Which is better, E2B or Prime Sandboxes?
It depends on scale and on how long paused sandboxes must last. For agents and rollouts that wait on a model, Runtime is the cheapest here: $0.64 for the job, against $1.52 on Prime and $2.76 on E2B, with pause and forks that keep memory. Pick Prime Sandboxes for thousands of concurrent rollouts inside Prime Intellect's training platform. Pick E2B when paused sandboxes must last with no expiry, or when you may self-host.
At a glance
| E2B | Prime Sandboxes | Runtime | |
|---|---|---|---|
| Isolation | Firecracker microVM, own kernel | Hardware-virtualized microVM, own guest kernel | Firecracker microVM, own kernel |
| CPU | $0.0504 per allocated vCPU-hour | $0.02 per vCPU-hour while running | $0.025 per vCPU-hour of measured CPU, with a small floor |
| Memory | $0.0162 per GiB-hour | $0.0125 per GiB-hour | $0.0075 per reserved GiB-hour |
| Largest | 8 vCPUs and 8 GiB | 16 vCPUs, 64 GiB, 128 GiB of disk | 16 vCPUs and 64 GiB, paid |
| At once | Set by plan | 1,024 per account to start | 100 paid |
| Pause and fork | Pause keeps memory | Filesystem checkpoints and forks; no memory | Pause keeps memory; forks of a running sandbox |
| Price terms | Hobby $0; Pro $150 per month | Published through 22 December 2026 | Fixed in each quote; no plan |
Rates against features
Prime is cheaper than E2B at every level of use here: its CPU rate is under half of E2B's, and its memory is about a quarter lower. What E2B has that Prime does not is memory state. An E2B pause keeps memory and processes with no expiry. Prime's checkpoints and forks save the filesystem only, and processes start fresh. Prime starts accounts at 1,024 concurrent sandboxes, built for reinforcement learning rollouts.
Cost for the same job
2 vCPU, 4 GiB, 60 seconds and 20 CPU-seconds a run, 1,000 runs, with Prime's default 5 GiB disk:
- CPU
- 1,000 × 60 s / 3,600 × 2 × $0.0504
- $1.68
- Memory
- 1,000 × 60 s / 3,600 × 4 × $0.0162
- $1.08
- 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
That is $276.00, $151.67 and $63.89 per month at 100,000 runs. With the CPUs busy for the whole minute, the job costs $2.76 on E2B, $1.52 on Prime and $1.33 on Runtime. Runtime stays cheapest because its memory is the cheapest.
Which one to pick
- E2B when paused sandboxes must last with no expiry, or you may self-host.
- Prime Sandboxes for thousands of concurrent rollouts from the first day, inside Prime Intellect's training platform.
- Runtime for agents and rollouts that wait on a model: the lowest bill, pause and forks that keep memory, and eval harnesses (Harbor, Inspect) that switch without code changes.
See Runtime vs E2B and Runtime vs Prime Sandboxes.
Runtime Cloud
Runtime costs 77% less than E2B and 58% less than Prime Sandboxes on the same job. 1,000 one-minute runs of a 2 vCPU, 4 GiB sandbox with 20 CPU-seconds of work each cost $2.76 on E2B, $1.52 on Prime and $0.64 on Runtime. Prime's rates are the lower of the two rivals' rates, and Runtime's measured CPU undercuts both.
Run a few rollouts on the free usage. Start with npx withruntime login. Code
written for E2B switches by import, as the migration guide describes.
Sources
E2B rates checked 25 October 2026; Prime rates checked 25 October 2026.
- E2B pricing, E2B sandbox persistence
- Prime Sandboxes overview, Prime Sandboxes launch
- Runtime pricing
Facts on this page were checked on 26 October 2026.