Agent sandboxes / Declaw alternative

A Declaw sandbox alternative for a persistent Linux agent

Declaw already captures filesystem, memory, and process state in snapshots, and has separate persistent volumes and security-proxy services. Compare its template-bound resources and lifecycle limits with a RootFS that grows automatically while an agent runs.

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

When Declaw fits

Declaw fits teams that want sandbox execution integrated with credential policies, guardrails scanning, memory snapshots, and shared file volumes. Its prepaid wallet separates sandbox credits from guardrails credits before charging the shared paid balance.

When to consider Sandbox0

Consider Sandbox0 when installed software, configuration, and accumulated outputs should live on one durable RootFS with automatic online expansion and supported paused file access. Model and policy-layer services remain separate integration choices.

Capabilities

Declaw and Sandbox0: what persists?

Feature comparison with documentation and verification status
Environment and runtime lifetimeDeclawPro permits sessions up to 72 hours; Free is limited to one hour and Enterprise terms differ.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 filesDeclawIndependent volumes survive a killed sandbox; pause and snapshots retain the sandbox filesystem separately.View evidence ↗Sandbox0The writable RootFS survives successful checkpoints, including software, system configuration, dependencies, and user data.Read documentation →
Whole RootFSDeclawA snapshot captures complete filesystem, memory, and process state.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 stateDeclawExplicit pause/resume exists; a failed pause can ultimately kill the sandbox and auto-resume is not yet enforced.View evidence ↗Sandbox0Pause compute between tasks; resume on available capacity. Default resume starts fresh processes from the saved filesystem.Read documentation →
Memory and process stateDeclawSnapshots retain RAM and running processes for restored sandboxes.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.

Declaw resource sizing is fixed by the selected template, and the plan table caps template disk. Its snapshot and volume features do not establish automatic online expansion of the entire 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 →

Memory snapshots and independent volumes serve different lifetimes

Declaw snapshots capture RAM, filesystem, and processes for new sandboxes. Volumes outlive sandbox destruction and provide copy-at-boot or live shared files. A killed sandbox loses its own filesystem, so choose a snapshot or volume for the state the application needs later.

Source 1 ↗Source 2 ↗

Resource sizing and timeouts are part of the template workflow

Declaw rejects per-sandbox resource overrides and takes CPU, memory, and disk from the template. Free and Pro have different session-duration limits. Timeout can pause instead of kill, but the lifecycle guide says failed pause attempts can ultimately kill the sandbox, and auto_resume is not yet enforced.

Source 1 ↗Source 2 ↗

Pro requires recharge, not a second flat fee

Pro requires at least $100 in deposits each calendar month; unused paid balance carries over. Sandbox resource charges and ML guardrails scans draw from separate initial grants and then the same paid wallet. Do not add the recharge commitment again as a subscription charge on top of the consumed balance.

Source 1 ↗Source 2 ↗

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.

Declaw

Pricing reviewed 2026-10-18

Running CPU
$0.0504 per vCPU-hour
Rate source ↗
Running memory
$0.0162 per GB-hour
Rate source ↗
Provisioned running overlay disk
$0.0000000424 per GB-second
The guide also expresses this as approximately $0.110/GB-month; pause ends compute metering.
Rate source ↗
Pro recharge commitment
$100 in deposits per calendar month
A balance commitment, not an extra flat fee; unused paid balance carries over.
Rate source ↗
PII / prompt-injection ML scans
$0.0006 per scan
Other scanners have separate rates; local regex scans are free.
Rate source ↗

The guide meters provisioned resources at second-level resolution with periodic settlement. Initial sandbox and guardrails grants are one-time rather than monthly. Confirm retained snapshots and volume storage separately, and preserve GB units rather than silently treating them as GiB.

Check current Declaw 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

A 4 GiB agent, 100 running hours

$6.00 compute

4 GiB × 100 hours, billed by the second. Keeping 20 GiB of billable incremental data for a full billing month adds $0.40. CPU is derived from memory by the platform; choose a tier that fits your workload.

Understand storage billing →

Before migrating from Declaw

  1. Inventory templates, pause/snapshot state, attached volumes and their sharing modes, session deadlines, and guardrails policies before killing any source.
  2. Export required data and port the image, commands, credentials, network rules, and any security services the application depends on.
  3. Test a long agent task, growing system packages and files, paused file operations, process requirements, and sandbox plus guardrails billing.

Common questions

Is Sandbox0 a drop-in Declaw 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.declaw.ai/features/snapshots ↗docs.declaw.ai/features/volumes ↗docs.declaw.ai/features/sandboxes ↗docs.declaw.ai/platform/plans ↗docs.declaw.ai/platform/billing ↗Sandbox0 RootFS capacity →

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