Agent sandboxes / E2B alternative

An E2B alternative for agents that keep growing

E2B already preserves the filesystem and memory through pause/resume. The next questions for a long-running agent are how its root filesystem grows, how you access files while compute is paused, and how runtime limits affect your application.

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Reviewed 2026-10-19 · Published by the Sandbox0 team

When E2B fits

Choose E2B when its code-interpreter integrations, SDK ecosystem, and default memory-preserving pause fit your application. Pro publishes a 24-hour continuous runtime limit; Enterprise offers different arrangements.

When to consider Sandbox0

Consider Sandbox0 for a per-user cloud computer whose installed software, system configuration, and data must persist together, with online RootFS growth on enabled templates and Files API access while compute is paused.

Capabilities

E2B and Sandbox0: what persists?

Feature comparison with documentation and verification status
Environment and runtime lifetimeE2BHobby permits one hour and Pro twenty-four hours of continuous runtime. Pause/resume resets that limit; paused state has no automatic expiry.View evidence ↗Sandbox0ttl and hard_ttl default to 0 (disabled). Configure idle pause and deletion policies for the same persistent sandbox identity; an idle running sandbox still accrues compute charges.Read documentation →
Persistent filesE2BPaused files are retained indefinitely until explicit deletion; running timeouts have a separate policy.View evidence ↗Sandbox0The writable RootFS survives successful checkpoints, including software, system configuration, dependencies, and user data.Read documentation →
Whole RootFSE2BThe full sandbox filesystem is captured; filesystem-only mode reboots instead of restoring RAM.View evidence ↗Sandbox0Persistence extends beyond /workspace to paths such as /usr/local, /etc, and /home. Runtime tmpfs and virtual filesystems are excluded.Read documentation →
Release compute, keep stateE2BDefault pause saves memory and disk; filesystem-only mode changes restoration semantics.View evidence ↗Sandbox0Pause compute between tasks; resume on available capacity. Default resume starts fresh processes from the saved filesystem.Read documentation →
Memory and process stateE2BNormal memory pause restores processes. A documented rolling auto-pause fallback can preserve disk only.View evidence ↗Sandbox0Experimental memory checkpoints can preserve compatible process state. Use memory: true on both pause and resume on a compatible deployment. A filesystem checkpoint alone does not preserve running processes.Read documentation →

Online RootFS growth

On growth-enabled images, Sandbox0 automatically expands the writable RootFS as free space runs low, within a configured sparse logical ceiling up to 64 TiB. Agent processes keep running. Growth is enabled in the qualified Cloud region; confirm activation for other regions. Existing images and snapshots retain their captured storage geometry. The ceiling is logical capacity, not preallocated host disk.

E2B already preserves the whole filesystem. Its included 10 GiB Hobby and 20 GiB Pro allowances are not an automatic online RootFS-growth specification. Confirm effective disk capacity and resize behavior separately from memory snapshots and plan allowances.

Files while compute is paused

Sandbox0's Files API reads persistent files without resuming compute. Filesystem-only pauses also permit edits; retained-memory pauses are read-only and reject mutations with 409. SSH, SFTP, file watching, and runtime-only mounts require running compute.

E2B’s auto-resume example reads a file by waking the paused sandbox; enabled file reads and writes count as resume activity. This differs from leaving guest compute stopped. Sandbox0 supports offline reads and filesystem-only mutations, while memory-paused mutations return 409.

See paused file operations →

E2B persistence includes the whole filesystem

E2B documents preservation of both files and running process state. Treat persistence as a shared capability. Sandbox0 defaults to filesystem-only pause; preserving compatible process state requires explicit experimental memory pause and resume.

Source 1 ↗

Plan for a filesystem that outgrows its starting size

E2B lists 10 GiB of included storage on Hobby and 20 GiB on Pro. Sandbox0 can grow XFS online within a sparse device ceiling up to 64 TiB on growth-enabled imports. The ceiling is logical capacity, not reserved local disk; existing generations retain their geometry.

Source 1 ↗Source 2 ↗

Budget the plan fee separately from usage

E2B Pro adds a monthly $150 fee to metered compute. Sandbox0 bills configured memory and running time, plus retained incremental storage. Storage charges continue while paused; compute charges stop. Compare concurrency, CPU allocation, and checkpoint requirements before choosing a tier.

Source 1 ↗Source 2 ↗

Choose pause mode and failure handling deliberately

Default pause saves RAM and files; filesystem-only mode cold-boots on resume. In a region-by-region rollout, a snapshot backlog can delay automatic memory pause. After roughly two minutes of continued refusal, the documented fallback saves the filesystem without RAM. Inspect the pause event and make initialization recoverable if process continuation matters. External service connections also need reconnection after a pause.

Source 1 ↗

File access can resume the machine

E2B can wake a paused sandbox automatically for file reads, file writes, commands or application traffic. That is convenient request-driven execution. It is a different contract from accessing persistent files while guest compute remains stopped; include the wake behavior in lifecycle and billing expectations.

Source 1 ↗

Pricing

Compare billing models, then price your workload

CPU allocation, memory, billing minimums, disk, plan fees, and supported workload differ. These meters are not equal-performance machine quotes. Confirm region, resource units, and included allowances before estimating a total.

Same size. Lower compute cost.

2 vCPU · 4 GiB RAM · 730 running hours / month

Save $77.09 / month

The same CPU and memory allocation, with runtime aggregated across sessions. Monthly allowances and credits below are applied to this workload.

E2B

Hobby · usage billing

$120.89

$0.1656/hour before monthly allowances

Sandbox0

Pay as you go · no monthly plan fee

$43.80

$0.06/hour · 63% lower in this example

Hobby’s default 2 vCPU / 4 GiB allocation is used. Its one-hour session limit still applies; 730 hours are accumulated across sessions. The one-time sign-up credit is excluded.

Compute and stated plan fees only. Storage, network, taxes and one-time credits are excluded; hardware and throughput can differ.

Calculation and billing assumptions

E2B: $120.888 compute after 0 included vCPU-hours and 0 included GiB-hours, plus $0.00 plan fee, minus $0.00 applied monthly credit.

Sandbox0: 4 GiB × 730 hours × its published compute rate. CPU uses the Cloud allocation shown on the pricing page.

Includes compute and the selected plan. Excludes storage, network, taxes, one-time grants and negotiated discounts. Assumes this workload can use the full listed monthly allowances. CPU and memory counts do not guarantee equal hardware or throughput.

Checked E2B rate source ↗Sandbox0 rates ↗

E2B

Pricing reviewed 2026-10-19

CPU
$0.000014 per vCPU-second
Rate source ↗
Memory
$0.0000045 per GiB-second
Rate source ↗
Pro plan
$150/month plus usage
Hobby permits 1-hour continuous sessions; Pro permits 24-hour sessions. Limits and Enterprise terms differ.
Rate source ↗

Included disk is 10 GiB on Hobby and 20 GiB on Pro. Compute is billed while running; plan charges and concurrency add-ons must be budgeted separately.

Check current E2B pricing ↗

Sandbox0

$0.015/GiB-hour compute (billed by the second at approximately $0.000004167/GiB-second), plus $0.02/GiB-month of retained incremental RootFS and memory checkpoint data. Shared base images and platform recovery retention are excluded; paused sandboxes accrue storage charges only.

Compute / GiB-hour
$0.015
Retained data / GiB-month
$0.02
Paused compute
$0.00
Understand storage billing →

Before migrating from E2B

  1. Inventory E2B templates, installed packages, filesystem contents, and any live interpreter state that must survive.
  2. Port SDK execution, file, ingress, and secret handling to Sandbox0; choose filesystem-only or explicit experimental memory pause deliberately.
  3. Test a task that grows beyond its initial disk, then inspect files while paused and verify the expected processes after resume.

Common questions

Is Sandbox0 a drop-in E2B replacement?

Evaluate API compatibility and product scope. A shared sandbox category does not make SDKs, lifecycle semantics, or limits interchangeable.

Does keeping files also keep a running agent?

Filesystem state and volatile process state are separate. Sandbox0 requires explicit compatible memory checkpoints to preserve running processes; its default filesystem resume starts fresh processes.

Sources and review scope

The Boat team's Battleships directory is the discovery source. References below describe the product and plan discussed on this page. Check current availability, regional terms and billing units before migrating. Where the cited material does not establish a capability or price, the comparison identifies that uncertainty.

Battleships research record ↗docs.e2b.dev/sandbox/persistence ↗e2b.dev/pricing ↗/docs/sandbox/template/configuration ↗/pricing ↗docs.e2b.dev/sandbox/auto-resume ↗docs.e2b.dev/faq/sandbox-lifetime ↗Sandbox0 RootFS capacity →

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