AWS S3 now provides strong read-after-write consistency

Before December 2020, S3 had eventual consistency for overwrite PUTs and DELETEs — meaning you could read stale data immediately after a write. This caught many developers off guard.

Since December 2020, S3 provides strong read-after-write consistency for all operations — PUTs, DELETEs, and LIST operations — at no extra cost.

This means:

• Write an object → immediately readable
• Delete an object → immediately gone from LIST
• Overwrite an object → next GET returns the new version

// This is now safe — no sleep/retry needed after upload
_, err := s3Client.PutObject(ctx, &s3.PutObjectInput{
    Bucket: aws.String("my-bucket"),
    Key:    aws.String("config.json"),
    Body:   bytes.NewReader(data),
})

// This will always return the latest data
result, err := s3Client.GetObject(ctx, &s3.GetObjectInput{
    Bucket: aws.String("my-bucket"),
    Key:    aws.String("config.json"),
})

Old codebases may still have unnecessary retry loops from the eventual consistency era — worth cleaning up.