re:Invent 2025 - Launch web applications in seconds with Amazon ECS Express Mode

Amazon Elastic Container Service (Amazon ECS) has been the foundation for containerized workloads on AWS for over 11 years. The service currently provisions around 3 billion tasks per week across 38 AWS Regions, and 65% of new customers running containerized workloads on AWS start with it. Express Mode does not replace Amazon ECS. It is a feature of ECS, built on the same underlying service, that automates the configuration of the supporting infrastructure so developers can focus on writing application code.

Malcolm Featonby, Senior Principal Engineer at AWS, and Thomas Fahrner, Software Engineer at AWS, presented a live demonstration of Express Mode in action, walking through creation, update, and deletion of a running web application entirely from the AWS CLI and console.

What Express Mode automates

A standard ECS web service requires configuring an Application Load Balancer (ALB), listener rules, target groups, security groups (for both the ALB and the service), a task definition, an ECS service, auto-scaling targets and policies, CloudWatch alarms, and networking. Express Mode reduces the developer's required inputs to three: a container image, a task execution role (permissions the application needs to run), and an infrastructure role (permissions for ECS to provision resources on your behalf).

From those three inputs, Express Mode builds a complete, production-ready stack. It provisions an AWS Fargate-based ECS service, an ALB with HTTPS on port 443 and SSL/TLS termination, auto-scaling policies, Amazon CloudWatch monitoring and alarms, security groups with least-privilege rules between the ALB and the ECS service, and a unique application URL on the *.ecs.<region>.on.aws domain. There is no additional charge for Express Mode itself. You pay only for the underlying resources consumed, such as Fargate compute, ALB, CloudWatch logs and metrics, and data transfer.

One notable cost optimization: Express Mode shares a single ALB across up to 25 services using host-header-based listener rules. Each service maintains isolation while the ALB cost is distributed across all services sharing that network configuration. This applies to both public and private HTTPS applications.

The --monitor-resources flag in the AWS CLI gives you a real-time view of every resource being provisioned on your behalf during create, update, and delete operations. From the ECS console, the Resources tab on any Express Mode service shows the same information, making it straightforward to understand exactly what infrastructure is backing your application at any point in time.

Full lifecycle management

Express Mode is not limited to the creation experience. Fahrner demonstrated an in-place update that changed both the container image and the container port for a running service. Updating a container port requires coordinated changes across the ALB security group egress rules, target group configuration, task definition, and service security group. Express Mode orchestrates all of those in a single update command, with no downtime.

Updates use canary-based deployment by default. Five percent of traffic is shifted to the new task while 95% remains on the prior revision. After a bake period, traffic shifts fully to the new revision. CloudWatch alarms monitor 4xx and 5xx error rates from the ALB throughout the deployment. If error rates exceed the threshold, Express Mode rolls back to the prior service revision automatically.

The delete operation is similarly orchestrated. Express Mode identifies which resources are unique to the service being removed and which are shared across other services. Shared resources such as the cluster and ALB are retained. Resources unique to the deleted service, such as target groups, scaling policies, and listener rules, are drained and deprovisioned. The Resources tab shows this process in real time.

Full ECS flexibility, not a replacement

Because Express Mode is a feature of ECS and not a separate service, all standard ECS functionality remains available. You can open the task definition for any Express Mode service, add sidecar containers, adjust resource limits, push a new revision, and update the service through Express Mode using the same API. Custom auto-scaling policies based on metrics other than CPU utilization (such as request count per target per minute) are available at creation and update time. The Express Mode API coexists with direct ECS API calls, so teams can use Express Mode for the streamlined lifecycle operations while retaining access to the full depth of ECS configuration when needed.

Express Mode is available today in all AWS Regions where Amazon ECS and Fargate are supported. You can create and manage Express Mode services through the Amazon ECS console, AWS CLI, SDKs, AWS CloudFormation, AWS CDK, and Terraform.

To get started, visit the Amazon ECS Express Mode documentation or watch the full re:Invent 2025 session recording.