Agent sandboxes / Archil alternative

An Archil sandbox alternative for a long-lived agent computer

Archil persistent sandboxes already keep the root filesystem and can pause with memory intact. The comparison is not folder persistence versus an entire computer: it is session deadlines, storage metering, capacity behavior, and integration with Archil’s data platform.

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

When Archil fits

Archil fits teams that want Firecracker sandboxes close to versioned disks, object-backed data, and serverless file tools. A persistent root disk, memory pause, OCI images, and full guest-kernel facilities support substantial agent environments.

When to consider Sandbox0

Consider Sandbox0 when the runtime’s primary job is a long-lived per-user Linux computer with automatic RootFS expansion and files accessible during compute pauses. Its default lifetime deadlines are disabled, and retained data uses incremental-storage billing.

Capabilities

Archil and Sandbox0: what persists?

Feature comparison with documentation and verification status
Environment and runtime lifetimeArchilEach powered-on session is capped at 24 hours, then pauses; resume begins a new session with preserved processes.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 filesArchilPersistent root-disk state survives stop/start and pause/resume.View evidence ↗Sandbox0The writable RootFS survives successful checkpoints, including software, system configuration, dependencies, and user data.Read documentation →
Whole RootFSArchilThe root filesystem lives on an Archil disk and retains installed packages and files.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 stateArchilPause retains disk and memory; stop retains only disk.View evidence ↗Sandbox0Pause compute between tasks; resume on available capacity. Default resume starts fresh processes from the saved filesystem.Read documentation →
Memory and process stateArchilPause and eligible forks retain processes and memory; host failure loses volatile state and requires boot from disk.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.

Archil explicitly persists the root disk and advertises unrestricted paid disk size generally. The reviewed sandbox lifecycle does not specify automatic online RootFS expansion as free space runs low; verify root-disk geometry and resize behavior separately from mounted data-disk capacity.

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 →

A reusable sandbox still has powered-on session deadlines

Archil limits each session to at most 24 hours, then pauses with disk, memory, and processes preserved. Resume starts a new session. Direct process connections affect optional idle expiry, but do not remove the hard deadline. Plan for the pause and reconnect path in unattended jobs.

Source 1 ↗

Persistent root disks and additional mounts are distinct

Installed packages and files survive Archil stop/start and pause/resume. Stop boots fresh processes later; pause retains memory. Extra mounted disks survive sandbox deletion and can be shared, while deletion removes the root disk. Forking with attached disks also needs a deliberate sharing policy.

Source 1 ↗

Monthly minimums and storage layers affect the total

Archil usage counts toward its monthly minimum instead of adding a subscription fee on top. Active-storage metering covers the high-speed cache, while archive storage applies separately to filesystems without a customer-owned bucket. Serverless tool calls include execution and should not receive a second sandbox CPU charge.

Source 1 ↗Source 2 ↗Source 3 ↗

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.

Archil

Pricing reviewed 2026-10-18

Sandbox CPU
$0.055 per vCPU-hour
Rate source ↗
Sandbox memory
$0.020 per GiB-hour
Rate source ↗
Active storage
$0.20 per GiB-month
Time-weighted active data in the high-speed storage layer.
Rate source ↗
Archive storage
$0.025 per GB-month
Additional for filesystems that do not synchronize to customer-owned buckets.
Rate source ↗
Developer / Team minimum spend
$10 / $500 per month
Usage counts toward the minimum; it is not a fee added to all usage.
Rate source ↗
Separate serverless tool calls
$0.05 per 1,000 calls
Execution included; storage and applicable transfer remain separate.
Rate source ↗

The displayed usage rates apply to Developer and Team; Enterprise is custom. Free has hard included-usage caps. Data leaving Archil is $0.07/GB on the published paid plans. General paid-disk no-size-limit wording does not establish the sandbox root disk’s automatic growth behavior.

Check current Archil 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 Archil

  1. Record powered-on deadlines, idle policy, root files, extra mounted disks, forks, and any paused memory state.
  2. Port OCI environment, commands, services, credentials, and network rules; test tools that depend on guest-kernel container facilities against gVisor.
  3. Validate an unattended multi-day agent, reconnect behavior, installed packages, automatic RootFS growth, and compute-independent file access; estimate retained data using the correct storage meter.

Common questions

Is Sandbox0 a drop-in Archil 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.archil.com/compute/sandboxes/introduction ↗archil.com/pricing ↗docs.archil.com/administration/billing ↗docs.archil.com/concepts/metering ↗Sandbox0 RootFS capacity →

Related comparisons

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