E2B gives agents an isolated place to run the code they write. Each sandbox boots in its own lightweight virtual machine (microVM), and software development kits (SDKs) for Python and JavaScript connect it to an agent loop. For production deployments, compare providers on isolation, billing, persistence, and scale.
At production scale, compare E2B's subscription fee, runtime billing, and concurrency limits. The Pro plan costs $150 per month, plus usage billed for every second a sandbox runs, including waits for model responses. It includes 100 concurrent sandboxes, expandable to 1,100 through paid add-ons. E2B documents official Python and JavaScript SDKs, while its self-hosted Embed distribution runs on a single machine.
The six alternatives below differ in isolation and pause behavior. The comparison also covers when staying on E2B makes sense.
Copy link to headingHow to compare E2B alternatives
Compare isolation, state-on-pause, session limits, and bring-your-own-cloud (BYOC) support when choosing an E2B replacement. Check environment restore times and advertised boot times, especially when an agent needs to install dependencies and save files. An April 2026 engineering report describes how Vercel reduced Vercel Sandbox’s p75 snapshot restore times from over 40 seconds to under 1 second, with a 95% cache hit rate across its observed workload.
For each property, check the following:
Isolation boundary: Whether code runs on its own kernel inside a microVM, on a userspace kernel such as gVisor that handles application system calls, or directly on the host's kernel through a container.
State on pause: Whether the filesystem, memory, or neither survives a pause or stop, how lifecycle operations differ, and how long saved state lasts.
Session limits: How long one session can run, what the default timeout is, and how much central processing unit (CPU) capacity and memory one sandbox can use.
BYOC support: Whether the sandboxes can run in your own cloud account in production.
Review the isolation boundary first. Ordinary containers, sandboxed runtimes, and microVMs expose different attack surfaces. Choose based on your workload and security requirements.
The table compares each tool with E2B on these four properties:
E2B, Vercel Sandbox, and Fly.io Sprites all use Firecracker. To choose between them, compare persistence, credential controls, deployment options, and the rest of each provider's security architecture.
Copy link to headingVercel Sandbox
Vercel Sandbox is a managed execution environment that runs each sandbox in its own Firecracker microVM, with JavaScript and Python SDKs and a sandbox command-line interface (CLI). Per-plan limits cap sessions at 45 minutes on Hobby or 24 hours on Pro and Enterprise.
Vercel Sandbox fits persistent agent workspaces and high-concurrency code execution. Files and installed dependencies survive between sessions, while Active CPU billing excludes time spent waiting on model responses or external services.
Pros:
Dedicated kernel per sandbox: Each sandbox runs in its own microVM with a dedicated filesystem and its own network namespace.
Active CPU billing: Time spent waiting on model calls, network requests, or databases doesn't count toward CPU charges.
Persistent by default: Sandboxes snapshot their filesystem on stop. The SDK restores it when the next operation needs a running session.
Cons:
No documented BYOC or self-hosting option: Vercel's BYOC on Amazon Web Services (AWS) covers Vercel Functions, not Sandbox.
Memory follows CPU: Each virtual CPU (vCPU) includes 2 GB of memory, so you can't provision memory independently of CPU.
No memory snapshots or GPU option: A stop saves files but ends running processes, and GPU jobs need a separate provider.
Copy link to headingDaytona
Daytona is a sandbox service that runs Linux containers by default, with Linux VM, Windows, GPU, and macOS sandbox types available. It bills allocated CPU, memory, and storage per second, with listed CPU and memory rates that match E2B's.
It suits teams that want those compute rates, a larger starting credit, and a choice of container or VM isolation. Pricing is pay-as-you-go with no base fee, at $0.0504 per vCPU-hour.
Pros:
Large free credit: A $200 starting compute credit supports prototyping without a credit card.
Memory-intact pause and fork: VM sandboxes pause with memory preserved and fork into independent copies.
BYOC and desktop access: Daytona documents bring-your-own-compute, remote desktop access, and computer use.
Cons:
Containers by default: Container sandboxes share the host kernel and can't pause. Choose the VM type when your workload requires a dedicated guest kernel or memory-preserving pause.
Default per-sandbox ceiling: The stable-release documentation lists organization sandbox limits of 4 vCPUs, 8 gibibytes (GiB) of memory, and 10 GiB of disk. GPU sandboxes have separate quotas.
Disk held while stopped: Stopped container sandboxes occupy disk quota until archived.
Copy link to headingModal
Modal is a serverless compute platform with Python as its primary SDK. Its Sandboxes run on gVisor, a userspace kernel from Google, or on a VM runtime with its own Linux kernel.
It fits Python-first teams already deploying functions on Modal who want sandboxes and GPU workloads in the same account. Starter costs $0 plus compute with $30 of monthly credit, and Team costs $250 a month plus compute.
Pros:
Renewing credit: $30 of compute renews every month on Starter.
GPU concurrency on a $0 plan: Starter allows 10 GPU containers at once, with usage billed separately.
Long maximum session: The
timeoutparameter raises the 5-minute default to as much as 24 hours.
Cons:
Runtime restrictions: Set
runtime="vm"when you need a dedicated Linux kernel. GPU sandboxes requireruntime="gvisor". An unset runtime lets Modal choose.Short-lived memory state: Memory snapshots (in alpha) expire 7 days after creation and can't be extended. Sandboxes with memory snapshots enabled can't use GPUs.
Beta SDKs outside Python: The JavaScript and Go SDKs are still in beta.
Copy link to headingNorthflank
Northflank is a deployment platform that runs sandboxes alongside services, databases, and jobs, in Northflank's cloud or your own account. On Northflank Cloud, CPU sandboxes use microVMs and GPU sandboxes use gVisor automatically. In your own cloud, isolation depends on the configured runtime class.
It suits teams that need sandboxes in a specific cloud account or data center alongside their other services. A free Sandbox tier includes two services, two jobs, and one database. Pay-as-you-go compute starts at $0.01667 per vCPU-hour.
Pros:
BYOC breadth: Self-service BYOC covers AWS, Google Cloud Platform (GCP), Azure, and on-premises clusters, with bare metal where eligible.
Low listed vCPU rate: The starting CPU rate is about a third of Daytona's per-vCPU-hour rate. Compare memory, storage, and deployment charges separately.
Service-style lifecycle: Pause and resume sandboxes through the API. Pausing stops compute charges.
Cons:
BYOC isolation setup: Installing sandbox runtimes in your cluster doesn't enable isolation on its own. A cluster default or workload tag must select a sandbox runtime class.
Ephemeral file loss: Move files to an attached volume before pausing. Pausing discards ephemeral storage.
Processes end on pause: Attached-volume data survives, but running processes and terminal sessions must restart after resuming.
Copy link to headingFly.io Sprites
A Fly.io Sprite is a persistent Firecracker microVM workspace with a 100 GB volume. Agents can return to the same working environment between tasks. Each Sprite has its own HTTPS URL, and Connectors keep credentials for services like GitHub outside the workspace.
It suits coding agents that keep a repository checked out between tasks. CPU and memory bill on use, plus storage, with no per-Sprite fee.
Pros:
Persistent disk with checkpoints: Files survive suspension, and the filesystem checkpoints itself when idle or on graceful shutdown.
Usage-based billing: A Sprite that sits idle costs only its storage.
Wake on request: An incoming request to its URL wakes the Sprite.
Cons:
Process state isn't durable: Warm suspension preserves processes, but cold suspension drops memory and requires processes to restart.
Automatic idle suspension: A Sprite stops compute billing when it enters the warm state. Register and refresh the Tasks API to keep background work running.
No documented BYOC option: Sprites run on Fly.io's managed infrastructure.
Copy link to headingRunloop
Runloop is a service for coding agents that runs isolated VMs called devboxes, with Python and TypeScript SDKs and a CLI. Agent Gateways grant devboxes gateway tokens and inject real credentials into server-side requests. Runloop reports SOC 2 Type II compliance.
It supports coding-agent teams that retain the devbox disk state between tasks. New accounts get a $50 trial credit, Basic is free plus usage, and Pro costs $250 a month plus usage.
Pros:
No compute charge while suspended: A suspended devbox stops billing CPU and memory, and only storage continues.
Snapshots and Blueprints on every plan: Devbox snapshots and reusable devbox templates are available from Basic up.
VPC deployment on Enterprise: Enterprise includes a deployment option for your VPC.
Cons:
Suspend gated to Pro: Suspend and resume require the $250 Pro plan after the trial.
Unspecified VM implementation: The Devbox overview describes VM isolation without naming the hypervisor.
Higher CPU rate: The listed devbox CPU rate exceeds Daytona's and Northflank's starting rates.
Copy link to headingHow do you choose the right E2B alternative?
Choose isolation based on the workload's threat model and required capabilities. Ordinary containers share the host's kernel, so a kernel exploit can affect other workloads on the host. MicroVMs provide a dedicated guest kernel, while gVisor handles application system calls in a separate userspace kernel. Evaluate either approach for unreviewed agent code, including compatibility, network controls, and disclosed vulnerabilities; the microVMs versus containers guide explains the architectural tradeoffs.
Copy link to headingWhen to stay on E2B
E2B remains an option when you need to preserve memory, deploy in your own cloud, or run desktop agents. A full-memory pause preserves files and running processes. Enterprise BYOC supports AWS, Google Cloud, or Azure with the same SDK, CLI, and API interfaces. E2B also supports Ubuntu desktops for computer use and secret injection into matching outbound HTTPS requests outside the sandbox.
Test memory preservation before relying on it. Auto-pause on timeout is opt-in because onTimeout defaults to "kill". If a previous snapshot prevents timeout-triggered memory auto-pause, E2B retries for about two minutes before falling back to a filesystem-only pause. The next resume reboots the sandbox and loses memory state.
Copy link to headingVercel Sandbox compared with E2B
When replacing E2B, compare isolation, credentials, billing, state, and scale. The following sections cover Vercel Sandbox's behavior and tradeoffs in each area.
Copy link to headingPublicly tested microVM
Security reviews should examine the isolation architecture, independent assessments, and disclosed vulnerabilities. Vercel Sandbox provides a dedicated guest kernel inside each Firecracker microVM.
Vercel ran a $1M public security challenge and commissioned an architecture review by Trail of Bits. Trail of Bits found its virtualization boundary sound. Researchers filed 1,285 reports over two weeks, and Vercel paid $242,000 in bounties. The work uncovered vulnerabilities and led to security improvements. No reports demonstrated access to customer files, secrets, or application data.
Copy link to headingEgress controls and credential brokering
Passing an API key into a sandbox as an environment variable exposes it to generated code, which can read, print, commit, or transmit it. Credential brokering keeps the real secret outside the VM and injects it into matching outbound requests. Restrict which services and operations the sandbox can access.
E2B also supports credential brokering at egress, in beta. Compare how their policies handle allowed and denied traffic. The Vercel sandbox firewall has three modes (allow-all by default, deny-all, and user-defined). You can update policies at runtime without restarting the process.
Denied address ranges take precedence over allowed domains and address ranges on Vercel, while E2B lets an allow rule win when an address appears in both lists. Vercel's sandbox egress firewall is available on every plan, including the Hobby plan.
Vercel Sandbox's credential brokering and request transformations don't apply to Postgres connections. Keep database credentials in a trusted service outside the sandbox and expose a restricted API to generated code.
Copy link to headingActive CPU billing for model-bound loops
An agent loop can spend much of its session waiting on model responses without using CPU. Wall-clock billing charges for allocated vCPU throughout those waits. Active CPU billing charges for CPU usage, while provisioned memory continues to bill for the full running session.
Copy link to headingPersistence on by default
Preserving the working directory between prompts avoids repeating dependency installations and other setup steps. Persistent sandboxes save the filesystem on stop. The SDK restores it when the next operation needs a running session. Set persistent: false for one-off jobs that don't need a saved state.
Stopping and resuming resets the session cap, so a sandbox can run across multiple sessions as long as it retains a usable snapshot. Sandbox.getOrCreate() retrieves a sandbox by name, and Sandbox.fork() creates a sandbox from its current snapshot. Snapshot storage costs $0.08 per GB-month. Snapshots expire 30 days after their last use by default unless you configure a different retention period.
Persistence covers files only. Running processes don't survive a stop, so use an onResume hook to restart services the agent needs. E2B and Daytona VM sandboxes can instead resume processes from memory when a full-memory pause succeeds.
Copy link to headingConcurrency for fan-out workloads
Fan-out workloads, such as parallel evaluations, scale with both sandbox count and sandbox size. Vercel Pro and Enterprise allow up to 10,000 concurrent sandboxes, compared with 10 on Hobby.
The allocation rate increases with sustained usage. An idle Pro team starts at 150 vCPUs per minute, enough for 18 sandboxes with 8 vCPUs each. The rate increases by 500 vCPUs per minute until it reaches 5,000 vCPUs per minute. Sandbox runs on Hive, the Firecracker infrastructure also used by Vercel's internal build product.
Copy link to headingTest your agent loop before you migrate
Before migrating from E2B, run a long task with pauses and resumes to verify that it retains the state it needs. Measure CPU utilization per session, check egress policies, and test whether generated code can read credentials. Vercel Sandbox fits CPU workloads that run many sandboxes in parallel. Teams requiring BYOC or GPUs need another provider for those workloads.
Follow the Vercel Sandbox quickstart to connect your agent loop, or browse Vercel templates to start an application from a template.
Copy link to headingFrequently asked questions about E2B alternatives
Copy link to headingWhat is the best free E2B alternative?
Vercel Hobby includes monthly usage quotas and pauses sandbox creation when a quota is exhausted, without charging for additional Hobby usage. Its snapshot and drive storage quotas are lifetime limits. Daytona advertises the largest one-time compute credit at $200 without a credit card. E2B Hobby provides a $100 one-time credit.
Copy link to headingIs E2B good for self-hosted agent sandboxes?
E2B Embed supports self-hosting on a single machine. It packages the open-source runtime under Apache-2.0, with the same SDK and API interfaces, and supports internal workloads on a trusted network. E2B also offers managed deployment in your own cloud through Enterprise BYOC.
Copy link to headingHow much does E2B cost compared with alternatives?
For small workloads that require E2B Pro limits, its $150 monthly base fee can outweigh compute charges. A 2-vCPU Vercel Sandbox with 4 GB of memory running for 10 minutes, with both CPUs fully active for two minutes, costs about $0.0227 in Vercel CPU and memory charges in iad1.
Copy link to headingDo E2B alternatives save memory state when paused?
E2B preserves memory by default, subject to its timeout auto-pause fallback. Daytona preserves it on VM pauses, while Modal memory snapshots expire after seven days and exclude GPUs. Sprites preserve processes while warm, but drop memory when cold. Vercel Sandbox and Runloop preserve disk state, while Northflank retains attached-volume data.