Making S3 Buckets Talk Back with Event Notifications

One day, I uploaded a file into my S3 bucket and thought: “Wouldn’t it be cool if something happened automatically when I drop a file here?”
Turns out, AWS already thought of this: S3 Event Notifications.

🔔 What are S3 Event Notifications?

They’re like little messengers. Whenever something happens inside your bucket—like a new file upload, delete, or update—S3 can notify other AWS services instantly.

For example:

• Upload a file → Trigger Lambda function.

• Delete an object → Send a message to SNS topic.

• Put new images → Queue them in SQS for later processing.

⚙️ How I Set It Up

Here’s what I did with my project:

1. In my S3 bucket, I went to the Properties tab → Event notifications → Create event notification.

2. Gave it a name: image-upload-trigger.

3. Event type: PUT (Object Created).

4. Prefix filter: images/ (only for files uploaded in the images folder).

5. Destination: Lambda function that resizes images automatically.

Now, whenever I upload an image, Lambda resizes it—like magic.

🌟 Why I Love This

• Automation → No manual processing.

• Integration → Works seamlessly with Lambda, SNS, SQS.

• Real-time reactions → My bucket feels “alive.”