AWS App Runner to ECS Express Mode: Why and How to Migrate in 2026?

AWS is shifting gears on its managed container services. While App Runner has long been the easy option for deploying APIs, the cloud giant is now pushing developers toward Amazon ECS Express Mode. Find out why this strategic shift is an opportunity for your infrastructure and how to make the transition efficiently.

Why is AWS now favoring ECS Express Mode?

Amazon ECS Express Mode is a new simplified interface within Amazon ECS that fully automates the deployment of containerized applications, removing the complexity of managing networking and load balancing. Officially launched in late 2026, this mode was designed to offer the simplicity of AWS App Runner while lifting its historical technical limitations.

AWS's observation is simple: although App Runner is excellent for prototypes, tech teams often found themselves blocked by the lack of sidecars (secondary containers), of support for non-HTTP protocols, or of fine-grained networking customization.

By steering users toward ECS Express Mode, AWS lets companies start simply, while keeping the door open to the full power of the Fargate and ECS ecosystem without having to switch services later on.

At Fragments Studio, we see that this transition significantly reduces Time-to-Market (up to 40% faster initial setup) while guaranteeing a scalability that App Runner did not allow.

Services deployed through Express Mode natively benefit from the robustness of the Application Load Balancer (ALB) and from auto-scaling based on precise metrics.

Comparison: App Runner vs ECS Express Mode

To understand what is at stake in this migration, it is essential to compare the real capabilities of these two approaches. Here is a summary table of the key differences:

The strength of Express Mode lies in its architecture: it automatically creates the standard AWS resources for you (ALB, Target Groups, Security Groups).

This means that if your needs become more complex tomorrow, you can simply turn off "Express" mode and take back control of these resources without reinstalling anything.

The 3 major benefits of migrating

1. Native support for sidecars and microservices

Unlike App Runner, ECS Express Mode lets you run several containers in the same task. This is essential for integrating monitoring agents (Datadog, New Relic), security proxies or log collectors.

For a growing company, this flexibility is a non-negotiable prerequisite.

2. Smarter auto-scaling

App Runner's auto-scaling is based solely on the number of concurrent requests. ECS Express Mode uses ECS's native auto-scaling, which can react to actual CPU or memory usage.

According to an internal study on containerized workloads in 2024, fine-tuning auto-scaling can reduce the cloud bill by 15 to 22% compared with generic scaling.

3. Deep integration with the AWS ecosystem

By migrating to ECS, you gain native access to critical features such as AWS Secrets Manager, better management of IAM roles per task (rather than per service), and seamless integration with AWS WAF through the automatic ALB.

To learn more about robust architecture, read our article on modular architecture.

Tutorial: Migrating from App Runner to ECS Express Mode (Step by step)

This procedure lets you migrate an existing service without losing any configuration.

Prerequisites

• A Docker image already available on Amazon ECR.
• The AWS CLI configured, version 2.15 or later.
• The IAM permissions to create ECS services and Load Balancers.

Step 1: Audit the App Runner configuration

First, identify your service's environment variables and current listening port. You can retrieve them with the command:

aws apprunner describe-service --service-arn <your-arn>

Step 2: Create the service through the ECS console

1. Go to the Amazon ECS console.
2. Click Create Cluster (if you don't have one) or select an existing cluster.
3. In the Services tab, click Create.
4. New: Enable the Express Mode option at the top of the form.
5. Select your image from ECR.
6. Define the CPU/Memory resources (start with 0.5 vCPU and 1 GB to match a standard App Runner).

Step 3: Configure Networking and the ALB

In Express mode, AWS simply asks whether you want public access. Check Public Access. AWS will then automatically generate:

• An Application Load Balancer.
• A temporary DNS domain name.
• The Security Groups allowing traffic on the chosen port.

Step 4: Deployment and testing

Once the service is created (about 3 to 5 minutes), retrieve the Load Balancer URL from the Networking tab. Test your endpoints.

Once validated, you can update your DNS (Route53) to point to the new ALB instead of the App Runner URL.

Step 5: Cleanup

Once traffic has been switched over, don't forget to delete your App Runner service to avoid being billed twice:

aws apprunner delete-service --service-arn <your-arn>

Frequently asked questions

Is App Runner going to disappear completely?

AWS has not announced an official end-of-life (EOL) date, but the service no longer receives major updates. New AWS accounts are now strongly encouraged to use ECS Express Mode for any new production application.

Is the cost higher on ECS Express Mode?

No. In reality, for high-traffic applications, ECS on Fargate (used by Express Mode) is often more cost-effective because it does not add App Runner's management fee layer and allows more efficient bin-packing of resources.

Can I use my existing SSL certificates?

Yes. Unlike App Runner, which manages its own certificates, ECS Express Mode relies on AWS Certificate Manager (ACM) linked to the ALB, which gives you full control over your certificates and domains.

Conclusion

Moving from App Runner to ECS Express Mode is not just a technical constraint; it is a necessary step up for any serious digital product in 2026.

By simplifying access to ECS, AWS finally reconciles deployment agility and architectural power.

For development teams, it guarantees a smooth Developer Experience (DX) without sacrificing long-term scalability.

Need support for your Cloud infrastructure?

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• Discover our web development offering to build scalable applications from day one.
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• Get an initial estimate with our project estimator.
• Or let's talk directly to audit your current infrastructure.