AWS re:Invent 2025 - Debug Lambda functions deployed in cloud like never before (CNS367)

Transforming the Serverless Developer Experience

Challenges in Serverless Development

• Setting up a local development environment for Lambda functions can take 30-40 minutes due to manual steps like installing tools, configuring credentials, and setting up dependencies.
• Testing multi-service serverless application workflows locally is difficult, often requiring deployment to the cloud, which slows down iterations.
• Debugging issues that only occur in the cloud environment, such as VPC configurations, IAM permissions, and service-specific behaviors, can be time-consuming using traditional approaches.

New Features to Enhance Serverless Development

Seamless Console to IDE Transition

• Enables transferring code and configuration from the AWS Management Console to the local VS Code IDE with a single click.
• Eliminates the need for manual setup, allowing developers to start coding in their local environment in under 30 seconds.
• Enables managing dependencies using package managers like npm and pip, and using development tools like linters and formatters.

Local Stack Integration

• Integrates the local stack emulator directly into the VS Code IDE, allowing developers to set up and test serverless application workflows locally.
• Enables 75-80% faster local testing iterations by eliminating the need to deploy to the cloud for testing.
• Allows discovering issues early in the development cycle by testing against locally emulated AWS services and resources.

Remote Debugging for Lambda Functions

• Enables debugging Lambda functions running in the AWS cloud directly from the local VS Code IDE.
• Provides the IDE experience with breakpoints, step-through debugging, and variable inspection, combined with the production fidelity of real AWS services, VPC, and IAM.
• Reduces debugging time by 80-85% compared to traditional methods, from 20-30 minutes per bug to 3-5 minutes.

Business Impact and Use Cases

• These new features work together to accelerate the serverless development lifecycle by 40% or more.
• Developers can maintain flow and productivity by getting fast feedback cycles in the inner loop of their development process.
• The ability to debug cloud-specific issues directly in the IDE bridges the gap between the inner and outer development loops.
• Use cases include identifying VPC configuration issues, IAM permission problems, and service-specific behaviors that cannot be fully replicated locally.

Best Practices

• Leverage the console-to-IDE transition, local stack integration, and remote debugging features in combination at different stages of the development process.
• Use security best practices, such as restricting remote debugging access to non-production environments.
• Leverage tools like AWS SAM Sync to quickly deploy code changes and start new debugging sessions.
• Take advantage of the ability to debug against event triggers like SQS and API Gateway directly, without the need to send test payloads.

The Serverless Developer Experience Roadmap

• The Lambda roadmap on GitHub provides visibility into upcoming features and allows developers to provide feedback and ideas.
• Continuous improvements to the serverless developer experience are a priority, based on user feedback and evolving needs.