Python FastAPI Tutorial (Part 16): AWS S3 and Boto3 - Moving File Uploads to the Cloud

Corey Schafer
Corey SchaferApr 16, 2026

Why It Matters

Storing uploads in S3 eliminates fragile local storage, enabling scalable, secure, and multi‑instance FastAPI deployments.

Key Takeaways

  • Replace local disk storage with AWS S3 for uploaded images.
  • Install Boto3 and configure AWS credentials for FastAPI integration.
  • Create S3 bucket with public read policy for specific prefix.
  • Define IAM policy granting put/delete permissions only to that bucket.
  • Update image processing to return bytes and upload via Boto3.

Summary

The video walks developers through upgrading a FastAPI blog app’s image handling from local disk storage to Amazon S3, emphasizing why container‑based deployments require durable, external object storage.

It outlines the practical steps: installing the Boto3 SDK, creating an S3 bucket with a globally unique name, disabling default public blocks for a specific "profile‑pics" prefix, and attaching a bucket policy that permits public reads only for that path. An IAM policy is then crafted to grant the application least‑privilege put and delete rights, and an IAM user with access keys is generated for local or non‑AWS hosting.

Key examples include the bucket‑naming constraints (lowercase, no underscores), the JSON policy snippets that restrict actions to the "profile‑pics/*" prefix, and the reminder to store access keys in a .env file that is git‑ignored. The presenter also stresses the importance of cleaning up displayed credentials after the demo.

By moving uploads to S3, the app gains scalability, resilience across container restarts, and cost‑effective storage while maintaining security through scoped policies. This transformation readies the codebase for production deployments on any cloud or VPS environment.

Original Description

In this video, we'll be learning how to make our file storage production-ready by moving uploaded images from local disk into AWS S3. We'll walk through creating an S3 bucket, configuring the bucket policy and IAM permissions, and integrating boto3 into our FastAPI application. We'll also refactor our image processing to separate it from the storage layer and handle boto3's blocking calls properly in our async app. By the end of the video, you'll have a production-ready file storage setup that can scale beyond a single server. Let's get started...
The code from this video can be found here:
Full FastAPI Course:
✅ Support My Channel Through Patreon:
✅ Become a Channel Member:
✅ One-Time Contribution Through PayPal:
✅ Cryptocurrency Donations:
Bitcoin Wallet - 3MPH8oY2EAgbLVy7RBMinwcBntggi7qeG3
Ethereum Wallet - 0x151649418616068fB46C3598083817101d3bCD33
Litecoin Wallet - MPvEBY5fxGkmPQgocfJbxP6EmTo5UUXMot
✅ Corey's Public Amazon Wishlist
✅ Equipment I Use and Books I Recommend:
▶️ You Can Find Me On:
My Website - http://coreyms.com/
#Python #FastAPI

Comments

Want to join the conversation?

Loading comments...