Klayers is a registry of pre-built Lambda layers for common Python runtimes, published as region-specific Amazon Resource Names (ARNs) for direct attachment to serverless functions. The project eliminates per-function build steps by distributing immutable, runtime-versioned library layers as pre-packaged artifacts across AWS regions, enabling dependency injection without any build or compilation step.
The service maintains a curated catalog of layer ARNs indexed by library, runtime, and AWS region, allowing developers to browse available layers and attach them to Lambda functions by referencing a static ARN. Layers are distributed as read-only, versioned artifacts that guarantee consistent dependency snapshots, with a runtime-versioned matrix ensuring compatibility across Python 3.8 through 3.12 and other supported execution environments.
The project covers the full lifecycle of Lambda layer management, from region-specific ARN resolution for cross-region deployment to static pre-build packaging that reduces deployment latency. Documentation provides the complete table of available layer ARNs for direct copy-paste selection.