Together labels this the deprecated CodeSandbox-based legacy SDK and recommends together-sandbox for new integrations. This page compares the legacy offering, not a verified shutdown of all CodeSandbox services. Read the source ↗

Agent sandboxes / CodeSandbox SDK alternative

CodeSandbox SDK alternative

CodeSandbox SDK already supports VM filesystem persistence and memory snapshots. Together’s current documentation labels this SDK deprecated and points new integrations to together-sandbox. Compare the legacy contract you actually use with Sandbox0’s durable whole RootFS and automatic online growth, rather than assuming every sandbox product starts from an empty workspace.

Start buildingCompare capabilities ↓

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

When CodeSandbox SDK fits

The legacy SDK remains relevant to teams maintaining existing CodeSandbox templates, browser sessions and development-tool integrations under their effective account terms. Together’s guide still describes custom-plan and CodeSandbox self-service access, while recommending its successor for new work.

When to consider Sandbox0

Consider Sandbox0 when an agent’s complete writable RootFS should grow online as tools and data accumulate, with supported file operations while compute stays paused. Port SDK/lifecycle calls deliberately; existing CodeSandbox development UI and browser-session features are separate integration work.

Capabilities

CodeSandbox SDK and Sandbox0: what persists?

Feature comparison with documentation and verification status
Environment and runtime lifetimeCodeSandbox SDKNot established in this reviewSandbox0ttl 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 filesCodeSandbox SDKVM filesystem persistence is explicitly documented for the legacy SDK.View evidence ↗Sandbox0The writable RootFS survives successful checkpoints, including software, system configuration, dependencies, and user data.Read documentation →
Whole RootFSCodeSandbox SDKThe guide describes persisted VM filesystem state and customizable Docker/Dev Container environments, not only a designated workspace.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 stateCodeSandbox SDKHibernation/resume is supported, with separately documented CLEAN boot paths.View evidence ↗Sandbox0Pause compute between tasks; resume on available capacity. Default resume starts fresh processes from the saved filesystem.Read documentation →
Memory and process stateCodeSandbox SDKMemory snapshot/restore is documented; CLEAN boots do not restore the previous execution image.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.

CodeSandbox’s documented VM filesystem durability and memory snapshots are acknowledged. The reviewed legacy reference does not establish automatic online RootFS expansion as one agent’s installed tools and data grow. Confirm current storage geometry and limits instead of inferring them from memory snapshots or editor quotas.

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.

The legacy guide documents filesystem access in a connected development environment and hibernation. It does not establish the same supported whole-RootFS read/write contract while compute stays paused; connecting/resuming and offline file access are different lifecycle operations.

See paused file operations →

VM persistence and memory capture are real capabilities

Together’s legacy guide explicitly describes memory snapshot/restore and VM filesystem persistence, plus Docker/Dev Container customization. Templates contain memory and filesystem state, so a created sandbox can continue a prepared server. Installed tooling and prepared services can be reused, subject to the distinct resumed-snapshot and CLEAN boot paths.

Source 1 ↗Source 2 ↗

A CLEAN boot needs different application handling

The guide distinguishes a resumed snapshot from a CLEAN start. CLEAN can occur after shutdown or restart, an expired snapshot or another failure; the platform rebuilds the development environment instead of resuming the prior execution image. Check bootupType and rerun initialization where needed rather than assuming every connection restores the same processes.

Source 1 ↗

Legacy credit prices and current successor prices are different contracts

The current legacy reference lists $0.01486 per VM credit and size-specific hourly consumption, rounded up to whole minutes. Concurrency and base-plan fees are separate. Its worked Scale example includes a $170 base fee and 1,100 credits, but the effective account allowance should be confirmed; these are not the new together-sandbox SDK’s rates.

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.

CodeSandbox SDK

Pricing reviewed 2026-10-18

Legacy VM credit
$0.01486 per credit
Runtime rounds up to whole minutes; resource sizes consume different credits/hour.
Rate source ↗
Legacy Pico
$0.0743/hour; 2 cores, 1 GB RAM
Five credits/hour in the published legacy table.
Rate source ↗
Legacy Nano
$0.1486/hour; 2 cores, 4 GB RAM
Ten credits/hour; this is a resource tier, not a universal sandbox-hour rate.
Rate source ↗
Scale reference example
$170/month base fee
The guide’s example includes 1,100 credits and lists 250-VM Scale concurrency; verify your current workspace terms.
Rate source ↗

These are Together’s published legacy SDK rates, separate from its successor product. The guide lists Build as free with ten concurrent VMs, but a free base plan does not imply unlimited runtime. Account plans, included credits, concurrency, rounding and custom discounts affect the bill.

Check current CodeSandbox SDK 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 CodeSandbox SDK

  1. Identify legacy CodeSandbox versus the successor SDK, template/Docker configuration, account rates, filesystem changes and CLEAN-boot initialization hooks.
  2. Export required files and port SDK, command, port and lifecycle integrations to a Sandbox0 template; rebuild any required collaboration/browser-session layer.
  3. Test system-package retention, memory-mode compatibility, failure recovery, online RootFS growth, paused files and the actual resource/storage budget.

Common questions

Is Sandbox0 a drop-in CodeSandbox SDK 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.together.ai/docs/together-code-sandbox-legacy ↗github.com/codesandbox/codesandbox-sdk ↗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 →