Runtime

Blaxel alternatives: agent sandboxes ranked by cost

Runtime is the cheapest Blaxel alternative, 77% less per job, with CPU and memory priced on separate meters.

Runtime runs Blaxel's workload for 77% less, and prices CPU and memory separately. 1,000 one-minute runs of a 2 vCPU, 4 GiB sandbox cost $0.64 on Runtime and $2.76 on Blaxel, $212 a month saved at 100,000 runs. Runtime stays cheaper when the CPU is busy too, and keeps paused work for $0.08 per GB a month against Blaxel's $0.20. Rates checked 23 September 2026.

Estimated compute cost

77% less than Blaxel81% less than Fly Sprites77% less than E2B

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

1,000

Compute only, at list rates checked 23 September 2026 (Blaxel pricing, Fly.io pricing, E2B pricing). Plan fees, network, taxes and free credits are left out. The worked example below shows the arithmetic.

Why do teams look beyond Blaxel?

Blaxel sells one meter, memory for the time a sandbox is active, and the CPU comes with it. That is simple, and it is where the reasons to move come from:

  • The memory rate carries everything. $0.0000115 per GB-second is $0.0414 per GB-hour, more than five times Runtime's $0.0075 per GiB-hour. Runtime bills measured CPU on top, at $0.025 per vCPU-hour, and the total is still lower.
  • CPU is set by memory. 8 GB gets 4 cores. A job that needs more CPU buys memory it does not use; on Runtime you choose vCPUs and memory apart.
  • Paused work costs more to keep. Blaxel's standby snapshots cost $0.20 per GB a month. A paused Runtime sandbox keeps its files, memory and processes for $0.08 per GB a month, for 1 to 365 days.
  • Standby is not immediate. Blaxel's docs say standby starts about 15 seconds after the last connection closes.

Which alternatives are cheapest?

One job, priced at list rates everywhere: 1,000 runs of a 2 vCPU, 4 GiB sandbox lasting 60 seconds, of which 20 CPU-seconds are real work. Blaxel is priced at 4 GB of memory while active, which ties it with E2B and Daytona. The sums for every row are on pricing; they leave out 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) (the one you are replacing) 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 microVM, with a container inside Allocated CPUs while running $5.33

Cost for the same job

The working for Runtime, Blaxel, Fly Sprites (the other sandbox that pauses itself) and E2B:

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                                          $0.64Blaxel   Memory 1,000 × 60 s × 4 × $0.0000115        = $2.76Sprites  CPU    1,000 × 20 s / 3,600 × $0.07         = $0.39         Memory 1,000 × 60 s / 3,600 × 4 × $0.04375  = $2.92         Total                                          $3.31E2B      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                                          $2.76

Because Blaxel's single meter ignores CPU, keeping both CPUs busy for the whole minute leaves it where it was: the job reads $1.33 on Runtime, $2.76 on Blaxel, $5.25 on Sprites and $2.76 on E2B, and Runtime's busy figure is still under half of Blaxel's. Over a month of 100,000 waiting runs, that is $63.89 on Runtime against $276.00 on Blaxel.

The Blaxel figure assumes each sandbox goes to standby the moment its run ends.

How each alternative compares for a Blaxel user

1. Runtime: two meters, cheaper pauses

Memory costs $0.0075 per reserved GiB-hour, about a fifth of Blaxel's $0.0414 per GB-hour, and CPU is metered separately on use at $0.025 per vCPU-hour, with a floor of a twentieth of a vCPU. idlePauseSeconds gives the same hands-off standby: a quiet sandbox pauses, and the next request wakes it with its processes. Read-only keys, a daily spending limit per key and maxCostMicros keep an agent's spending bounded.

2. Northflank: low allocated rates, CPU chosen apart

$0.01667 per vCPU-hour and $0.00833 per GB-hour, so a job that needs more CPU than memory does not have to buy the memory. Each sandbox is a service with a deployment plan, and it can deploy into your AWS, GCP or Azure account.

3. Cloudflare Sandbox: sleep that forgets

Active CPU at $0.072 per vCPU-hour, 3 GiB per vCPU at least, and a Worker on the Workers Paid plan to call it. It sleeps after 10 idle minutes, but where a Blaxel standby keeps state, a Cloudflare sandbox restarts from its image with its files gone unless R2 has a copy.

4. Fly Machines: flat hourly sizes

performance-2x with 4 GB costs $0.0861 an hour in iad, in 18 regions. Its root disk is temporary, and suspend is the way to keep memory.

5. Morph: copy a machine mid-run

At $0.05 per MCU-hour, where an MCU is 1 vCPU, 4 GB of memory or 16 GB of disk, Morph is billed by the largest need. Infinibranch turns one running machine, memory and all, into hundreds of copies.

6. Vercel Sandbox: active CPU, filesystem stops

A Firecracker microVM at $0.128 per active CPU-hour and $0.0212 per GB-hour in iad1. Stopping keeps the filesystem, and processes start fresh.

7. CodeSandbox SDK: memory snapshots in fixed shapes

The Nano VM (2 cores, 4 GB) is $0.1486 an hour, billed by the minute rounded up, and supports memory snapshot and restore. Its free Build plan allows 10 VMs at once.

8. E2B: separate meters, billed on allocation

$0.0504 per vCPU-hour and $0.0162 per GiB-hour. Hobby sandboxes stop after one hour; Pro, at $150 a month, runs them for 24.

9. Daytona: E2B's price with GPUs

Identical rates to E2B, a container unless you choose the VM class, GPU sandboxes, Windows machines and $200 of free compute.

10. Fly Sprites: the other sandbox that sleeps itself

$0.07 per measured CPU-hour and $0.04375 per GB-hour of memory in use. When a Sprite sleeps, its 100 GB disk costs $0.02 per GB a month.

11. Modal Sandboxes: gVisor and GPUs

$0.1419 per physical core-hour on the larger of request and use, beside Modal's GPU functions.

12. Runloop: benchmark devboxes

$0.108 per CPU-hour, $0.0252 per GB-hour and a disk charge, with SWE-Bench and other public benchmarks.

How to switch from Blaxel

The call to run code is short on Runtime, in TypeScript or Python:

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();}
Pythonfrom withruntime import Sandboxwith Sandbox.create(funding="trial") as box:    print(box.exec("python3 -c 'print(6 * 7)'", check=True).stdout)

Blaxel's standby maps to a named sandbox that pauses when idle. It wakes on the next exec, file call or preview visit, usually in about half a second, with its memory and processes:

TypeScriptimport { Sandbox } from "withruntime";const dev = await Sandbox.getOrCreate("dev", { idlePauseSeconds: 900 });await dev.exec("git pull || true");

A coding agent can handle the rest: paste the instruction from migration, and it swaps the calls on a branch, runs them on the free trial and totals the monthly saving. Once some real sandboxes have run, npx withruntime compare --from blaxel prices them at Blaxel's published rates. More on pausing: pause and resume a sandbox and sandbox snapshot.

Sources

The rival rates were checked 23 September 2026; Blaxel's pricing page was read once more on 25 September 2026.

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