Vercel Sandbox vs E2B
Pick Vercel Sandbox if you already build on Vercel and your workloads are idle-heavy — Active CPU billing means you don't pay while sandboxes wait on I/O, and there's no separate vendor to manage. Pick E2B if you need multi-region flexibility, self-hosting, or CPU-intensive workloads: its ~$0.05/vCPU-hr wall-clock rate is well under Vercel's $0.128/vCPU-hr, and it isn't confined to a single region (Vercel runs sandboxes only in iad1 as of mid-2026).
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Side by side
Vercel Sandbox
E2BThis is an unusually clean comparison because the isolation layer is identical: both Vercel Sandbox and E2B run each sandbox in a Firecracker microVM with a dedicated kernel, both are explicitly marketed for AI-agent and untrusted code, and neither supports GPUs (a Firecracker limitation both inherit). The differences are billing model, ecosystem, and operational flexibility.
Billing basis — the subtle big one. E2B bills wall-clock resource time: ~$0.000014/vCPU-s (about $0.05/vCPU-hr) plus RAM, whether the CPU is busy or waiting. Vercel bills Active CPU at $0.128/vCPU-hr — idle and I/O-wait time isn't charged for CPU, though provisioned memory ($0.0212/GB-hr), sandbox creations ($0.60 per million), data transfer, and storage are metered separately. The crossover depends on your duty cycle: a sandbox that pegs its vCPU pays roughly 2.5x more per hour on Vercel, while an agent sandbox that spends most of its life waiting on LLM calls or network I/O may pay substantially less. Model your actual workload before assuming either is cheaper.
Region and deployment. Vercel Sandbox runs in a single region (iad1) as of mid-2026, and it is not self-hostable — the open-source repo is SDK and CLI only, with the isolation engine living exclusively on Vercel's infrastructure. E2B's core is Apache-2.0 with a documented Terraform self-hosting path on AWS, GCP, Azure, or bare Linux. If data residency, latency to non-US-East users, or vendor exit paths matter, E2B is the only viable answer of the two.
Session limits and persistence. The caps are similar in shape: Vercel allows 45 minutes on Hobby and 24 hours on Pro/Enterprise; E2B allows 1 hour on Hobby and 24 hours on Pro. Persistence models differ slightly: Vercel sandboxes are persistent by default, with automatic filesystem snapshot on stop and restore on resume. E2B's pause/resume goes further, preserving memory state as well as the filesystem, indefinitely — useful when an agent's in-process state (not just its files) needs to survive.
Free tiers and plan economics. Vercel's Hobby tier is a recurring monthly allowance: 5 Active-CPU hours, 420 GB-hrs memory, 5,000 creations, 15GB storage per month, with usage pausing when exceeded. E2B's Hobby is a one-time $100 credit, then pay-as-you-go. For higher limits, Vercel Pro's sandbox usage draws from the general $20/mo platform credit, while E2B Pro is a $150/mo base fee that unlocks 24-hour sessions and 100 concurrent sandboxes (versus 20 on Hobby).
SDKs and integration. Both offer JS/TS and Python SDKs plus a CLI (E2B adds a REST API). The real integration difference is platform gravity: Vercel Sandbox is wired into Vercel projects and billing, which is a feature if that's your stack and dead weight if it isn't.
Bottom line. Same isolation technology, different business wrapper. Vercel Sandbox is the low-friction choice for teams already on Vercel with bursty, I/O-bound agent workloads that benefit from Active CPU billing. E2B is the standalone specialist: cheaper for CPU-bound work, memory-preserving pause/resume, no single-region constraint, and the only one of the pair you can run on your own infrastructure.