elysia-lambda-response-body-debug

What problem does it solve?

When deploying Elysia.js applications to AWS Lambda with API Gateway proxy integration, users encounter a common but frustrating issue: Lambda returns HTTP 200 status with the correct content-type: application/json header, but the response body is always empty (content-length: 0), with no errors visible in CloudWatch logs. This breaks all API functionality for end users, with no clear error messages to guide debugging.

Core Features & Use Cases

• Targeted Root Cause Diagnosis: Step-by-step local tests to confirm the issue, isolate Elysia's custom Response implementation as the source, and compare arrayBuffer() vs text() behavior to pinpoint the failure point.
• Verified Production Fix: A simple, tested code change to replace response.arrayBuffer() with response.text() in the Lambda handler, eliminating the empty body issue without unnecessary base64 encoding complexity.
• Adjacent AWS Troubleshooting: Guidance for related deployment pitfalls including CDK Lambda permission drift causing 403 AccessDeniedException, API Gateway test-invoke vs real API error code mismatches, and Headers constructor bugs in Lambda Node.js 18 runtimes.
• Real-World Use Case: A developer deploying an Elysia.js REST API to AWS Lambda can use this skill to resolve empty response bodies in minutes instead of spending hours debugging obscure Lambda runtime and AWS configuration quirks.

Quick Start

Use the elysia-lambda-response-body-debug skill to diagnose and fix empty response bodies for your Elysia.js application deployed to AWS Lambda by applying the verified handler code change.