Development environments / Release alternative

A Release.com alternative for the machine behind a long-running coding agent

Release provisions application environments from source and templates, including services and data dependencies for previews, staging and production. Compare this multi-service deployment platform with the persistent Linux runtime where an agent installs tools, edits a repository and accumulates work across tasks.

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

When Release fits

Release fits teams needing production-like full-stack environments, source/CI integration, application deployment and data fixtures. Keep its cloud/account integration and preview workflow when those are the main requirements; a generic agent machine does not replace the deployed application stack.

When to consider Sandbox0

Consider Sandbox0 for compatible Linux agent execution with complete writable-RootFS persistence, online expansion and supported access to files while compute is paused. Retain or implement application deployment, preview URLs, databases and test-data orchestration separately.

Capabilities

Release and Sandbox0: what persists?

Feature comparison with documentation and verification status
Environment and runtime lifetimeReleasePermanent environments do not automatically expire; ephemeral retention is separately controlled by plan and account policy.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 filesReleaseApplication data, datasets and infrastructure have their own configured retention; these sources do not establish one durable agent disk.View evidence ↗Sandbox0The writable RootFS survives successful checkpoints, including software, system configuration, dependencies, and user data.Read documentation →
Whole RootFSReleaseReproducible application environments do not establish preservation of every mutable Linux system path.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 stateReleaseThe documented Instant Dataset pause/resume path applies to ephemeral environments; do not generalize it to every Release workload.View evidence ↗Sandbox0Pause compute between tasks; resume on available capacity. Default resume starts fresh processes from the saved filesystem.Read documentation →
Memory and process stateReleaseDataset/environment pausing does not establish arbitrary process-memory checkpoints.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.

Release can maintain application and dataset environments, but those are not evidence of automatic online growth of a complete durable agent RootFS. Check the actual volume/database policy and agent-machine requirements independently.

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 →

Permanent and ephemeral environment policies are different

Release documents permanent environments separately from expiring previews. Its expiry guide lists a three-day ephemeral default and plan-controlled overrides, while the create-environment guide uses a seven-day example/default. Confirm the configured account policy and source revision rather than impose one universal lifetime. Permanent application environments also do not establish arbitrary agent-process memory continuity.

Source 1 ↗Source 2 ↗Source 3 ↗

The documented pause path has an Instant Dataset scope

The pause guide is specifically about Instant Datasets in ephemeral environments, with manual pause/resume and daily/weekend schedules. It states that only ephemeral environments can use this path and that a pause can take several minutes. This is useful cost control, but its storage and process coverage should not be generalized to every workload or production environment.

Source 1 ↗

The current price page requests a custom Enterprise quote

The current Enterprise pricing page asks customers to discuss their stack, team and usage for a custom quote. Obtain the applicable platform, infrastructure, dataset and support terms together. Historical hourly plans and free-environment allowances do not establish a currently purchasable offer.

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.

Release

Pricing reviewed 2026-10-18

Current Enterprise platform offer
Custom quote based on stack, team and usage
Rate source ↗
Customer-cloud infrastructure
Underlying cloud resources billed separately
Confirm the supported cloud and included service scope in the agreement.
Rate source ↗
Instant Dataset, support and integration terms
Confirm in the Enterprise agreement
Rate source ↗

The current Enterprise offer requires a custom quote. Historical hourly plans, old free-environment allowances and separate Release AI Agent preview terms do not establish its price. Compare the complete agreement plus infrastructure, data and agent-runtime costs.

Check current Release 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 Release

  1. Inventory application templates, services, datasets, previews, permanent environments, expiration/pause settings, account/cloud integration and effective commercial terms.
  2. Port compatible Linux agent execution to Sandbox0 while retaining Release or another platform for application deployment and test environments.
  3. Test full-stack behavior separately from agent system state, RootFS growth, paused file access, process restart expectations and combined agreement/cloud/runtime costs.

Common questions

Is Sandbox0 a drop-in Release replacement?

Evaluate API compatibility and product scope. These products serve different core workflows, so a change may require a different architecture.

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.release.com/ ↗docs.release.com/reference-documentation/environment-expiration.md ↗docs.release.com/getting-started/create-an-environment ↗docs.release.com/guides-and-examples/advanced-guides/pausing-instant-datasets/pausing-resuming-environments.md ↗web.release.com/pricing ↗Sandbox0 RootFS capacity →

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