Vercel Sandbox vs Replit
Vercel Sandbox is an API for short runs of untrusted or agent-written code: your program starts a Firecracker microVM, runs commands in it, and stops it. Replit is an AI app builder where a person describes an app, Replit Agent writes it, and Replit hosts it.
The companies and products
Vercel Sandbox
Vercel is a cloud platform for web apps and agents, and Vercel Sandbox is its product for running untrusted or agent-written code in isolated Linux microVMs.
Each sandbox is a Firecracker microVM with its own kernel, started from a Vercel image, your own OCI image, or a saved snapshot. You drive it with the JavaScript or Python SDK or the sandbox CLI: run commands, move files, open ports, and set network rules. It is aimed at code interpreters, app builders, test runs and agent tools, and Vercel's docs say it is not meant to run nonstop.
Replit
Replit is an AI app builder and hosting platform: you describe an app in chat, Replit Agent writes it, and Replit publishes it.
You work in a browser workspace where Replit Agent sets up the project, writes the code, tests it and fixes problems, with system packages managed by Nix. When the app is ready you publish it as an Autoscale, Static, Scheduled or Reserved VM deployment, with Postgres and object storage next to it. It is built for people and teams who want a working app, not for programs that need to create many machines by API, so this page compares the parts where the two overlap.
Which use cases each one fits
For each use case, Battleships prices every sandbox provider on the same workload and sorts them from the cheapest monthly bill up. “22nd cheapest of 345” means 21 of the other 344 providers run that workload, with every feature it needs, for less. “With limits” means the provider runs it but misses something, so it is listed after every full match. Open a use case for its whole ranking and what each provider misses.
| Use case and its workload | Vercel Sandbox: price rank | Replit: price rank | boat: price rank |
|---|---|---|---|
| Software factory 100 at once · 4 vCPU / 8 GB · 2,200 sessions of 8 h a month A software factory starts and steers many agents from code; Vercel cuts sessions at 24 hours, and Replit's outside entry point drives Replit Agent one app at a time. | 244th of 367, with limits $3,351 a month | 181st of 367, with limits $2,000 a month | 3rd cheapest of 367 $634 a month |
| Always-on AI employees 50 machines 24/7 · 2 vCPU / 4 GB Neither fits an always-on assistant well: Vercel stops each session after 24 hours, and on Replit it means a Reserved VM that bills all month. | 257th of 366, with limits $3,657 a month | 202nd of 366, with limits $2,033 a month | 5th cheapest of 366 $657 a month |
| Code interpreter bursts 100 at once · 1 vCPU / 2 GB · 200,000 sessions of 1 min a month Short code bursts suit Vercel Sandbox best: it fits fully, bills CPU only while code runs, and ranks 22nd, while Replit is a web host and only a compromise here. | 22nd cheapest of 345 $216 a month | 228th of 345, with limits $146 a month | 186th of 345, with limits $2,000 a month |
| Sandboxes for your users 300 at once · 2 vCPU / 4 GB · 30,000 sessions of 23 min a month Vercel Sandbox fits sandboxes for your users and ranks 15th, while each Replit machine is a published app; boat ranks first for the same work. | 15th cheapest of 361 $1,267 a month | 233rd of 361, with limits $825 a month | Cheapest of 361 $209 a month |
| RL rollouts 1,000 at once · 2 vCPU / 4 GB · 1,000,000 sessions of 3 min a month Vercel Sandbox ranks 3rd for many short parallel rollouts thanks to fast starts and high concurrency; Replit does not publish how many machines can run at once. | 3rd cheapest of 360 $15,761 a month | 258th of 360, with limits $4,226 a month | 34th of 360, with limits $2,000 a month |
| Agent evals 250 at once · 4 vCPU / 8 GB · 15,000 sessions of 20 min a month | 69th cheapest of 364 $1,508 a month | 265th of 364, with limits $685 a month | 10th cheapest of 364 $200 a month |
| CI runners 40 at once · 8 vCPU / 16 GB · 6,000 sessions of 12 min a month CI jobs that build containers need Docker, which Vercel Sandbox and boat have and Replit's Nix-based environments do not document. | 107th cheapest of 377 $1,144 a month | 275th of 377, with limits $425 a month | 4th cheapest of 377 $86 a month |
| 24/7 dev boxes 1 machine 24/7 · 4 vCPU / 8 GB A Replit workspace is a fine place to code by hand, while a Vercel sandbox restarts every 24 hours; boat keeps one machine up with its disk. | 276th of 368, with limits $145 a month | 165th of 368, with limits $109 a month | 18th cheapest of 368 $26 a month |
| Computer-use agents 50 at once · 4 vCPU / 8 GB · 20,000 sessions of 15 min a month Vercel Sandbox has no desktop, and Replit's VNC pane shows a desktop to a person with no API for an agent; boat streams a 60fps desktop with a computer-use API. | 235th of 369, with limits $952 a month | 190th of 369, with limits $619 a month | 6th cheapest of 369 $200 a month |
| Browser-use agents 50 at once · 2 vCPU / 4 GB · 30,000 sessions of 10 min a month | 259th of 367, with limits $486 a month | 229th of 367, with limits $317 a month | 7th cheapest of 367 $200 a month |
| Scraping & bots (startup scale) 50 at once · 1 vCPU / 2 GB · 100,000 sessions of 3 min a month | 277th of 346, with limits $468 a month | 234th of 346, with limits $217 a month | 6th cheapest of 346 $90 a month |
| Mass scraping & bots (undetectable) 1,000 at once · 1 vCPU / 2 GB · 3,000,000 sessions of 2 min a month | 234th of 338, with limits $9,960 a month | 150th of 338, with limits $4,378 a month | 71st of 338, with limits $1,800 a month |
| Parallel red teaming 200 at once · 2 vCPU / 4 GB · 5,000 sessions of 30 min a month | 283rd of 360, with limits $554 a month | 208th of 360, with limits $215 a month | 2nd cheapest of 360 $200 a month |
| GPU eval jobs 10 at once · 8 vCPU / 32 GB · 500 sessions of 30 min a month | Can't run it | Can't run it | Can't run it |
| macOS agents 5 at once · 4 vCPU / 8 GB · 1,000 sessions of 20 min a month | Can't run it | Can't run it | Can't run it |
Key features
| Feature | Vercel Sandbox | Replit | boat |
|---|---|---|---|
| Kind of product | Sandbox API: microVMs your code starts with the JavaScript or Python SDK or the CLI | AI app builder with browser workspaces and app hosting | Sandboxes you create, stop and fork by API, SDK or CLI |
| Isolation | Firecracker microVM with its own kernel | Not documented; the security page says strong logical separation between users | Full VM with its own kernel on dedicated AMD Ryzen 9 9950X hosts |
| Longest session | 24 hours on Pro and Enterprise, 45 minutes on Hobby; a resumed sandbox starts its processes over | A Reserved VM runs continuously and bills a fixed monthly price | No cap on paid plans; stopping a sandbox ends the bill |
| Saving files | Filesystem snapshot on stop, billed per GB a month and kept 30 days after last use | Workspace files and Agent checkpoints; published apps should not rely on their filesystem | Snapshot every minute while running and on stop; a stopped sandbox costs nothing |
| Docker inside | Yes, with sudo | Not documented; system packages come from Nix | Yes, with root and systemd |
| Nested virtualization | No | Not documented | Yes, /dev/kvm (Android emulator, VMs) |
| Custom images | Your own OCI images from a Dockerfile, via Vercel Container Registry | Environments set up with Nix packages | Named snapshots (templates), shareable by code; no Dockerfile builds |
| Coding agents | Claude Code, Codex, OpenCode and pi preinstalled; you start them as commands | Replit Agent, which an MCP client can also drive (create, update, ask, publish) | Claude Code, Codex, OpenCode, pi and more, with an API to prompt, steer and stream events |
| Desktop and computer use | None; headless Linux only | VNC pane that streams a desktop to your browser; no computer-use API | 60fps desktop and Chromium, computer-use and browser-control APIs, embeddable stream |
| Reaching the machine | Public URLs for up to 15 ports, no built-in auth; no raw TCP or public IP | Published apps on HTTPS and custom domains; SSH into the workspace on paid plans | HTTPS URLs for up to 50 ports, token-protected; raw TCP; dedicated IPv6 or IPv4; SSH |
| Egress rules | Allow-all, deny-all or a domain and CIDR allowlist, changeable while running | No egress allowlist | No provider-side allowlist; firewall inside the VM |
| Keys kept outside the sandbox | Credentials brokering injects headers for any HTTPS domain you allow | Replit manages keys for OpenAI, Anthropic, Google and OpenRouter models; other keys are app secrets | Credentials proxy for model providers and any HTTPS API; switch a credential to another account when one runs out |
| Hosting that sleeps when idle | No wake on request | Autoscale starts on the first request and goes idle after 15 minutes, costing nothing while idle | No wake on request; you stop and resume sandboxes yourself |
| Regions | 19 regions across the US, Europe, Asia, South America, Africa and Australia | Published apps in North America, Europe, Asia, South America or Australia; data mainly in the US | EU only: Germany, Finland, France |
Every feature Battleships tracks (43)
| Feature | Vercel Sandbox | Replit | boat |
|---|---|---|---|
| Full VM (own kernel) | Yes | Yes | Yes |
| Docker inside | Yes | No | Yes |
| Nested virtualization | No | No | Yes |
| Root | Yes | Not published | Yes |
| Systemd | Not published | No | Yes |
| Desktop GUI | No | Yes | Yes |
| Browser | No | No | Yes |
| Computer-use API | No | No | Yes |
| SSH | No | Yes | Yes |
| Persistent disk | Yes | Yes | Yes |
| Pause/resume | Yes | No | Yes |
| Automatic snapshots | Yes | Yes | Yes |
| Fork/clone | Yes | Yes | Yes |
| Live fork (no pause) | Yes | No | Yes |
| Memory fork | No | No | No |
| Custom image (Docker or snapshot) | Yes | Yes | Yes |
| ≥24 h sessions | Yes | Yes | Yes |
| Idle auto-stop | No | Yes | No |
| Wake on request | No | Yes | No |
| HTTPS preview URLs | Yes | Yes | Yes |
| Raw TCP inbound | No | Not published | Yes |
| Public IPv4 | No | No | No |
| Egress allowlist | Yes | No | No |
| Secret proxy | Yes | Yes | Yes |
| Secret proxy for any API | Yes | No | Yes |
| Preinstalled agents | Yes | Yes | Yes |
| Agent harness API | No | Yes | Yes |
| MCP server | Yes | Yes | No |
| GPU | No | No | No |
| Windows | No | No | No |
| Arm64 | No | Not published | No |
| Self-hosting | No | No | No |
| BYOC | No | No | No |
| Open source | No | No | No |
| Scoped API keys | Not published | Not published | Yes |
| Spend limits | Yes | Yes | Yes |
| Usage per sandbox (API) | No | Yes | Yes |
| Audit logs | Not published | Yes | No |
| SSO | Yes | Yes | No |
| SOC 2 | Yes | Yes | No |
| HIPAA | Yes | No | No |
| EU data residency | Yes | Yes | Yes |
| Zero data retention | Not published | Not published | Yes |
Performance
On StarSling's Node.js build-and-test benchmark at 4 vCPU / 8 GB, boat did 26.69 runs per second and Vercel Sandbox did 12.96, so boat finished about twice as many runs in the same time. Replit is not in that benchmark, so there is no comparable number for it. This measures CPU speed only, not start time.
Node.js build-and-test loop at 4 vCPU / 8 GB, higher is better. Measured with the open hpc-sandbox-benchmarks suite. Replit has no published run in this suite yet, so there is no like-for-like number to compare.
Pricing in five scenarios
Each bill is priced from the providers' public price lists by the open Battleships engine, with the cheapest plan that runs the scenario.
| Scenario | Vercel Sandbox, a month | Replit, a month | boat, a month |
|---|---|---|---|
| One coding agent, workdays 4 vCPU / 8 GB, 50 GB disk, 8 hours a day, 22 days a month, files kept between days | $57 · Pro | $122 · Pro $100 (annual) · with limits | $20 · $20/mo |
| One agent that never stops 4 vCPU / 8 GB, 50 GB disk, running 24/7 all month | $236 · Pro · with limits | $122 · Pro $100 (annual) · with limits | $26 · $20/mo |
| 50 agents in parallel 50 machines of 4 vCPU / 8 GB at once, 8-hour sessions, 1,100 sessions a month, Docker inside | $2,884 · Pro | $1,330 · Pro $1,000 (annual) · with limits | $317 · $20/mo × 3 seats |
| Sandboxes for your users 2 vCPU / 4 GB, 30,000 sessions of 10 minutes a month, up to 300 at once | $828 · Pro | $403 · Pro $250 (annual) · with limits | $200 · $100/mo × 2 seats |
| 1,000 short jobs at once 2 vCPU / 4 GB, 1,000 at once, 3 minutes each, 200,000 jobs a month | $3,152 · Pro | $825 · Pro $1,000 (annual) · with limits | $2,000 · $2000/mo · with limits |
Vercel Sandbox: Vercel charges for CPU only while your code uses it, but for memory the whole time the sandbox runs, plus a small fee per sandbox created and a monthly fee per GB of snapshots. The $20 Pro credit is shared with your other Vercel usage.
Replit: Replit plans (Core $20, Pro from $100) turn into monthly credits for Agent work and hosting. A Reserved VM has a fixed monthly price per size and bills busy or idle; Autoscale bills only while it serves requests.
Replit: boat charges a flat price per size, per second, only while the machine runs; a stopped sandbox costs nothing. Plans start at $20 a month, and all of the fee is usage credit.
Limits in those scenarios
Replit is marked as not a fit in every scenario because it is an app platform: each always-on machine is a published Reserved VM, an agent that works only on workdays still pays for the whole month, and how many can run at once is not published. Vercel Sandbox fits four of the five scenarios, but for one agent that never stops it ends each session at 24 hours and running processes start over. For 1,000 short jobs at once Vercel fits, while boat's $2,000 plan allows 600 starts an hour and queues bursts above 90 starts a minute.
| Scenario | Vercel Sandbox | Replit | boat |
|---|---|---|---|
| One coding agent, workdays | None that bite |
| None that bite |
| One agent that never stops |
|
| None that bite |
| 50 agents in parallel | None that bite |
| None that bite |
| Sandboxes for your users | None that bite |
| None that bite |
| 1,000 short jobs at once | None that bite |
|
|
Which one should you use?
Use Vercel Sandbox when
your own code runs many short bursts of untrusted code, needs a firewall it can change while running, or must run close to users outside Europe.
- Sandboxes your code starts. Useful if your app runs untrusted code: an SDK call starts a microVM, runs commands, and stops it.
- A firewall you control from outside. A running sandbox can be switched to deny-all, or to a list of allowed domains, without a restart.
- Images from your Dockerfile. Useful if you already have a Dockerfile: build it into an image and boot sandboxes straight into it.
Use Replit when
you want Replit Agent to build a web app from a description and host it for you, with a database and hosting that sleeps when idle.
- An app built and hosted for you. Useful if you want a working app from a description: Replit Agent builds, tests and publishes it for you.
- Hosting that costs nothing when idle. Useful for web apps with uneven traffic: Autoscale wakes on the first request and costs nothing while idle.
- Databases next to the app. Useful if your app needs data: Postgres and App Storage come built into each Replit app.
Where boat fits
If you are comparing these two because you want to run AI agents, boat is built for that job. Like Vercel Sandbox, your code creates the machines; unlike it, they are full VMs that can run for days with a desktop, Docker and /dev/kvm, and agents you drive from outside.
Agents can work all day
Vercel stops each session after 24 hours and the resumed sandbox starts every process over. Replit keeps a Reserved VM on, but it is one published app billed all month. boat has no session cap and saves files every minute.
A desktop and a browser built in
Without a screen an agent cannot open the app it built to check it. Vercel Sandbox is headless, so you would build a desktop yourself, and Replit's VNC pane is for a person. boat streams a 60fps desktop with computer-use APIs.
Drive the agents inside from outside
On Vercel the agents are installed but you write the code that prompts, steers and reads them. Replit's MCP server drives only Replit Agent, with no event stream. boat gives one API to prompt, steer and stream events.
Use boat when your agents work for hours on one machine: builds, tests, Docker, emulators and a desktop with a browser, with an API to drive the agents inside from outside. Compare it one to one: boat vs Vercel Sandbox and boat vs Replit.
Questions people ask
Is Vercel Sandbox cheaper than Replit?
Replit's bill is lower in four of our five scenarios, but it is not a like-for-like sandbox in any of them. One coding agent on workdays costs $57 on Vercel and $122 on Replit, while 50 parallel agents come to $2,884 on Vercel against $1,330 on Replit. boat costs $20 for the workday agent and $317 for the 50 agents.
Which is faster, Vercel Sandbox or Replit?
We cannot say, because Replit is not in the StarSling benchmark. Vercel Sandbox did 12.96 Node.js build-and-test runs per second at 4 vCPU / 8 GB, and boat did 26.69 on the same test.
Can Vercel Sandbox or Replit run Docker?
Vercel Sandbox can run Docker inside, with sudo. Replit sets up environments with Nix packages and its docs do not describe running Docker. Every boat sandbox has Docker, root, systemd and /dev/kvm.
Can either run an agent 24/7?
Not as one Vercel session: Pro sessions stop after 24 hours, and the resumed sandbox starts its processes over. A Replit Reserved VM runs continuously, but it is a published app billed at a fixed monthly price. boat machines have no session cap on paid plans.
Is Replit a sandbox for AI agents like Vercel Sandbox?
Not in the usual sense. Replit is an app builder where Replit Agent writes and publishes apps, and there is no API to start many machines. Vercel Sandbox and boat are both built for code that creates machines by API.
Where do they run?
Vercel Sandbox runs in 19 regions, with iad1 in the US as the default. Replit hosts data mainly in the US and publishes apps on five continents on Core and up. boat runs only in the EU, in Germany, Finland and France.
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