Handling large file uploads in modern web applications often poses a significant challenge, especially when scalability and performance are crucial. This is even more complex when the backend involves serverless computing, such as AWS Lambda. Lambda functions are not designed to handle large payloads directly due to resource constraints, but with the right techniques, you can build an efficient file upload system that interacts seamlessly with AWS services like S3. In this guide, I’ll walk you through a structured approach to uploading large files from a front-end application to an AWS Lambda function built using Java 17, which then uploads the file to Amazon S3. We’ll explore not only the code, but also the practicalities, tips, and considerations to ensure your implementation is smooth and efficient.