Which is better, CodeSandbox or Prime Sandboxes?
It depends on machine size and workload. For agents that mostly wait on a model, Runtime has the lowest bill, $0.64 on the benchmark against $2.48 on CodeSandbox and $1.52 on Prime, with snapshots and forks that keep memory. Pick the CodeSandbox SDK for VMs above 16 cores, up to 64; pick Prime Sandboxes for RL training at scale, with 1,024 sandboxes to start.
At a glance
| CodeSandbox SDK | Prime Sandboxes | Runtime | |
|---|---|---|---|
| Isolation | Firecracker microVM | Hardware-virtualized microVM, own guest kernel | Firecracker microVM, own kernel |
| Price | Nano (2 cores, 4 GB) $0.1486 an hour in credits | $0.091 an hour for 2 vCPUs, 4 GiB, 5 GiB disk | Measured CPU and reserved memory |
| Largest | 64 cores and 128 GB | 16 vCPUs, 64 GiB, 128 GiB of disk | 16 vCPUs and 64 GiB, paid |
| Snapshots | Memory snapshot and restore | Filesystem checkpoints and forks; no memory | Pause and forks keep memory and processes |
| At once | 10 free; 250 on Scale at $170 a month | 1,024 to start | 100; more on request |
Snapshots today
CodeSandbox can snapshot a VM's memory and restore it. Prime's checkpoints save the filesystem only, and processes start fresh. On price and scale, Prime charges $0.091 an hour for this shape against CodeSandbox's $0.1486, and allows a thousand sandboxes without a plan. Runtime has memory snapshots, forks and the lowest price here.
Cost for the same job
2 cores and 4 GB, 60 seconds, 20 CPU-seconds, 1,000 runs; Prime with its 5 GiB default disk:
- Size
- 1,000 × 60 s / 3,600 × $0.1486
- $2.48
- 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
- CPU
- 1,000 × 20 s / 3,600 × $0.025
- $0.14
- Memory
- 1,000 × 60 s / 3,600 × 4 × $0.0075
- $0.50
Neither rival reads CPU use, so with both CPUs busy for the whole minute it is $2.48 on CodeSandbox and $1.52 on Prime, and $1.33 on Runtime.
Which one to pick
- CodeSandbox SDK for VMs above 16 cores, up to 64.
- Prime Sandboxes for RL training at scale.
- Runtime for the lowest bill, with snapshots and forks that keep memory.
See Runtime vs CodeSandbox and Runtime vs Prime Sandboxes.
Runtime Cloud
Runtime costs 74% less than CodeSandbox and 58% less than Prime. 1,000 runs of a minute on 2 vCPU and 4 GiB, each with 20 CPU-seconds of work, cost $2.48 on a CodeSandbox Nano VM, $1.52 on Prime Sandboxes and $0.64 on Runtime.
A free account is one command away: npx withruntime login. The migration guide covers moving code from another sandbox.
Sources
CodeSandbox rates checked 25 October 2026; Prime Sandboxes rates checked 25 October 2026.
- Together: CodeSandbox SDK, CodeSandbox SDK pricing
- Prime Sandboxes overview, Prime Sandboxes launch
- Runtime pricing
Facts on this page were checked on 26 October 2026.