A manual weekly SNS campaign was replaced by a scheduled EventBridge trigger in two CloudFormation templates: an Events rule in UTC and a Scheduler in local time.

Every Friday around 11 PM, someone on the marketing team of a retail client opened the Amazon SNS console, pasted the Saturday campaign copy into the message field and clicked publish. The topic carried a few million confirmed subscriptions, in a mix of email, SMS, mobile push and one SQS queue feeding an internal consumer. The procedure lived in a shared document, with the topic ARN in bold and an all-caps warning to confirm the region before publishing.

What brought me in was not a push for automation. It was an incident. On two consecutive Saturdays the campaign went out twice. The first time, the person published, the page stopped responding, and she published again. The second time, two people each assumed the other was on vacation.…