Render Sandboxes is early access and enabled only for selected workspaces. APIs, defaults, limits, and production suitability should be confirmed with Render. Read the source ↗

Agent sandboxes / Render alternative

A Render sandbox alternative for a returning agent computer

Render now has an early-access Sandbox product in addition to its application platform. It can capture writable filesystem state or runtime state, including memory, for a new sandbox. Those snapshots differ from persistent disks attached to ordinary Render services and from a continuously retained agent environment.

Start buildingCompare capabilities ↓

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

When Render fits

Render fits teams that want its deployment platform, managed data services, and access to the new sandbox APIs. Its runtime snapshots can preserve execution state where the selected workspace is enabled and restoration meets the snapshot’s resource requirements.

When to consider Sandbox0

Consider Sandbox0 when an application needs the same durable writable RootFS across tasks, online filesystem growth, and supported persistent-file operations while compute stays paused. Keep any web deployment, database, or broader Render platform services as separate architectural decisions.

Capabilities

Render and Sandbox0: what persists?

Feature comparison with documentation and verification status
Environment and runtime lifetimeRenderEarly-access Sandbox timeout is 24 hours; that is a limit, not unlimited continuous execution.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 filesRenderReusable snapshots retain saved state until expiry; ordinary sandbox termination discards unsaved filesystem changes.View evidence ↗Sandbox0The writable RootFS survives successful checkpoints, including software, system configuration, dependencies, and user data.Read documentation →
Whole RootFSRenderSandbox filesystem snapshots capture the writable filesystem; restore is into a new sandbox and retention limits apply.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 stateRenderThe reviewed path restores snapshots into a new sandbox; a stable-identity stop/resume contract is not established.View evidence ↗Sandbox0Pause compute between tasks; resume on available capacity. Default resume starts fresh processes from the saved filesystem.Read documentation →
Memory and process stateRenderExplicit runtime snapshots capture writable filesystem, memory, and CPU state, with matching-plan restore requirements.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.

Render service disks preserve a selected mount, while Sandbox snapshots preserve saved writable state. The reviewed guides do not establish automatic online growth of the complete live Sandbox RootFS. Sandbox0’s enabled growth policy applies to that whole-system persistence scope.

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 →

Terminated files and reusable snapshots have different lifetimes

Render Sandboxes are ephemeral on termination, but filesystem snapshots capture the writable filesystem and runtime snapshots also capture CPU/memory state without stopping the source. Restores create a new sandbox in the same group, and runtime restores must use the saved plan. Snapshots expire after three days by default, so they are not an indefinite retention contract.

Source 1 ↗

Service disks and sandbox capacity should not be conflated

Ordinary paid Render services can attach a persistent disk that retains only the selected mount path across restarts and deploys. The separate early-access Sandbox limits currently list 10 GB filesystem storage, a 24-hour timeout, and Oregon availability, with some resource limits raisable by request. A service disk allowance is not evidence of automatic whole-RootFS growth on Sandboxes.

Source 1 ↗Source 2 ↗

Workspace fees are not the Sandbox compute rate

Render’s current public price page lists workspace fees plus compute and separately prices app disks, databases, and workflow resources. The reviewed Sandbox early-access guide does not publish a numeric Sandbox runtime rate. Confirm effective Sandbox charges and entitlements rather than use an application instance, app disk, or Workflow task rate as a substitute.

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.

Render

Pricing reviewed 2026-10-18

Hobby workspace
$0 per month plus compute
Workspace fee, not a promise of free Sandbox runtime.
Rate source ↗
Pro workspace
$25 per month plus compute
Rate source ↗
Scale workspace
$499 per month plus compute
Rate source ↗
Sandbox runtime
Confirm effective early-access pricing with Render
No numeric Sandbox rate is published in the reviewed guide; separate app and Workflow prices are not applied here.
Rate source ↗

The public workspace prices and Sandbox early-access terms describe different parts of the bill. Verify actual compute, snapshot retention/storage, egress, concurrency, and enabled account access. Do not treat a renewable runtime snapshot as indefinite free storage or apply app-disk pricing to Sandbox snapshots without confirmation.

Check current Render 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 Render

  1. Export needed Sandbox files or available snapshots before expiry, and inventory ordinary service disks and platform services separately.
  2. Rebuild compatible tools in a Sandbox0 template and port sandbox command/file, credential, network, and lifecycle integration; preserve unrelated app/database infrastructure as needed.
  3. Validate repeated system state, growing RootFS data, paused file access, process-continuity requirements, resource limits, and the effective Sandbox price rather than an unrelated platform meter.

Common questions

Is Sandbox0 a drop-in Render 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 ↗render.com/docs/sandboxes ↗render.com/docs/disks ↗render.com/pricing ↗Sandbox0 RootFS capacity →

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