title: How to perform AWS S3 multi-part upload without sharing secret keys
body: <p>I am developing an image sharing application in which I have to deal with a huge number of S3 image uploads.Currently, I am using S3 pre-signed URLs to upload images from mobile applications.The problem is that this method doesn't support multipart upload.</p>
  
  <p>So I researched on API gateway and lambda file uploads.Finally, I implemented a solution. Here the problem is that API gateway has a content length limit of 10 MB and lambda can only accept JSON payload of max 6 MB.</p>
  
  <p>I am using nodejs as the backend server. How can I perform S3 multipart uploads from the mobile application without sharing IAM secret keys?</p>
  
  <p>I found another way of signing each multipart URL from the server.But there is no proper guide for implementation.</p>
  
  <p>Can somebody give a proper answer?</p>
  
  <p>NB: I don't want to give public write access to S3 bucket and I am not using EC2 servers.</p>