How to Handle Heavy Uploads in Backend? | Best Approach

Upload Files Directly from Front-end to Storage Service

Sandeep Singh (Full Stack Dev.)
3 min readMar 11, 2024

When our app has to deal with heavy file uploads(ex: 2GB, 3GB, 15GB , 30GB/File) with millions of users simultaneously, then we can’t just rely on our server. We need a good approach for handling this demand.

What if I tell you, that we can make files upload directly from the client to third party service like AWS S3 !

Yes! its possible, what you may ask what about authentication? our whole authentication logic is there on the server right?

you will get to know everything in the below video. PLease make sure to watch the video to get complete clarity about handling heavy uploads in backend.

This article and video is all about “How to Handle Heavy Uploads in Backend”, a really amazing approach.

Problem Statement:

When dealing with heavy uploads in a backend system, several challenges arise:

  1. Scalability: Traditional server-based solutions may struggle to handle concurrent uploads of large files, leading to performance issues and potential downtime.
  2. Reliability: Large file uploads are prone to failures due to network issues or server crashes, risking data integrity and user experience.
  3. Storage Management: Storing large files on local servers can quickly exhaust storage capacity and require frequent maintenance and upgrades.

Why AWS S3?

AWS S3 offers several advantages that make it an ideal solution for handling heavy uploads:

  1. Scalability: AWS S3 is designed to handle massive amounts of data and can scale automatically to accommodate fluctuating upload traffic.
  2. Durability: Data uploaded to AWS S3 is stored redundantly across multiple data centers, ensuring high durability and availability.
  3. Cost-effectiveness: AWS S3 offers a pay-as-you-go pricing model, allowing businesses to only pay for the storage and bandwidth they use, making it cost-effective for managing heavy uploads.
  4. Security: AWS S3 provides robust security features, including encryption options and access control policies, to protect uploaded data from unauthorized access.

System Design:

To enable direct file uploads to AWS S3 from the frontend, the system architecture can be designed as follows:

  1. Client-Side Upload: When a user initiates a file upload from the frontend, the client-side application needs a pre-signed URL to upload on AWS S3 buckets.
  2. Pre-signed URL Generation: The client-side application sends a request to the backend server, which generates a pre-signed URL using AWS IAM credentials and the AWS SDK.
  3. Pre-signed URL Response: The backend server responds to the client-side application with the pre-signed URL, which includes a time-limited token for uploading a specific file to a designated AWS S3 bucket.
  4. Direct Upload to S3: The client-side application uses the pre-signed URL to upload the file directly to AWS S3 using HTTP PUT or POST requests, bypassing the backend server entirely.
  5. Confirmation and Error Handling: Once the upload is complete, AWS S3 returns a success response to the client-side application. In case of errors, appropriate error handling mechanisms are implemented to retry the upload or notify the user.


Designing a system for handling heavy uploads with AWS S3 involves leveraging its scalability, reliability, and cost-effectiveness. By enabling direct file uploads from the frontend to AWS S3 using pre-signed URLs, businesses can efficiently manage large file uploads while ensuring data security and user experience.



Sandeep Singh (Full Stack Dev.)

Fullstack Developer | MERN & Flutter | Passionate about Open Source | Engaged in Contributing & Collaborating for a Better Tech Community. 🚀