What are Lambda layers, and when would you use them?

Difficulty: 5/10

code reuse, dependency management, deployment size

Lambda layers are a distribution mechanism for libraries, custom runtimes, and other dependencies that can be used by multiple Lambda functions. They help you avoid duplicating code across functions and keep your deployment packages smaller and more maintainable.

When to Use Lambda Layers

1
Sharing common code or utility functions across multiple Lambda functions
2
Including third-party libraries or frameworks (e.g., requests for Python or axios for Node.js)
3
Packaging custom runtimes or binaries
4
Reducing deployment package size by moving dependencies into a separate layer
5

Creating and Using a Lambda Layer via AWS CLI

Scenario Questions

0-2 years experience

2-5 years experience

1During a sprint you notice that a new version of a shared library breaks one of the functions that uses a layer. Walk me through how you would debug and fix the issue.

Follow-up Questions