Agent sandboxes / Solari alternative

A Solari sandbox alternative for a persistent Linux agent

Solari provides code sandboxes, browser sessions, and graphical VMs. Its default dedicated sandbox owns a microVM, while shared sandboxes expose a narrower writable filesystem. Keep those modes separate when evaluating an agent that installs tools across the root filesystem.

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

When Solari fits

Solari fits teams combining browser automation, VM screens, stateful code execution, snapshots, and sandbox tools under one credit balance. Dedicated and hardened modes provide a different environment from the cheaper shared process-tree mode.

When to consider Sandbox0

Consider Sandbox0 when an agent’s installed packages, system configuration, and outputs should remain in one durable writable RootFS that expands online. Its supported paused-file interface also separates persistent data access from waking execution.

Capabilities

Solari and Sandbox0: what persists?

Feature comparison with documentation and verification status
Environment and runtime lifetimeSolariThe pricing table lists 24-hour Professional sessions and unlimited Enterprise sessions, with shorter limits on other plans.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 filesSolariPause and snapshots retain disk state; independent volumes are separate.View evidence ↗Sandbox0The writable RootFS survives successful checkpoints, including software, system configuration, dependencies, and user data.Read documentation →
Whole RootFSSolariDedicated mode owns its filesystem; shared mode has read-only system directories and must be assessed separately.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 stateSolariPause/resume saves and restores the sandbox; pending capture can delay a resume.View evidence ↗Sandbox0Pause compute between tasks; resume on available capacity. Default resume starts fresh processes from the saved filesystem.Read documentation →
Memory and process stateSolariA snapshot carries complete disk and memory images.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.

Solari documents persistent snapshots, volumes, and isolation-specific writable paths. The reviewed lifecycle does not establish automatic expansion of a complete mounted RootFS as free space runs low; shared-mode system directories are read-only.

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 →

Shared filesystem restrictions do not apply to every Solari sandbox

Solari shared mode makes system directories such as /usr, /etc, and /var read-only and directs installations into writable project paths. Dedicated is the default and gives the sandbox its own filesystem. Compare the chosen isolation mode rather than assigning shared-mode restrictions to the whole product.

Source 1 ↗

Snapshots retain disk and memory with explicit lifecycle conditions

Solari snapshots carry complete disk and memory state. Snapshot and revert require a running machine, while pause already saves state for later resume. Independent volumes use separate mount and lifecycle rules, so record both the machine image and external datasets before migration.

Source 1 ↗Source 2 ↗

Plan credits and snapshot storage affect the usable runtime budget

Solari’s plan table sets included credits, session limits, and plan-specific CPU and memory rates. Retained snapshot storage is separately charged above an organization allowance. A paid plan’s included credits fund usage; counting the full resource bill again without using those credits would overstate cost.

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.

Solari

Pricing reviewed 2026-10-18

Starter plan
$20 per month
Includes $20 monthly credit; plan table lists a five-hour session limit.
Rate source ↗
Starter sandbox CPU
$0.035 per vCPU-hour
Rate source ↗
Starter sandbox memory
$0.011 per GB-hour
Rate source ↗
Professional plan
$200 per month
Includes $200 monthly credit; sandbox CPU is $0.0245/vCPU-hour and memory $0.0077/GB-hour.
Rate source ↗
Retained snapshot storage
$0.05 per GB-month
Organization’s first 10 GB free; prorated daily, including snapshots promoted to templates.
Rate source ↗
Separate graphical VM screen
Additional $0.02 per hour
Rate source ↗

Compute rates depend on plan; Free and Enterprise have different published rows. Monthly included credits do not roll over, while purchased top-ups do not expire. The snapshot-storage policy took effect October 1, 2026. Preserve the vendor’s GB units and distinguish code sandboxes from browser-session and screen charges.

Check current Solari 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 Solari

  1. Record isolation mode, plan session limit, snapshot IDs, templates, volumes, code-session state, and any separate browser profiles.
  2. Export files and recreate packages, services, credentials, and network access in a Sandbox0 template; assess graphical or browser-specific tooling separately.
  3. Test system installs, repeated tasks, RootFS growth, pause/resume, and supported file access during a compute pause, then compare the full credit and storage budget.

Common questions

Is Sandbox0 a drop-in Solari 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.getsolari.com/sandboxes ↗docs.getsolari.com/snapshots ↗docs.getsolari.com/volumes ↗docs.getsolari.com/pricing ↗Sandbox0 RootFS capacity →

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