AWS Lambda Runtime Interface Client for NodeJS v4.0.0

Key Changes

Core Architecture:

• Migrated to TypeScript with ESM-first environment
• Targets Node.js 22+ exclusively
• Implements two-dimensional multi-concurrency model for Lambda Managed Instance (Multiconcurrency) compatibility
• Replaced Make/shell scripts with npm-based build system

Handler & Context Updates:

• Removed callback-based handler support (promise-based only)
• Eliminated legacy context.succeed/fail/done methods
• Removed legacy callbackWaitsForEmptyEventLoop getters/setters

Developer Experience:

• Native RIE testing support with single build command
• Introduced InvokeStore package for trace ID propagation via AsyncLocalStorage

Runtime Behavior:

• No BeforeExit event loop waiting (pure runtime loop)
• Worker thread count defaults to logical CPU count
• Configurable via AWS_LAMBDA_NODEJS_WORKER_COUNT

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Read More:

• https://aws.amazon.com/blogs/compute/node-js-24-runtime-now-available-in-aws-lambda/
• https://aws.amazon.com/blogs/aws/introducing-aws-lambda-managed-instances-serverless-simplicity-with-ec2-flexibility/

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Change Log

• Deleting integration tests by @fabisev in #143
• Merge pull request #143 from aws/fabisev/integration-test-deletion by @fabisev in #147
• Bump actions/checkout from 4 to 5 by @dependabot[bot] in #146
• Adding warning callback handlers and isAsync detection by @fabisev in #144
• Update copyright header by @fabisev in #148
• Fix security vulnerabilities in dependencies by @rarepolz in #157
• feat: Prepare for Node.js 24 + Lambda Managed Instances RIC Launch by @godcrampy in #161
• minor: Update contents of packaged artifact + run npm audit fix by @godcrampy in #169

New Contributors

• @rarepolz made their first contribution in #157

Full Changelog: v3.3.0...v4.0.0