Monthly Cost Digest Lambda

Monthly Cost Digest Lambda

A monthly email with your AWS cost breakdown by service, region, and tag — delivered on the first of every month without any manual effort. This CloudFormation stack deploys a Lambda function triggered by EventBridge that pulls Cost Explorer data and sends a clean, formatted digest via SES.

What Is Included

A CloudFormation template that wires up a Lambda function, an EventBridge rule (1st of month, configurable time), and the IAM role with least-privilege Cost Explorer and SES permissions. The Lambda queries the prior month costs, groups by service and region, filters by your configured cost allocation tags, and sends a formatted HTML email.

Developer Experience

• One deploy, zero maintenance — runs itself every month
• Configurable: recipient list, tag filter, and cost threshold for alerting
• HTML email with cost table sorted by spend
• No external dependencies in the Lambda — pure boto3

What You Get

• monthly-digest.yaml — CloudFormation template
• lambda/handler.py — Lambda function source
• deploy.sh
• .env.example
• README.md

Requirements

AWS account, Cost Explorer enabled, SES configured (verified sender domain or email), permissions to deploy CloudFormation (Lambda, EventBridge, IAM). SES sandbox mode requires verified recipient addresses.