File From Api Gateway: Download |verified|

If your file is small (under 10MB due to API Gateway’s payload limit) and you need to perform logic before the download—like verifying a subscription—this is the most flexible route.

You must Base64-encode the file content in the Lambda response and set isBase64Encoded: true .

Depending on your file size and security needs, there are three primary ways to implement this: 1. The Standard Lambda Proxy (Small Files < 10MB) download file from api gateway

Your API triggers a Lambda function that fetches the file from storage (like S3).

Downloading a file from an API Gateway is a common requirement for modern applications, whether you're serving generated reports, user-uploaded images, or software packages. While API gateways are primarily designed for lightweight JSON data, they offer robust features for handling larger binary files. If your file is small (under 10MB due

For a more performant approach that skips Lambda execution costs, you can configure API Gateway to act as a direct proxy for Amazon S3.

You must go to your API's Settings and add the specific MIME type (e.g., application/pdf ) or use a wildcard */* under Binary Media Types . This tells the gateway not to corrupt the binary data by treating it as text. Pros: Lower latency and cost since no code is executed. The Standard Lambda Proxy (Small Files Your API

Use the Content-Disposition header set to attachment; filename="yourfile.ext" to force the browser to download the file rather than display it. 2. Direct S3 Proxy (Medium Files & Static Assets)