Vercel Sandbox vs Blaxel: pricing, standby and limits

Vercel bills active CPU plus provisioned memory; Blaxel bills memory per active second with CPU included, and idles to standby for free.

Runtime runs the same job for 70% less than Vercel and 77% less than Blaxel. 1,000 one-minute runs of a 2 vCPU, 4 GiB sandbox cost $2.12 on Vercel, $2.76 on Blaxel and $0.64 on Runtime. Runtime bills measured CPU and reserved memory as two meters, both below either rival's rate, so it stays cheapest whether the code waits or works. Rates checked 23 September 2026.

At a glance

Vercel's figures are at the rates of its default iad1 region.

	Vercel Sandbox	Blaxel	Runtime
Isolation	Firecracker microVM, own kernel	Lightweight virtual machines	Firecracker microVM, own kernel
CPU	$0.128 per active CPU-hour	Included with memory; 8 GB gets 4 cores	$0.025 per vCPU-hour of measured CPU, with a small floor
Memory	$0.0212 per provisioned GB-hour; 2 GB per vCPU	$0.0000115 per GB-second of active time, $0.0414 an hour	$0.0075 per reserved GiB-hour
Plan fee	Hobby allowance free; usage beyond it needs Pro	None; tiers grow with credit added	None; prepaid credit from $10
Free start	5 active CPU-hours and 420 GB-hours a month on Hobby	Up to $200 of credit	50 sandbox hours, no card
When idle	Runs until its timeout or stop()	Standby about 15 seconds after the last connection closes	Pauses after the idle time you set; wakes on the next request
Kept while idle	The filesystem; processes start again	Files and processes, in a $0.20 per GB-month snapshot	Files, memory and processes, $0.08 per GB-month
Concurrency	10 on Hobby, 10,000 on Pro	Over 100,000 on the top tier	8 on the trial, 100 paid to start, raised on request

When is Blaxel cheaper than Vercel?

When the code is busy. Blaxel's price depends only on memory and time: CPU comes with the memory, so a 4 GB sandbox costs $0.1656 an hour whether its cores are idle or flat out. Vercel bills memory at about half Blaxel's rate, $0.0848 an hour for 4 GB, and then adds $0.128 for every CPU-hour the code actually uses.

So Vercel wins for agents that wait and Blaxel wins for agents that compute. For a 2 vCPU, 4 GB sandbox running a minute, the line falls at about 38 CPU-seconds of the 120 available: below that Vercel is cheaper, above it Blaxel is. With both CPUs busy the whole minute, Vercel costs about twice as much.

Blaxel's other difference is sizing. It sets CPU from memory, 4 cores for 8 GB, so a CPU-heavy job cannot take more cores without paying for more memory. Vercel gives 2 GB per vCPU. Runtime sizes vCPUs and memory apart.

What does idle time cost?

Blaxel's standby is its strongest feature. A sandbox goes to standby by itself about 15 seconds after its last connection closes, pays nothing for compute there, and resumes in about 25 ms, as Blaxel states it. The standby snapshot costs $0.20 per GB a month. A Vercel sandbox keeps billing until its timeout or stop(), and a stopped one starts its processes again.

Runtime pauses a sandbox after the idle time you set, keeps its memory and processes at $0.08 per GB a month, and wakes it on the next request, usually in about half a second:

TypeScriptimport { Sandbox } from "withruntime";const sbx = await Sandbox.create({ funding: "trial", idlePauseSeconds: 60 });await sbx.files.write("/workspace/task.txt", "step 1 done\n");// A minute with no requests pauses it. This read wakes it first:console.log(await sbx.files.readText("/workspace/task.txt"));await sbx.stop();

Cost for the same job

1,000 runs of a 2 vCPU sandbox with 4 GiB, or 4 GB on Vercel and Blaxel. Each run lasts 60 seconds and keeps the CPU busy for 20 CPU-seconds: an agent that mostly waits for a model.

TextVercel   CPU    1,000 × 20 s / 3,600 × $0.128      = $0.71         Memory 1,000 × 60 s / 3,600 × 4 × $0.0212 = $1.41         Total                                        $2.12Blaxel   Memory 1,000 × 60 s × 4 × $0.0000115      = $2.76Runtime  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

At 100,000 runs a month that is $212.44 on Vercel, $276.00 on Blaxel and $63.89 on Runtime. With both CPUs busy for the whole minute, it is $1.33 on Runtime against $5.68 on Vercel and $2.76 on Blaxel, so Runtime is cheaper however busy the sandbox is. The Blaxel figure assumes each sandbox goes to standby the moment its run ends. Plan fees, creations, snapshot storage, network and free credit are left out.

Which one to pick

• Pick Vercel Sandbox if your app is on Vercel, or you need a sandbox in a region you choose, from 19.
• Pick Blaxel for very large fleets, over 100,000 sandboxes at once on its top tier, or sandboxes that sit idle for free and resume in milliseconds.
• Pick Runtime for the lowest bill at any level of use, CPU and memory sized apart, and paused sandboxes kept with their memory at $0.08 per GB a month for 1 to 365 days.

Switch from either one

From Vercel Sandbox, one import changes and the code stays, with no Vercel project or token:

TypeScriptimport { Sandbox } from "withruntime/vercel"; // was: from "@vercel/sandbox"

Pythonfrom withruntime.vercel import sandbox  # was: from vercel import sandbox

From Blaxel, map its create, command, file and teardown calls with the table in migration. Standby needs no code: a request to a paused Runtime sandbox wakes it by default, and idlePauseSeconds sets when it pauses.

Or give your coding agent the one instruction in migration: it switches the project on a branch, tests it on the free trial and reports the monthly saving. From Vercel, npx withruntime switch --from vercel before your first top-up matches that top-up with credit, up to $100. The full side-by-sides are Runtime vs Vercel Sandbox and Runtime vs Blaxel.

Sources

Vercel Sandbox pricing rechecked 25 September 2026; the rest checked 23 September 2026.

• Vercel Sandbox pricing, Understanding Vercel Sandboxes
• Blaxel pricing, Blaxel sandboxes
• Runtime pricing

Facts on this page were checked on 25 September 2026.