Application platforms / Azure Container Apps alternative

Azure Container Apps alternative for persistent agents

Azure Container Apps runs managed applications and jobs with Consumption or Dedicated compute. Container files are temporary; replica-scoped and external filesystem mounts have different retention. Its Dynamic Sessions and newer Sandboxes are separate execution surfaces and should not be assigned the ordinary app container’s storage contract.

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Reviewed 2026-10-19 · Published by the Sandbox0 team

When Azure Container Apps fits

Choose Container Apps for application deployment, scaling, networking and Azure integration. Dedicated workload profiles and managed code sessions serve different needs from an agent’s persistent Linux computer.

When to consider Sandbox0

Consider Sandbox0 for compatible agent execution with retained system paths and online whole-RootFS growth. Application ingress, scaling, revisions, session pools and Azure services remain integrations to retain or implement.

Capabilities

Azure Container Apps and Sandbox0: what persists?

Feature comparison with documentation and verification status
Environment and runtime lifetimeAzure Container AppsReplica scaling and idle billing follow the app configuration. Scaling to zero releases Consumption compute but does not retain temporary container root files.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 filesAzure Container AppsAzure Files can retain explicitly mounted data independently of a container or replica.View evidence ↗Sandbox0The writable RootFS survives successful checkpoints, including software, system configuration, dependencies, and user data.Read documentation →
Whole RootFSAzure Container AppsOrdinary app container filesystem changes disappear on shutdown/restart.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 stateAzure Container AppsApplication scaling does not establish arbitrary machine checkpoint/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 stateAzure Container AppsThe ordinary app storage contract does not establish arbitrary RAM capture; Sandboxes is separate.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.

Container Apps can mount durable Azure Files and scale application resources. Those capabilities differ from automatic online growth of the complete persistent Linux RootFS, including writes outside mounted application volumes.

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.

Azure Files remains accessible through its storage interfaces when app replicas are absent. That is selected mounted data, not an offline file API for the temporary root filesystem of a stopped app container.

See paused file operations →

Container and replica storage stop at different boundaries

Files in a container disappear when that container shuts down or restarts. EmptyDir files survive a container restart within the same replica but only last for that replica’s lifetime. Azure Files provides a separate mounted durable filesystem, rather than automatic retention of every writable system path.

Source 1 ↗

Scale to zero is different from keeping an idle replica

A zero-replica revision has no Consumption resource charges. A running minimum replica can receive reduced idle rates only under specific CPU, network and request conditions. Serverless GPU apps do not qualify for those idle rates; they are always billed for active use.

Source 1 ↗

Separate the platform’s compute products

Dedicated plans bill provisioned workload-profile resources and management fees. Dynamic Sessions has its own session-hour meter. Azure Container Apps Sandboxes offers stateful snapshots through a different resource type, covered in its own comparison; ordinary app storage rules should not be generalized to it.

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.

Azure Container Apps

Pricing reviewed 2026-10-19

Consumption active CPU, East US
$0.000024 per vCPU-second
Standard active usage meter; grant and account terms apply.
Rate source ↗
Consumption active memory, East US
$0.000003 per GiB-second
Rate source ↗
Consumption idle CPU, East US
$0.000003 per vCPU-second
Only eligible minimum replicas receive idle treatment.
Rate source ↗
Consumption idle memory, East US
$0.000003 per GiB-second
Idle memory remains billed; this is not zero-replica storage.
Rate source ↗

East US USD retail rates are references, not negotiated invoices. Consumption grants, request meters, Dedicated management, session products, storage and network charges have separate scope. Stopping app compute does not turn temporary container files into durable data.

Check current Azure Container Apps 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 Azure Container Apps

  1. Inventory compute plan, replicas, revisions, local/EmptyDir/Azure Files paths and any Dynamic Sessions or Sandboxes usage.
  2. Export required state and run compatible agent tools on Sandbox0, retaining needed app ingress and Azure integrations.
  3. Test system-path retention, growing files, paused operations and total active/idle/request/storage/profile costs.

Common questions

Is Sandbox0 a drop-in Azure Container Apps 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 ↗learn.microsoft.com/en-us/azure/container-apps/storage-mounts ↗learn.microsoft.com/en-us/azure/container-apps/billing ↗azure.microsoft.com/en-us/pricing/details/container-apps/ ↗prices.azure.com/api/retail/prices ↗Sandbox0 RootFS capacity →

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