Runtime

Runloop alternatives: agent sandboxes ranked by cost

Runtime is the cheapest Runloop alternative, 88% less per job, and a paused sandbox keeps its memory and processes.

Runtime runs Runloop's devbox workload for 88% less, with memory that survives a pause. 1,000 one-minute runs of a 2 vCPU, 4 GiB sandbox cost $0.64 on Runtime and $5.33 on a Runloop MEDIUM devbox, $469 a month saved at 100,000 runs, with no $250 plan. Rates checked 23 September 2026.

Estimated compute cost

88% less than Runloop77% less than Daytona84% less than Modal

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

1,000

Compute only, at list rates checked 23 September 2026 (Runloop pricing, Daytona pricing, Modal pricing). Plan fees, network, taxes and free credits are left out. The worked example below shows the arithmetic.

Why do teams look beyond Runloop?

Runloop's devboxes are aimed at agent development and benchmarks. Runloop is the most expensive provider in the published rate comparison for this job, and the reasons to move follow from its meters and lifecycle:

  • Every meter is higher. $0.108 per CPU-hour against Runtime's $0.025, and $0.0252 per GB-hour of memory against $0.0075 per GiB-hour, plus disk at $0.00034236 per GB-hour while a devbox runs.
  • CPUs are billed while held. A devbox's CPUs count for as long as it runs, so an agent waiting on a model pays for them. Runtime measures CPU.
  • Suspend keeps only the disk. A suspended devbox keeps its disk, and its processes must be restarted. A paused Runtime sandbox wakes with its processes still running, kept for 1 to 365 days.
  • The plan. Pro is $250 a month plus usage. Runtime has no plan fee: prepaid credit from $10, with 50 free sandbox hours to start.

Which alternatives are cheapest?

The whole table uses one job at list rates: 1,000 runs, 60 seconds each, on a 2 vCPU, 4 GiB sandbox that works for 20 CPU-seconds per run. On Runloop that is a MEDIUM devbox with 2 CPUs, 4 GB and 8 GB of disk, and it comes last. Row-by-row sums are on pricing, excluding plan fees, storage, network, credits and negotiated rates.

# Provider Isolation CPU billed on 1,000 runs
1 Runtime Firecracker microVM, own kernel Measured CPU, with a small floor $0.64
2 Northflank microVMs for CPU work, gVisor for GPU work Allocated vCPUs $1.11
3 Cloudflare Sandbox (2 vCPU, 6 GiB, 12 GB disk) A container in its own VM Active CPU $1.35
4 Fly Machines, performance-2x with 4 GB Firecracker microVM The machine's size while started $1.44
5 Morph, 2 MCUs Full virtual machines The machine's size in MCUs $1.67
6 Vercel Sandbox, iad1 (4 GB) Firecracker microVM, own kernel Active CPU $2.12
7 CodeSandbox SDK, a Nano VM Firecracker microVM The VM's size, by the minute rounded up $2.48
8 E2B Firecracker microVM, own kernel Allocated vCPUs $2.76
9 Daytona Containers by default; VM class separate Allocated vCPUs $2.76
10 Blaxel (4 GB) Lightweight virtual machines Included with memory, active time $2.76
11 Fly Sprites (4 GB in use) Firecracker microVM Measured CPU $3.31
12 Modal Sandboxes (1 physical core) gVisor, a user-space kernel Requested or used, whichever is higher $3.97
13 Runloop, a MEDIUM devbox (the one you are replacing) microVM, with a container inside Allocated CPUs while running $5.33

Cost for the same job

The working for Runtime, Runloop and two rivals that also bill CPU for the whole run, one on allocation and one on request:

TextRuntime  CPU    1,000 × 20 s / 3,600 × $0.025           = $0.14         Memory 1,000 × 60 s / 3,600 × 4 × $0.0075      = $0.50         Total                                             $0.64Runloop  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                                             $5.33Daytona  CPU    1,000 × 60 s / 3,600 × 2 × $0.0504      = $1.68         Memory 1,000 × 60 s / 3,600 × 4 × $0.0162      = $1.08         Total                                             $2.76Modal    CPU    1,000 × 60 s × 1 core × $0.00003942     = $2.37         Memory 1,000 × 60 s × 4 × $0.00000667          = $1.60         Total                                             $3.97

Runloop already bills its CPUs as if they were always working, so busy for the whole minute on both CPUs the job is $1.33 on Runtime, $5.33 on Runloop, $2.76 on Daytona and $3.97 on Modal. Runloop's CPU line alone, $3.60, is more than Runtime's whole busy job. A month of 100,000 waiting runs comes to $63.89 on Runtime and $532.56 on Runloop.

What each alternative offers a Runloop user

1. Runtime: forks for parallel attempts

A Firecracker microVM with its own kernel per sandbox, at $0.025 per vCPU-hour of measured CPU, floored at a twentieth of a vCPU, and $0.0075 per reserved GiB-hour. Prepare an environment once and fork it into 1 to 10 running copies, memory and processes included, so every attempt at a task starts from the same point.

2. Northflank: in your own cloud, for less

The lowest allocated rates here, $0.01667 per vCPU-hour and $0.00833 per GB-hour. Like Runloop it deploys into your AWS, GCP or Azure account, and each sandbox is a service with a deployment plan.

3. Cloudflare Sandbox: Workers-first

Active CPU at $0.072 per vCPU-hour and no less than 3 GiB per vCPU, invoked from a Worker on the Workers Paid plan. An idle sandbox sleeps after 10 minutes and loses its files unless they went to R2.

4. Fly Machines: flat price per size

performance-2x with 4 GB costs $0.0861 an hour in iad, whatever the load, in 18 regions.

5. Morph: many branches of one machine

$0.05 per MCU-hour, one MCU being 1 vCPU, 4 GB of memory or 16 GB of disk. Infinibranch makes hundreds of replicas of a running machine with its memory, which suits search over many attempts.

6. Vercel Sandbox: wide concurrency

Firecracker at $0.128 per active CPU-hour and $0.0212 per GB-hour in iad1, with up to 10,000 sandboxes at once on Pro.

7. CodeSandbox SDK: fixed sizes in credits

A Nano VM (2 cores, 4 GB) is $0.1486 an hour, minute by minute and rounded up. Beyond 10 VMs at once, the Scale plan is $170 a month.

8. E2B: half Runloop's price for this job

Allocated at $0.0504 per vCPU-hour and $0.0162 per GiB-hour, $2.76 here. Hobby caps sessions at an hour and Pro, at $150 a month, at 24; the runtime is Apache-2.0.

9. Daytona: GPUs for model work

E2B's rates, containers by default with VMs as a separate class, GPU sandboxes, Windows machines and $200 of free compute.

10. Blaxel: standby that holds processes

$0.0000115 per GB-second of active time with CPU included. Standby keeps files and processes, and wakes in about 25 ms.

11. Fly Sprites: self-pausing sandboxes

$0.07 per measured CPU-hour and $0.04375 per GB-hour of memory in use; the 100 GB disk is always kept.

12. Modal Sandboxes: GPUs and functions

gVisor at $0.1419 per physical core-hour on the higher of request and use, alongside Modal's functions and scheduled jobs.

How to switch from Runloop

A devbox created per task becomes a sandbox created per task:

TypeScriptimport { Sandbox } from "withruntime";const box = await Sandbox.create({ funding: "trial" });try {  console.log((await box.exec("python3 -c 'print(6 * 7)'", { check: true })).stdout);} finally {  await box.stop();}

For benchmark runs, set the environment up once and fork it, so every attempt starts from the same running machine:

Pythonfrom withruntime import Sandboxwith Sandbox.create() as base:    base.exec("pip install --quiet requests")    forks = base.fork(count=2, funding="trial")  # copies as it is now, running    for fork in forks:        fork.stop()

You can also give a coding agent the single instruction in migration: it converts the project on a branch, checks it on the free trial and tells you the monthly saving. With a few runs behind you, npx withruntime compare --from runloop prices those same sandboxes at Runloop's published rates. For evaluation work, see agent evals and SWE-bench and RL environments.

Sources

Rival rates were checked 23 September 2026, with Runloop's pricing page read again on 25 September 2026.

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