Cloudflare Sandbox vs Prime Sandboxes: pricing and fit

Cloudflare bills active CPU but needs 3 GiB per vCPU; Prime bills everything while running. The 2 vCPU benchmark is $1.35 on Cloudflare and $1.52 on Prime.

Runtime costs 53% less than Cloudflare and 58% less than Prime on it. 1,000 one-minute runs of a 2 vCPU, 4 GiB sandbox with 20 CPU-seconds of work each: $1.35 on Cloudflare Sandbox (priced at its 6 GiB minimum), $1.52 on Prime Sandboxes and $0.64 on Runtime.

Estimated compute cost

53% less than Cloudflare Sandbox58% less than Prime Sandboxes

2 vCPUs · 4 GiB · 60 s a run · 20 CPU-seconds busy

Runs1,000

Compute only, at list rates checked 23 September 2026 and 25 September 2026 (Cloudflare Containers pricing, Prime Sandboxes overview). Plan fees, network, taxes and free credits are left out. The worked example below shows the arithmetic.

At a glance

	Cloudflare Sandbox	Prime Sandboxes	Runtime
Isolation	A container in its own VM	Hardware-virtualized microVM, own guest kernel	Firecracker microVM, own kernel
CPU	$0.072 per active vCPU-hour	$0.02 per vCPU-hour while running	$0.025 per vCPU-hour of measured CPU, with a small floor
Memory	$0.009 per provisioned GiB-hour, 3 GiB per vCPU at least	$0.0125 per GiB-hour	$0.0075 per reserved GiB-hour
Largest	4 vCPUs, 12 GiB, 20 GB	16 vCPUs, 64 GiB, 128 GiB of disk	16 vCPUs and 64 GiB, paid
Idle	Sleeps after 10 idle minutes; files lost	Idle timeout off by default	Pause keeps memory, 1 to 365 days
Fleet	1,500 vCPUs per account	1,024 sandboxes, 4,096 vCPUs to start	100 sandboxes (50 the first week), 200 vCPUs

Edge against scale

Cloudflare places a sandbox near the user who asked for it and bills only the CPU that works, but forces memory up with CPU and forgets files on sleep. Prime runs large microVMs by the thousand at a flat low rate. Both suit short tasks; neither keeps a sandbox's memory between steps today.

Cost for the same job

The benchmark, 60 seconds a run (6 GiB and a 12 GB disk on Cloudflare, 5 GiB of disk on Prime):

TextCloudflare  CPU    1,000 × 20 s × $0.000020                     = $0.40            Memory 1,000 × 60 s × 6 × $0.0000025                = $0.90            Disk   1,000 × 60 s × 12 × $0.00000007              = $0.05            Total                                                  $1.35Prime       CPU    1,000 × 60 s / 3,600 × 2 × $0.02              = $0.67            Memory 1,000 × 60 s / 3,600 × 4 × $0.0125            = $0.83            Disk   1,000 × 60 s / 3,600 × 5 × $0.0002            = $0.02            Total                                                  $1.52Runtime     CPU    1,000 × 20 s / 3,600 × $0.025                = $0.14            Memory 1,000 × 60 s / 3,600 × 4 × $0.0075           = $0.50            Total                                                  $0.64

With both CPUs busy for the whole minute, the job costs $3.35 on Cloudflare, $1.52 on Prime and $1.33 on Runtime.

Which one to pick

Cloudflare Sandbox for Workers apps that want sandboxes at the edge.
Prime Sandboxes for large, parallel RL rollouts.
Runtime for the lowest cost and memory kept across pauses.

See Runtime vs Cloudflare Sandbox and Runtime vs Prime Sandboxes.

Sources

Cloudflare rates checked 23 September 2026; Prime Sandboxes rates checked 25 September 2026.

Facts on this page were checked on 25 September 2026.