Vercel Sandbox vs Fly Sprites pricing, memory and idle time

Which is better, Vercel Sandbox or Fly Sprites?

It depends on how long your agents live between tasks. For agents that mostly wait on a model, Runtime costs $0.64 for the job below, against $2.40 on Sprites and $2.12 on Vercel. Runtime also sizes memory to the job and keeps it through a pause. Pick Vercel Sandbox for an app on Vercel, a region you choose from 19, or up to 10,000 sandboxes on Pro. Pick Sprites for agent computers that sleep at $0.02 per GB-month, or for SDKs in Go and Elixir.

At a glance

Vercel's figures are at the rates of its default iad1 region.

Which is cheaper, Vercel Sandbox or Sprites?

Vercel, for the one-minute job below: $2.12 against $2.40 on Sprites. A Sprite stays awake, and billed, for about 30 seconds after each run. Memory costs about the same on both. Sprites charge $0.021875 per GB-hour of memory in use, about the same Vercel's $0.0212 per provisioned GB-hour. Sprites' CPU is cheaper, at $0.0385 an hour against $0.128, so busy code favours Sprites. With both CPUs busy the whole minute, the job costs $3.47 on Sprites and $5.68 on Vercel.

Two things move the Sprite figure down. It bills the memory it actually uses, so a job that uses 1 GB for the minute pays $0.76 for these runs instead of $2.40. And it pauses by itself, so a Sprite you forget costs little. The figures include the 30 seconds or so a Sprite stays awake, and billed, after each run.

What happens between tasks?

This decides the cost of an agent that works in bursts. A Sprite pauses itself when idle and keeps its disk. Its memory is kept at first, then dropped when it goes cold, at a time you do not choose. A Vercel sandbox runs until its timeout or a stop(), which keeps its filesystem. Processes start again next session.

A Runtime sandbox pauses after the idle time you set, keeps its memory and running processes while you have credit, and wakes on the next request:

Pythonfrom withruntime import Sandboxdev = Sandbox.get_or_create("agent-dev", idle_pause_seconds=300)dev.exec("git --version", check=True)# Five quiet minutes later it pauses; the next call wakes it where it stopped.print(Sandbox.get_or_create("agent-dev").exec("uptime").stdout)

See how to pause and resume a sandbox.

Cost for the same job

1,000 runs of a 2 vCPU sandbox with 4 GiB, or 4 GB on Vercel. The Sprite is assumed to use all 4 GB for the whole minute. Each run lasts 60 seconds and keeps the CPU busy for 20 CPU-seconds: an agent that mostly waits for a model.

At 100,000 runs a month, the cost is $212.44 on Vercel, $240.14 on Sprites and $63.89 on Runtime. With both CPUs busy for the whole minute, it is $1.33 on Runtime, against $5.68 on Vercel and $3.47 on Sprites. Runtime is cheaper however busy the sandbox is. Plan fees, creations, storage, network and free allowances are left out.

Which one to pick

• Pick Vercel Sandbox if your app is on Vercel, or you need sandboxes in a region you choose, from 19, with up to 10,000 running at the same time on Pro.
• Pick Sprites for long-lived agent computers that sleep cheaply. A sleeping Sprite's disk costs $0.02 per GB-month, with SDKs for Go and Elixir as well as JavaScript and Python.
• Pick Runtime for measured CPU at 80% below Vercel's rate and 35% below Sprites', memory sized to the job, and a pause that keeps memory for as long as you choose.

Switch from either one

From Vercel Sandbox, change the import and keep the code, with no Vercel project or token:

TypeScriptimport { Sandbox } from "withruntime/vercel"; // was: from "@vercel/sandbox"

From Sprites, client.createSprite(name) becomes Sandbox.getOrCreate(name) (or Sandbox.create() for a one-off). sprite.execFile(cmd, args) becomes exec([cmd, ...args]), and sprite.delete() becomes stop():

TypeScriptimport { Sandbox } from "withruntime";const box = await Sandbox.create();try {  await box.files.write("/workspace/invoice.py", "print(sum([125, 250, 375]))\n");  console.log((await box.exec(["python3", "/workspace/invoice.py"], { check: true })).stdout);} finally {  await box.stop();}

Or give your coding agent the one instruction in migration. It switches the project on a branch, tests it on the free usage and reports the monthly saving. Credit you add within 30 days of signing up is matched, up to $1,000 in total. The full side-by-sides are Runtime vs Vercel Sandbox and Runtime vs Fly.io.

Sources

Fly.io prices checked 25 October 2026.

Vercel Sandbox pricing rechecked 25 October 2026; the rest checked 25 October 2026.

• Vercel Sandbox pricing, Understanding Vercel Sandboxes
• Fly.io pricing, Sprites, Sprites documentation, Sprites lifecycle and persistence
• Runtime pricing

Facts on this page were checked on 26 October 2026.