2025 · Platform
A secure presigned URL service for direct-to-S3 uploads
an enterprise client needing secure file upload infrastructure · Cloud/backend engineer
The problem
Backend services needed to store and fetch files in cloud storage. Giving each service its own access key does not scale, and sending files through a server wastes compute.
What I built
I built a small service that issues short-lived, signed links for uploads and downloads, with sign-in and permissions per caller.
The result
Services no longer needed their own access keys, and every transfer could be traced to a caller.
Main tools
- AWS Lambda
- API Gateway
- Amazon S3
- Amazon Cognito
- CloudFront
This is the short version. The full case study is available on request.