# Cloudflare Sandbox vs Blaxel: pricing, idle costs and limits Cloudflare bills active CPU plus provisioned memory; Blaxel bills memory only, with CPU included, and goes to standby within seconds. **For an agent that waits on a model, Runtime costs 53% less than Cloudflare and 77% less than Blaxel.** The test job, 1,000 one-minute runs at 2 vCPU, is $1.35 on Cloudflare, $2.76 on Blaxel and $0.64 on Runtime. Cloudflare ties memory to vCPUs and Blaxel ties CPU to memory; Runtime prices the two apart, $0.025 per measured vCPU-hour and $0.0075 per GiB-hour, so neither drags the other up. Rates checked 23 September 2026. ## At a glance Cloudflare prices its Sandbox SDK as Cloudflare Containers, so those are the rates shown. | | Cloudflare Sandbox SDK | Blaxel | Runtime | | -------------- | -------------------------------------------------------- | ------------------------------------------ | -------------------------------------------------------- | | Isolation | A container in its own VM | Lightweight virtual machines | Firecracker microVM, own kernel | | CPU | $0.072 per active vCPU-hour, metered in 10 ms steps | Included with memory; 8 GB gets 4 cores | $0.025 per vCPU-hour of measured CPU, with a small floor | | Memory | $0.009 per provisioned GiB-hour; at least 3 GiB per vCPU | $0.0000115 per GB-second of active time | $0.0075 per reserved GiB-hour | | Idle | Sleeps after 10 idle minutes by default; files are lost | Standby about 15 s after connections close | Pause keeps files, memory and processes, 1 to 365 days | | Kept when idle | Nothing, unless backed up to R2 | Files and running processes, in a snapshot | Files, memory and running processes | | Idle storage | None kept | $0.20 per GB-month of snapshot | $0.08 per GB-month | | Plan fee | Workers Paid, at least $5 a month | None; tiers grow with credit added | None; prepaid credit from $10 | | Free start | No free tier; the plan includes 375 vCPU-minutes a month | Up to $200 of credit | 50 sandbox hours, no card | | Interfaces | A TypeScript SDK called from a Cloudflare Worker | TypeScript and Python SDKs | API, CLI, MCP server, JavaScript and Python SDKs | ## What does each one charge while the agent is idle? This is where the two differ most. A Blaxel sandbox goes to standby about 15 seconds after its last connection closes. In standby Blaxel charges nothing for memory, only for the snapshot's storage, and reconnecting resumes the sandbox in under 25 ms with its files and running processes. Blaxel's docs note that external connections, such as database connections or HTTP pools, are not kept. A Cloudflare sandbox that is not destroyed stays up, billing its provisioned memory and disk, until it has been idle for 10 minutes by default. Those ten minutes cost $9.50 per 1,000 sandboxes at the 2 vCPU, 6 GiB, 12 GB size below, several times the job itself. When it does sleep, its files and processes are gone. Set `sleepAfter` lower, or destroy each sandbox when its run ends. On Runtime, stop a sandbox when its run ends, or set `idlePauseSeconds` so it pauses by itself and wakes on the next request with memory and processes intact: ```ts check import { Sandbox } from "withruntime"; const sbx = await Sandbox.create({ idlePauseSeconds: 600 }); // ten idle minutes await sbx.update({ idlePauseSeconds: 1800 }); // change it later; 0 turns it off ``` ```python check from withruntime import Sandbox sbx = Sandbox.create(idle_pause_seconds=600) sbx.update(idle_pause_seconds=1800) # 0 turns it off sbx.stop() ``` ## Cost for the same job The sums below price 1,000 runs of 60 seconds on 2 vCPU, each with 20 CPU-seconds of real work. Blaxel gets 4 GB and Runtime 4 GiB. Cloudflare asks for at least 3 GiB per vCPU, so it is sized at 6 GiB, with the 12 GB of disk from Cloudflare's own example. ``` Cloudflare CPU 1,000 × 20 s × $0.000020 = $0.40 Memory 1,000 × 60 s × 6 × $0.0000025 = $0.90 Disk 1,000 × 60 s × 12 × $0.00000007 = $0.05 Total $1.35 Blaxel Memory 1,000 × 60 s × 4 × $0.0000115 = $2.76 Runtime CPU 1,000 × 20 s / 3,600 × $0.025 = $0.14 Memory 1,000 × 60 s / 3,600 × 4 × $0.0075 = $0.50 Total $0.64 ``` Across 100,000 runs in a month the bills are $135.04 on Cloudflare, $276.00 on Blaxel and $63.89 on Runtime. When both CPUs are busy for the whole minute, the job is $1.33 on Runtime, $3.35 on Cloudflare and $2.76 on Blaxel. Between the two rivals, Cloudflare stays cheaper until a run uses about 90 of its 120 CPU-seconds: its CPU is metered, while Blaxel's is bundled into a flat memory rate. The Cloudflare total assumes each sandbox is destroyed at the end of its run. The Blaxel total assumes standby starts the instant a run ends; in practice it starts about 15 seconds later, which adds $0.69 per 1,000 runs. Not counted: plan fees, Workers requests, Durable Object time, storage, network and free credit. ## Which one to pick | If what matters most is | Choose | | ----------------------------------------------- | ------------------ | | Sandboxes inside a Workers app, near users | Cloudflare Sandbox | | Free idle time and a resume in about 25 ms | Blaxel | | Over 100,000 sandboxes at once, on its top tier | Blaxel | | The lowest bill of the three at any load | Runtime | Runtime also keeps a paused sandbox's memory for $0.08 per GB-month, and its API works from any backend rather than from inside a Worker. ## Porting from each Cloudflare code maps call for call: `getSandbox(env.Sandbox, name)` to `Sandbox.getOrCreate(name)`, `sandbox.exec(cmd)` to `exec`, `proxyToSandbox` to `box.previews.create(port)`. Blaxel's standby has a direct counterpart in Runtime's automatic wake, which is on by default, so a request to a paused sandbox brings it back. Blaxel's create, run, file and delete calls become `Sandbox.create()`, `exec`, `files.write` and `files.read`, and `stop()`. The [migration](/docs/migrate) guide gives one instruction for a coding agent that ports the project on a branch and checks it on the free trial. Coming from Cloudflare, `npx withruntime switch --from cloudflare` before the first top-up matches it with credit, up to $100. Longer reads: [Runtime vs Cloudflare](/docs/cloudflare-sandbox-alternative), [Runtime vs Blaxel](/docs/blaxel-alternative) and [how to pause and resume a sandbox](/how-to/pause-and-resume-a-sandbox). ## Sources Rates checked 23 September 2026; Blaxel's sandbox overview and Cloudflare's sandbox lifecycle page read 25 September 2026. - [Cloudflare Containers pricing](https://developers.cloudflare.com/containers/pricing/), [Containers limits and instance types](https://developers.cloudflare.com/containers/platform/limits/), [Sandbox lifecycle](https://developers.cloudflare.com/sandbox/concepts/sandboxes/) - [Blaxel pricing](https://blaxel.ai/pricing), [Blaxel sandboxes](https://docs.blaxel.ai/Sandboxes/Overview) - Runtime [pricing](/docs/pricing) Facts on this page were checked on 25 September 2026.