private beta pricing is published
active-cpu billing excludes time waiting on i/o [3]
where it runs
local runtime · private beta. access is by request.
vercel's managed platform [1]
programming model
embeddable runtime · rust, typescript, python, go, and cli
sandbox sdk and cli connected to a vercel project [1]
license
apache 2.0
managed service with open-source sdk and cli [1]
pick vercel sandbox

choose vercel sandbox when

  • the workload belongs inside a vercel project and its managed operations. [1]
  • active-cpu billing fits sessions that spend significant time waiting on i/o. [3]
  • you need firewall rules that can change while the sandbox runs. [2]
  • you want its request proxy and matcher-based credential filtering. [4]
pick microsandbox

choose microsandbox when

  • the actual microvm runtime must run during local development.
  • you want to embed the runtime instead of binding the workload to a hosted project.
  • rust, python, or go is part of your native sdk surface.
  • one sdk. one api. local or cloud is a config change, not a rewrite.
  • contact us to evaluate running microsandbox inside your own environment.

01

moving from vercel sandbox

the sandbox lifecycle stays familiar: choose an image, create an isolated environment, run commands, collect output, and stop it. the integration change is where those calls land. vercel targets its managed service. [1] microsandbox can execute the same application flow locally.

keep vercel-specific firewall transforms, request proxying, active-cpu billing, and project operations visible in the migration plan. [2][3][4] those are real platform capabilities, not generic microvm features.

see microsandbox pricing

common questions

is microsandbox a vercel sandbox alternative?

yes for running untrusted code in an own-kernel microvm. vercel is the managed option attached to its platform. [1] microsandbox is the local-first runtime you can embed.

does vercel sandbox use firecracker?

yes. vercel documents a firecracker microvm for each sandbox. [1]

can vercel sandbox filter network traffic?

yes. its firewall supports domain and cidr rules, live updates, cidr fallback for non-tls traffic, and beta request-proxy matchers. [2][4]

how does vercel sandbox handle credentials?

vercel documents header transforms that add or replace credentials on matching outbound requests. it also documents beta filtering by path, method, query, or headers. [4]

can vercel sandbox run locally?

the sdk can be called from outside vercel, but the sandbox runs on vercel's managed platform. [1] microsandbox runs the microvm itself on the local machine.

run it locally.

put the boundary on your own machine before you choose anything else.

run it locally