Runloop vs Prime Sandboxes: sandboxes for evals and training
Runloop and Prime both court agent evaluation and training teams. Runloop is the dearest in the benchmark at $5.33; Prime costs $1.52.
Runtime runs the benchmark for 88% less than Runloop and 58% less than
Prime. 1,000 one-minute runs of a 2 vCPU, 4 GiB sandbox, 20 CPU-seconds of
work each: $5.33 on a Runloop MEDIUM devbox, $1.52 on Prime Sandboxes, $0.64
on Runtime.
Estimated compute cost
88% less than Runloop58% less than Prime Sandboxes
2 vCPUs · 4 GiB · 60 s a run · 20 CPU-seconds busy
Compute only, at list rates checked 23 September 2026 and 25 September 2026 (Runloop pricing, Prime Sandboxes overview). Plan fees, network, taxes and free credits are left out. The worked example below shows the arithmetic.
At a glance
| Runloop | Prime Sandboxes | Runtime | |
|---|---|---|---|
| Isolation | microVM, with a container inside | Hardware-virtualized microVM, own guest kernel | Firecracker microVM, own kernel |
| CPU | $0.108 per CPU-hour while running | $0.02 per vCPU-hour while running | $0.025 per vCPU-hour of measured CPU, with a small floor |
| Memory | $0.0252 per GB-hour | $0.0125 per GiB-hour | $0.0075 per reserved GiB-hour |
| Evals | SWE-Bench and custom benchmarks built in | Environments for Prime's RL training | Harbor and Inspect integrations |
| Plan | Basic free; Pro $250 a month plus usage | None; rates through 22 December 2026 | None; prepaid credit from $10 |
Tooling against price
Runloop sells the benchmark harness: public suites ready to run and custom ones built from your data, with compliance statements for enterprises. Prime sells the environment at a low price and huge parallelism. Runtime plugs into the harnesses teams already use, Harbor with Terminal-Bench and Inspect, and charges less per rollout than either.
Cost for the same job
The benchmark, 60 seconds a run (a MEDIUM devbox with 8 GB of disk; Prime
with 5 GiB):
TextRunloop CPU 1,000 × 60 s / 3,600 × 2 × $0.108 = $3.60 Memory 1,000 × 60 s / 3,600 × 4 × $0.0252 = $1.68 Disk 1,000 × 60 s / 3,600 × 8 × $0.00034236 = $0.05 Total $5.33Prime 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 $0.64With both CPUs busy for the whole minute, the job costs $5.33 on Runloop, $1.52 on Prime and $1.33 on Runtime.
Which one to pick
- Runloop for managed benchmark suites and compliance statements.
- Prime Sandboxes for RL rollouts by the thousand.
- Runtime for eval runs at the lowest price, through Harbor or Inspect.
See Runtime vs Runloop and Runtime vs Prime Sandboxes.
Sources
Runloop rates checked 23 September 2026; Prime Sandboxes rates checked 25 September 2026.
Facts on this page were checked on 25 September 2026.