Vercel Sandbox vs Northflank: sandbox pricing, isolation and limits

Vercel bills active CPU in Firecracker microVMs; Northflank bills allocated CPU in Kata or gVisor microVMs, at a much lower rate.

For an agent that mostly waits on a model, Runtime is 70% cheaper than Vercel and 42% cheaper than Northflank. One thousand one-minute runs of a 2 vCPU, 4 GiB sandbox bill $2.12 on Vercel, $1.11 on Northflank and $0.64 on Runtime. Runtime charges measured CPU, as Vercel does, at about a fifth of Vercel's rate, and its memory rate is the lowest of the three. Rates checked 23 September 2026.

At a glance

Vercel is priced at its default region, iad1.

	Vercel Sandbox	Northflank	Runtime
Isolation	Firecracker microVM, own kernel	A microVM per workload, with Kata Containers or gVisor	Firecracker microVM, own kernel
CPU	$0.128 per active CPU-hour	$0.01667 per allocated vCPU-hour	$0.025 per vCPU-hour of measured CPU, with a small floor
Memory	$0.0212 per provisioned GB-hour; 2 GB per vCPU	$0.00833 per GB-hour	$0.0075 per reserved GiB-hour
Plan fee	Hobby allowance free; usage beyond it needs Pro	None published for compute	None; prepaid credit from $10
Free start	5 active CPU-hours and 420 GB-hours a month on Hobby	2 free services and 1 free database	50 sandbox hours, no card
Session length	45 minutes on Hobby, 24 hours on Pro, per session	No forced time limit	Leases of up to an hour, extended as often as needed
Where it runs	19 Vercel regions	Northflank's regions, or your AWS, GCP, Azure or Oracle VPC	Dedicated servers Runtime operates
What you create	A sandbox, in a Vercel project	A service with a deployment plan	A sandbox, in one call

Why is Northflank cheaper even though Vercel bills only active CPU?

Because the rates are far apart. Vercel's active CPU costs $0.128 an hour; Northflank's allocated vCPU costs $0.01667, under a seventh as much. Vercel only bills the CPU the code uses, but even an agent busy a sixth of the time pays more on Vercel than for a whole allocated vCPU on Northflank. Memory is the same story: $0.0212 per GB-hour on Vercel against $0.00833 on Northflank, and both bill it for the whole run.

In the example below Northflank costs about half of Vercel for an agent that waits, and about a fifth when both CPUs are busy. Runtime's measured CPU at $0.025 a vCPU-hour puts it under both while the agent waits.

Which one lets a sandbox live longest?

A Vercel session runs for up to 24 hours on Pro and 45 minutes on Hobby. The limit applies to each session, so a persistent sandbox that stops and resumes lives on. Northflank states no forced time limit: a sandbox can run for seconds or weeks. It is created as a service, so it also brings a deployment plan.

A Runtime sandbox runs on a lease of up to an hour that you extend as often as needed, or, on a paid account, persistent=True keeps it running for as long as the account has credit, under a cost ceiling you set. Between tasks it can pause and keep its memory:

Pythonfrom withruntime import Sandboxworker = Sandbox.get_or_create("long-lived-worker", idle_pause_seconds=900)worker.files.write("/workspace/progress.txt", "step 3 of 10\n")print(worker.files.read_text("/workspace/progress.txt"))worker.extend(1800)  # more time before the lease ends

Cost for the same job

The worked case: 1,000 runs on 2 vCPU with 4 GiB (4 GB on both Vercel and Northflank), 60 seconds per run, 20 CPU-seconds of that spent computing.

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                                         $2.12Northflank  CPU    1,000 × 60 s / 3,600 × 2 × $0.01667 = $0.556            Memory 1,000 × 60 s / 3,600 × 4 × $0.00833 = $0.555            Total                                         $1.11Runtime     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, Vercel totals $212.44, Northflank $111.10 and Runtime $63.89. With both CPUs busy for the whole minute it is $1.33 on Runtime, $5.68 on Vercel and $1.11 on Northflank, which makes Northflank the cheapest of the three for work that saturates every CPU. Runtime stays under Northflank until a one-minute run keeps its CPUs busy for about 88 of 120 CPU-seconds. Plan fees, creation charges, storage, network and free allowances are excluded.

Which one to pick

Situation	Best fit
The app is on Vercel; up to 10,000 sandboxes on Pro	Vercel Sandbox
CPU-bound jobs that keep every core busy	Northflank
Sandboxes that run for weeks, or inside your own cloud	Northflank
Agents that wait on a model	Runtime

In that last case, measured CPU puts Runtime 42% below Northflank and 70% below Vercel, and pause and forks keep memory and running processes.

Moving to Runtime

Vercel Sandbox code, in JavaScript or Python, runs on Runtime once the import changes, without a Vercel project or token:

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

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

Northflank's service and deployment plan have no counterpart to port: each sandbox is a single Sandbox.create(). Commands, files and teardown follow map the calls.

A coding agent can do the change from the one instruction in migration, on a branch, tested on the free trial. Vercel users who run npx withruntime switch --from vercel before their first top-up get it matched with credit, up to $100. Longer reads: Runtime vs Vercel Sandbox, Runtime vs Northflank.

Sources

Vercel Sandbox pricing and Northflank's sandboxes page rechecked 25 September 2026; the rest checked 23 September 2026.

• Vercel Sandbox pricing, Understanding Vercel Sandboxes
• Northflank pricing, Northflank sandboxes, Sandboxes on Northflank
• Runtime pricing

Facts on this page were checked on 25 September 2026.