Runnable demos for Azure Container Apps Express and ACA Sandboxes.
| Demo | Description |
|---|---|
demos/aca-express-cold-start |
Browser dashboard that measures real-world cold-start latency for ACA Express instances |
demos/aca-sandboxes |
End-to-end CLI demo showing suspend/resume, snapshotting, rollback, and egress control |
| Workflow | Trigger |
|---|---|
aca-express-cold-start-publish |
Push to main touching demos/aca-express-cold-start/** — builds and pushes the container image to GHCR |
Azure Container Apps Express is an environment tier in Public Preview that removes infrastructure decisions from deployment. There is no environment to provision, no networking to configure, no scaling rules to write — you bring a container image and Express handles everything else.
Key characteristics:
- Instant provisioning — apps running in seconds, not minutes
- Sub-second cold starts — fast enough for interactive UIs and on-demand agent endpoints
- Scale to and from zero — automatic, no configuration required
- Per-second billing — pay only for what you use, same as the ACA consumption plan
- Production-ready defaults — ingress, secrets, environment variables, and observability built in
Express is designed for two audiences: developers who want to ship fast (SaaS apps, APIs, web dashboards, prototypes) and agent-first systems that deploy endpoints on demand (MCP servers, tool-use endpoints, workflow APIs).
Preview regions: East Asia and West Central US. More regions coming.
Express is built on ACA Sandboxes internally — the platform layer that provides fast startup from prewarmed pools.
📖 Announcing ACA Express (blog) · Express FAQ
ACA Sandboxes (Early Access) provide fast, secure, isolated compute environments with built-in suspend and resume capabilities. They are a first-class resource type (Microsoft.App/SandboxGroups) in Container Apps, alongside apps, jobs, and dynamic sessions.
Where Dynamic Sessions provide a managed execution experience that abstracts away infrastructure, Sandboxes give you direct, programmable control over isolated compute environments — including state snapshots, persistent storage, and networking policies.
| Dynamic Sessions | ACA Sandboxes | |
|---|---|---|
| Lifecycle control | Managed by session pool | You manage: create, suspend, resume, delete |
| State across tasks | ✗ ephemeral | ✅ suspend/resume |
| Snapshots | ✗ | ✅ named, restorable |
| Persistent storage | ✗ | ✅ Azure Blob + Data Disk volumes |
| Egress policies | Basic isolation | ✅ Allow/deny/transform/rewrite |
| Credential injection | ✗ | ✅ Via Transform rules |
Early Access: Resources created during Early Access may not be compatible with future Public Preview releases. Requires
Container Apps SandboxGroup Data Ownerrole.