Sandbox guide

Money

Billing models

The meter decides your bill more than the hourly rate does. Four shapes are in play: flat per size, per vCPU and per GB, a plan fee that returns as credit, and measured CPU.

12 providersEvery claim dated 2026-10-28Sources linked

The idea

Flat per size: you pick a fixed shape and pay an hourly rate for it whether it works or waits. Boat, Sandboxer and Lizard work this way. It is the easiest to predict and the easiest to compare.

Per vCPU and per GB: the rate is a sum of parts, so much per vCPU-hour, per GB-hour of memory and per GB-month of disk. Agent 37, InstaBox, E2B and Vercel work this way, and boxd uses three meters of its own. It is flexible and hard to compare, because two providers can quote the same hourly number for different amounts of memory.

A plan fee that returns as credit: Sandboxer, InstaBox, Lizard and Boat sell a monthly plan whose dollars convert into usage. That is not a fee, but it is a floor: a light month still costs the plan price, and unused plan time usually expires. Morph's MCU model is a fourth shape: the rate is the largest resource dimension, not the sum.

Where providers split

The claim on the left, the provider's own words on the right

Reserved size versus measured use

A flat rate bills the shape you reserved. A measured meter bills what the machine used, which can be much less or much more than the shape suggests. Runtime bills measured active CPU with a 50-millicore floor plus reserved memory. Sprites bills actual CPU and actual memory. Vercel bills active CPU excluding I/O wait, plus provisioned memory.

The difference is largest for an agent waiting on a model. Runtime's floor makes an idle-but-running box cost about $0.03 an hour; a flat 2 vCPU / 4 GiB shape costs its full hourly rate whether it waits or not.

The plan is a floor, not a fee

Boat's $20 plan buys $20 of VM time, and unused time expires monthly. Sandboxer's $20 buys about 555 default-hours, and the plan converts into machine time. InstaBox and Lizard treat the fee as a monthly credit that resets.

The trap is a workload that costs $3 of usage and still bills $20. That is not a pricing error; it is the floor doing its job.

What is still charged while stopped

Agent 37, InstaBox and Runtime charge storage. Sandboxer counts stopped storage against a free quota. Boat charges nothing and keeps the disk for 14 days. boxd charges for written disk in every state and for memory in standby. Lizard's stop deletes the sandbox. E2B does not bill paused or killed sandboxes, but volumes and snapshots are separate.

Vercel is the one to read carefully: persistent sandboxes save a snapshot on stop, and snapshot storage bills separately from compute.

What to watch for

The details that decide the answer in practice

  1. 01

    Whether the meter measures reserved size, actual CPU, or resident memory.

  2. 02

    Whether the monthly fee returns as usage, and what expires at month end.

  3. 03

    What is charged while stopped: compute, memory, storage, or nothing.

  4. 04

    Which costs are absent from the pricing page: egress, snapshots, static IPs.

  5. 05

    Whether there is a minimum billed duration or a one-minute increment.

Compare all twelve

Docs read 28 October 2026

The meter decides your bill more than the hourly rate does. Four shapes are in play: flat per size, per vCPU and per GB, a plan fee that returns as credit, and measured CPU.
ProviderDoes it?What that means
Agent 37YesPrepaid wallet, per minute, priced from the reserved shape: $0.80 per vCPU-month, $0.70 per GB-month, $0.09 per GB-month of disk. No plan fee, no minimum, stopped time is disk only.
“You top up a prepaid balance and each sandbox spends it down per minute while it runs. No subscription, no plan fee, no minimum”
Agent 37pricing-page
BlaxelPartlyActive compute is billed on allocated RAM per second at $0.0000115 per GB-second, with CPU included. Snapshots and volumes bill separately; tiers are wallet top-ups, not subscriptions.
“$0.0000115 / GB RAM · second”
Blaxelpricing-page
BoatPartlyA monthly plan that is prepaid machine time plus limits, with a separate dollar wallet for overage. Per second while running; stopped is zero machine time and the disk is kept 14 days.
“A plan is a monthly price that your card pays. It is not a fee. Every dollar comes back as VM time at the rates above.”
Boatpricing-page
boxdPartlyPrepaid credits and three meters: vCPU on the size while running, RAM on resident memory (also in standby), disk on bytes written in every state. No plan fee; storage prices are unpublished.
“RAM bills on the memory a machine actually has resident, sampled every second, while it is running or in standby”
boxdpricing-page
E2BPartlyPer second of allocated vCPU and RAM while running, against a credit balance. Paused and killed sandboxes are not billed. Pro adds a $150 monthly fee; Hobby has a one-time $100 credit.
“We charge per second of a running sandbox.”
E2Bpricing-page
InstaBoxYesA subscription that is also credit: $20, $100 or $500 a month, then per-second vCPU and RAM, GiB-hour storage and $0.02 per GiB of egress. Paused and stopped machines pay storage only.
“Usage comes out of your included credits first, then you pay as you go. Credits reset every month.”
InstaBoxpricing-page
LizardPartlyOne $19 plan including $19 of usage; sandboxes are a flat hourly price per size, billed per second including idle, and volumes bill on used space. Snapshot storage has no published price.
“Pro costs $19 a month and includes $19 of usage for the whole platform: apps, databases, Sandboxes, storage and egress.”
Lizardpricing-page
MorphPartlyMCUs where the rate is the largest resource dimension: 1 vCPU-hour, 4 GB RAM-hours, 16 GB disk-hours or 5 TB snapshot-hours, at $0.05 per MCU-hour. Plans include MCU allocations.
“MCUs = max(vCPUs, ceil(RAM/4GiB), ceil(disk/16GiB))”
Morphpricing-page
RuntimePartlyPrepaid credit, per second: measured active CPU above a 50-millicore floor, plus reserved memory, plus storage while paused or stopped. No plan fee; plans are in a private beta.
“Compute has no one-minute minimum, and memory is billed while compute runs.”
Runtimepricing-page
SandboxerPartlyA monthly plan whose dollars return as machine time, metered per second at a fixed multiplier per size. Stopped time is free, but the $20 plan is a floor and plan time expires monthly.
“Metering is per second, from the moment a sandbox is up until it is stopped.”
Sandboxerdocs-confirmed
SpritesPartlyActual CPU at $0.0385 per CPU-hour and actual memory at $0.021875 per GB-hour, plus hot and cold storage. The pricing page says there are no plans; the product FAQ describes plans.
“Cumulative CPU usage measured by cpu.stat”
Spritespricing-page
Vercel SandboxPartlyActive CPU at $0.128 per CPU-hour excluding I/O wait, provisioned memory at $0.0212 per GB-hour with a one-minute minimum, plus creations, transfer, snapshots and drives.
“Time spent waiting for I/O (such as network requests, database queries, or AI model calls) does not count toward Active CPU.”
Vercel Sandboxpricing-page

Part of Money. Next: put two or three providers side by side.