Direct S3 to Lambda vs EventBridge between S3 and Lambda

s3-eventbridge-lambda.md

When should you use direct S3 to Lambda vs an EventBridge in between S3 and Lambda

S3 ==> Lambda 
    vs 
S3 ==> EventBridge ==> Lambda

TL;DR

If your use case is simple and you only need to trigger a Lambda function when a new file is added to an S3 bucket, a direct S3 to Lambda integration is likely sufficient. If you have more complex needs, then introducing EventBridge might be beneficial.

When Direct Integration is Sufficient:

• Single Consumer: If only a Lambda function needs to be triggered.
• Simple Use Case: If you don't require complex routing or event transformation.
• Low Latency: If you need the Lambda function to execute as quickly as possible after the S3 event.
• Cost Sensitivity: If you want to minimize additional costs.

When to Use EventBridge

• Multiple Consumers: If the S3 event needs to trigger multiple services, not just a Lambda.
• Complex Routing: If you need more complex routing than S3’s basic prefix/suffix filtering.
• Event Transformation: If you need to modify the event before it reaches Lambda.
• Event Replay and Archiving: If you need these features for debugging or auditing.