Amazon SES

What is Amazon SES?

Amazon Simple Email Service (SES) is a cloud-based email service designed to help digital marketers and application developers send transactional emails, marketing messages, and other high-quality content. It's a highly scalable and reliable platform that also allows you to receive emails and integrate robustly with other AWS services to build sophisticated email-handling applications.

Key Concepts & Workflow

Understanding the SES workflow is key to using it effectively. It revolves around proving your identity, maintaining a good sender reputation, and choosing the right sending method.

• Identities: Before you can send an email, you must prove to SES that you own the "from" address. This is done by creating and verifying an identity.

• Sandbox Environment: All new SES accounts start in a sandbox. This is a test environment with strict limitations (e.g., can only send to verified identities, low sending volume) designed to prevent fraud and abuse. You must request to move your account out of the sandbox to gain production access.

• Sender Reputation: Your reputation determines whether Internet Service Providers (ISPs) deliver your emails to the inbox, the spam folder, or block them entirely. It is heavily influenced by your bounce rate and complaint rate. Actively managing these is critical for success with SES.

• Configuration Sets: These are sets of rules you can apply to the emails you send. They allow you to publish email sending events—such as deliveries, bounces, complaints, and opens/clicks—to other AWS services like SNS, CloudWatch, or Kinesis Data Firehose for detailed tracking and analysis.

Identity and Verification

You cannot send an email from an address or domain until you verify it.

• Verifying an Email Address:

  • The simplest method, ideal for getting started quickly.

  • SES sends a verification link to the specified email address.

  • Once you click the link, that single email address is authorized for sending. This verification is valid for a specific AWS Region.

• Verifying a Domain:

  • The recommended and more scalable approach.

  • Verifying a domain authorizes you to send from any email address within that domain (e.g., contact@example.com, support@example.com).

  • Process: SES provides you with DNS records (typically CNAME or TXT records) that you must add to your domain's DNS configuration.

  • DKIM (DomainKeys Identified Mail): When you verify a domain, SES guides you to set up DKIM. This is an essential email authentication standard that adds a digital signature to your emails, proving they haven't been tampered with and originated from your authorized domain, which significantly improves deliverability.

Managing Sender Reputation & Deliverability

Maintaining a healthy sender reputation is the most important aspect of using SES. High bounce and complaint rates will lead to warnings and potential suspension of your sending privileges.

• Bounce Rate: The percentage of emails that are permanently rejected (hard bounces) by the recipient's mail server. Your bounce rate should remain below 5%.

• Complaint Rate: The percentage of recipients who report your email as spam. Your complaint rate should remain below 0.1%.

How to Handle Bounces and Complaints

You must have an automated process to stop sending emails to addresses that have bounced or complained. The standard AWS architecture for this is:

1. Configure SES Notifications: Set up a Configuration Set to publish bounce and complaint events to an Amazon SNS topic.

2. Queue the Notifications: Subscribe an Amazon SQS queue to the SNS topic. This adds resilience and ensures notifications are not lost.

3. Process the Queue: Use an AWS Lambda function to read messages from the SQS queue.

4. Update Suppression List: The Lambda function should add the recipient's email address to a suppression list, typically stored in a database like Amazon DynamoDB, preventing you from sending to them again.

Sending Environments: IP Addresses

SES provides different IP address options to match your sending volume and reputation management needs.

• Shared IP Addresses:

  • The default option, best for most customers.

  • You send from a pool of IP addresses shared with other SES users.

  • Cost-effective and easy to use, but your reputation can be influenced by other senders in the pool (though AWS actively manages this).

• Dedicated IP Addresses:

  • IP addresses reserved exclusively for your account. You have complete control over your sending reputation.

  • Ideal for high-volume senders who want to isolate their reputation.

  • Requires an initial "warm-up" period where you gradually increase sending volume to build a positive history with ISPs.

Sending Authorization

This feature allows you to authorize another AWS user or service (a "delegate sender") to send email from one of your verified identities without sharing your AWS credentials.

• How it works: The identity owner attaches a resource-based policy (similar to an IAM policy) to their verified identity. This policy specifies which AWS account is allowed to use the identity and what actions they can perform (e.g., ses:SendEmail).

• Use Case: A company (the identity owner) can authorize a third-party email marketing service (the delegate sender) to send marketing campaigns on their behalf from their verified @company.com domain.

Common Use Cases

• Transactional Emails: Send automated, one-to-one emails triggered by user actions, such as password resets, order confirmations, and shipping notifications.

• Marketing Communications: Distribute newsletters, promotional campaigns, and special offers to large audiences.

• Email-Receiving Applications: Use SES to receive incoming emails, which can then trigger Lambda functions to automatically process attachments, create support tickets, or archive messages in S3.

• Bulk Notifications: Send system status alerts, policy updates, and other announcements to a large number of users at once.