Ravi Sir's Cards › AWS
How do you avoid double receipt emails?
What is a VPC: your own private network inside one AWS Region, example ThreeTierVpc 10.0.0.0/16.
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What this card says
What it is
S3 may deliver the same event more than once; handlers must be idempotent.
Why it matters
Key receipts by object etag/versionId; skip SendEmail if the row exists.
How / example
PutItem ConditionExpression attribute_not_exists(receiptId) before SES.