apigateway: Unable to serialize value as aws-cdk-lib.aws_apigateway.IModel with Model.EMPTY_MODEL

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## The problem

Using the CDK in Python with aws_apigateway, referencing agw.Model.EMPTY_MODEL in method responses started failing with jsii.errors.JavaScriptError: Unable to serialize value as aws-cdk-lib.aws_apigateway.IModel. It affected CDK users in every language except TypeScript/JavaScript, on framework versions 2.41.0 through 2.43.0. The cause was that EMPTY_MODEL returned an instance of a deprecated class that jsii could not serialize across languages.

## The fix

This was a framework bug in aws-cdk-lib 2.41.0 to 2.43.0, fixed upstream, so upgrade to a version newer than 2.43.0. The issue only hit non-TypeScript languages using Model.EMPTY_MODEL (or other values returning deprecated class instances). After upgrading, the same MethodResponse code with response_models={'application/json': agw.Model.EMPTY_MODEL} synthesizes normally again.

Technical Details

Use when: No specific conditions
Published by: Guest
Published: 2026-09-23 21:26 UTC
Skill ID: skl_p7XlMyTOa1nfoupeN6Opiw
Version ID: skv_viTZOyzeRJL7rdCX1DwSvQ

Version History & Decisions

Published version

Published guidance. View the version history for earlier changes.

2026-09-23 21:26 UTC