AWS has recently introduced CloudFormation express mode, a deployment option that can reduce infrastructure deployment times by marking stack operations complete once resource configuration is applied, rather than waiting for full resource stabilization.
In express mode, CloudFormation marks an operation complete once the create, update, or delete API call succeeds. As a result, resources may still be initializing, not yet ready to serve traffic, or still being deleted.
The new option does not require template changes, supports existing CloudFormation features such as nested stacks and change sets, and is intended for faster development workflows where immediate traffic readiness is not required. Enabling Express mode on a parent stack automatically applies Express mode to all nested stacks. Channy Yun, principal developer advocate at AWS, writes:
Express mode benefits two primary use cases: iterative development workflows and production scenarios where you are comfortable with eventual stabilization. These use cases include iterating on infrastructure configurations during development, testing individual components of your application, and AI-assisted infrastructure development that benefits from sub-minute feedback loops.
Until now, every CloudFormation deployment included mandatory stabilization checks after resources were configured to ensure they were ready to handle traffic before it was shifted. CloudFormation express mode is not the default and is enabled in the AWS CLI using the following option:
--deployment-config '{"mode": "EXPRESS"}'
According to the announcement, creating an SQS queue with a dead-letter queue takes over a minute in standard mode but less than 10 seconds in express mode. Similarly, deleting a Lambda function with network interface attachments goes from 20–30 minutes to seconds. Yun adds:
If you need resources to be fully operational before proceeding with traffic or testing, continue using the default deployment behavior, which performs stabilization checks before completing.
The operational friction of waiting for CloudFormation deployments has been a long-term complaint from the AWS community, with several developers saying in the past they preferred Terraform because of the experience. On LinkedIn, Yan Cui, AWS Hero and serverless expert, argues:
The new CloudFormation Express mode is useful for dev environments (...), but I don't agree with the AI framing "AI-assisted infrastructure development that benefits from sub-minute feedback loops". A fast feedback loop has always mattered! It's a major reason why so many have preferred Terraform over CloudFormation for years. Time spent waiting for CloudFormation deployment to finish is no different from time spent waiting for an AI agent to finish.
Other practitioners, while appreciating the new option, highlight the tradeoffs. Michał Piszczek, CTO at Archdesk, warns:
Rollback disabled by default is the detail people will skip past. Fine for AI agents provisioning throwaway stacks, risky for anything a human has to debug at 3 am.
In a separate announcement, AWS also expanded CloudFormation's pre-deployment validation to run automatically on every stack create and update operation, helping detect template errors before resources are provisioned. The update also introduces additional validation checks, a new cdk validate command for AWS CDK projects, and an option to disable validation for specific deployments when needed.
Both express mode and the new validation are available in all regions where CloudFormation is supported, with no opt-in required and without extra costs.