Agent sandboxes / Hopx alternative

A Hopx alternative for the storage and lifecycle your agent needs

Hopx already documents two useful returning-agent paths: pause retains memory and processes, while stop retains the filesystem and restarts runtime state. Compare disk growth and billing conditions without reducing those capabilities to ephemeral code execution.

Start buildingCompare capabilities ↓

Reviewed 2026-10-18 · Published by the Sandbox0 team

When Hopx fits

Hopx fits teams that want sandbox execution, desktop automation, streaming/background work, templates, and explicit pause/stop choices. Its timeout guide supports creation without an expiration setting for indefinite work, subject to effective account policy.

When to consider Sandbox0

Consider Sandbox0 for automatic online growth of a durable complete writable RootFS and supported persistent-file operations while compute stays paused. Match the actual image, network, desktop, and process-continuity requirements before switching.

Capabilities

Hopx and Sandbox0: what persists?

Feature comparison with documentation and verification status
Environment and runtime lifetimeHopxCreation without a timeout is documented as indefinite; configured expiry destroys the sandbox.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 filesHopxStop retains the filesystem; kill/deletion is a different operation.View evidence ↗Sandbox0The writable RootFS survives successful checkpoints, including software, system configuration, dependencies, and user data.Read documentation →
Whole RootFSHopxThe state guide describes filesystem preservation on stop and complete state on pause, rather than only a synchronized repository.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 stateHopxPause/resume retains full state; stop/start keeps filesystem with fresh runtime state.View evidence ↗Sandbox0Pause compute between tasks; resume on available capacity. Default resume starts fresh processes from the saved filesystem.Read documentation →
Memory and process stateHopxPause explicitly preserves memory, variables, and running processes.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.

Hopx documents filesystem retention and state controls, but the reviewed lifecycle and timeout sources do not establish automatic online expansion of the complete mounted RootFS.

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.

See paused file operations →

Pause and stop preserve different state

Hopx distinguishes full-state pause, including variables and running processes, from filesystem-only stop. Both are different from deletion. Choose the required path deliberately rather than treating every resume as either a cold boot or an exact-memory continuation.

Source 1 ↗

The expiry setting is an independent deletion control

The timeout guide allows creating without a timeout and extending a deadline for an existing sandbox. It warns that expiry automatically destroys the sandbox. An example one-hour timeout is not a universal maximum; conversely, file retention does not override configured destruction.

Source 1 ↗

Published unit rates and example totals need separate treatment

The price page lists CPU, allocated RAM, and storage rates per second. Its headline examples are rounded and do not clearly itemize all listed resources. Use the actual meters and effective parked-storage policy rather than repeat a low one-hour example as an all-in quote.

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.

Hopx

Pay as you go · no subscription

$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

Adds the published per-second vCPU and allocated GiB rates. The introductory $200 credit is excluded; storage remains a separate per-second meter.

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

Calculation and billing assumptions

Hopx: $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 Hopx rate source ↗Sandbox0 rates ↗

Hopx

Pricing reviewed 2026-10-18

CPU
$0.000014 per vCPU-second
Rate source ↗
Allocated RAM
$0.0000045 per GiB-second
Rate source ↗
Storage
$0.00000003 per GiB-second
Rate source ↗
Recurring subscription
No subscription or minimum commitment advertised
Rate source ↗

Preserve GiB resource labels and second-level meters. Confirm which states retain a storage charge and how allocation is measured. The page’s rounded $0.05 one-hour example is not used as a complete CPU+RAM+storage calculation; pricing headlines alone do not prove every idle-running state is free.

Check current Hopx 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 Hopx

  1. Record paused versus stopped state, expiry policy, installed tools, files, templates, and any desktop/API dependencies before exporting data.
  2. Port compatible images, lifecycle, executions, files, credentials, and networking to the target integration.
  3. Validate actual system paths, growing RootFS data, paused file access, memory requirements, and all effective CPU/RAM/storage meters.

Common questions

Is Sandbox0 a drop-in Hopx 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.hopx.ai/core-concepts/sandboxes/managing-state ↗docs.hopx.ai/core-concepts/sandboxes/timeout ↗hopx.ai/pricing/ ↗Sandbox0 RootFS capacity →

Related comparisons

Agent 37 vs Sandbox0 →AgentComputer vs Sandbox0 →ainclave vs Sandbox0 →Alibaba Cloud Agent Sandbox / FC / AgentRun vs Sandbox0 →Alibaba Cloud AgentBay vs Sandbox0 →Amika vs Sandbox0 →