Compatibility

This page separates package metadata, CI coverage, and AWS Lambda runtime aliases. A pyproject.toml classifier describes what a package advertises; it does not prove that a workflow executes that version. A runtime alias selects an AWS CDK Runtime for a generated Lambda; it is not the Python version used to run the package's tests or the version required to install the package.

Python packages

Package	Minimum Python to install and run the package	Classifiers in pyproject.toml	Python versions executed by CI
lambda-api-decorators	>=3.9	3.9, 3.10, 3.11, 3.12, 3.13, 3.14	3.9, 3.10, 3.11, 3.12, 3.13, 3.14
lambda-api-decorators-cdk	>=3.10	3.10, 3.11, 3.12, 3.13, 3.14	3.10, 3.11, 3.12, 3.13, 3.14

The first package is CDK-free and contains decorators and runtime helpers. The second consumes those declarations and imports AWS CDK. The minimum versions come from each package's requires-python; the classifier and CI columns are reported separately because neither one changes the installation requirement.

These packages are used in different dependency scopes. Install lambda-api-decorators-cdk in the CDK application that synthesizes the stack, and install lambda-api-decorators in the Lambda source dependencies that CDK packages for deployment. They do not need to be installed together in the same environment: the first is infrastructure-side and the second is runtime-side. The Getting Started dependency example shows this split.

Lambda runtimes

The CDK builder registers these aliases and maps each one to the corresponding AWS CDK Python runtime:

Alias recognized by @runtime and the builder	What it means
python3.10, python3.11, python3.12, python3.13, python3.14	A lookup key for the matching aws_lambda.Runtime value when configuring a generated Lambda.

These aliases are builder behavior, not the package compatibility promise. A Lambda runtime is selected through LambdaApiConfig(default_runtime="alias") or a @runtime("alias") declaration; the decorator overrides the default. See the Lambda configuration guide and the runtime API reference.

AWS CDK, Node.js, CLI, and Docker

Concern	Verified current behavior
AWS CDK	The CDK package targets AWS CDK v2. Its package dependency is the unpinned aws-cdk.aws-lambda-python-alpha; the runnable examples declare aws-cdk-lib>=2.0.0,<3.0.0 and constructs>=10.0.0,<11.0.0. No narrower CDK version range is declared by the package itself.
AWS CDK CLI	The examples require the AWS CDK CLI for cdk synth, cdk bootstrap, cdk deploy, and cdk destroy.
Node.js	The documentation site declares Node.js >=20.0 in its own package.json. The Python packages and examples do not declare a Node.js version. AWS CDK CLI installation may add its own Node.js requirement.
Docker	The examples and their infrastructure tests require Docker because CDK's PythonFunction bundles Lambda source in a container.

The CDK package uses AWS CDK as its current infrastructure backend. The examples are the source of the stated aws-cdk-lib and constructs ranges; they are not a promise that every future CDK v2 release has been tested.

REST and HTTP APIs

Capability	REST API	HTTP API
Construct created by LambdaApi when selected	aws_apigateway.RestApi	aws_apigatewayv2.HttpApi
Route decorators discovered from Python source	GET, POST, PUT, DELETE, ANY	GET, POST, PUT, DELETE in the current end-to-end path
Additional mappings in the low-level HTTP route table	N/A	CDK mappings exist for PATCH, OPTIONS, and HEAD, but the AST discovery layer does not recognize those decorator names, so they are not currently usable as discovered routes
Existing API support	Created or imported REST API objects with the supported REST interface	Concrete aws_apigatewayv2.HttpApi objects; imported HTTP interface objects are currently rejected by the concrete type check

ANY is part of the public decorator API and is emitted by the REST builder. It has no HTTP mapping and therefore cannot be used with an HTTP LambdaApi. The complete route behavior is documented in REST and HTTP APIs, and API reuse is covered by Using an existing API.