AWS Ses Inbound

Skill Contract

Purpose

• Configure SES inbound email reception with SNS webhook delivery.

Inputs

• AWS credentials, verified domain, and HTTPS webhook endpoint.

Outputs

• Active receipt rule set and confirmed SNS subscription.

Completion Signals

• complete when the rule set is active and SNS shows confirmed subscription.
• continue when awaiting DNS verification or subscription confirmation.
• error on permission failures or invalid credentials.

Credential Missing Behavior

• If AWS credentials are missing, ask the user and stop.

What I Do

Set up Amazon SES (Simple Email Service) for receiving inbound emails and forwarding them to a webhook via SNS (Simple Notification Service). This is commonly used for:

• AI email agents that process incoming emails
• Email-to-ticket systems
• Inbound email parsing APIs

Prerequisites

• AWS CLI installed: brew install awscli or pip install awscli
• AWS credentials with SES and SNS permissions
• Domain with configurable DNS (for MX records)

Credential Setup

Set credentials via environment variables:

export AWS_ACCESS_KEY_ID='AKIA...'
export AWS_SECRET_ACCESS_KEY='...'
export AWS_DEFAULT_REGION='us-east-1'

Or use AWS CLI profile:

aws configure --profile ses-admin
export AWS_PROFILE=ses-admin

Supported Regions for SES Inbound

SES inbound email is only available in:

• us-east-1 (N. Virginia)
• us-west-2 (Oregon)
• eu-west-1 (Ireland)

Complete Setup Flow

Step 1: Verify Domain in SES

# Register domain for verification
aws ses verify-domain-identity --domain example.com

# Response includes VerificationToken - add as TXT record:
# Name: _amazonses.example.com
# Value: <VerificationToken>

Step 2: Get DKIM Tokens

# Get DKIM tokens for email authentication
aws ses verify-domain-dkim --domain example.com

# Response includes 3 DkimTokens - add as CNAME records:
# Name: <token>._domainkey.example.com
# Value: <token>.dkim.amazonses.com

Step 3: Create SNS Topic

# Create topic for receiving email notifications
aws sns create-topic --name my-inbound-email-topic

# Save the TopicArn from response

Step 4: Create SES Receipt Rule Set

# Create a rule set (container for rules)
aws ses create-receipt-rule-set --rule-set-name my-email-rules

Step 5: Create Receipt Rule

# Create rule to forward emails to SNS
aws ses create-receipt-rule \
  --rule-set-name my-email-rules \
  --rule '{
    "Name": "forward-to-sns",
    "Enabled": true,
    "Recipients": ["example.com"],
    "Actions": [
      {
        "SNSAction": {
          "TopicArn": "arn:aws:sns:us-east-1:123456789:my-inbound-email-topic",
          "Encoding": "UTF-8"
        }
      }
    ],
    "ScanEnabled": true
  }'

Step 6: Activate Rule Set

# Only one rule set can be active at a time
aws ses set-active-receipt-rule-set --rule-set-name my-email-rules

Step 7: Subscribe Webhook to SNS

# Subscribe your HTTPS endpoint to the SNS topic
# IMPORTANT: Use --notification-endpoint, NOT --endpoint
# (--endpoint overrides the AWS API URL, which is NOT what you want)
aws sns subscribe \
  --topic-arn "arn:aws:sns:us-east-1:123456789:my-inbound-email-topic" \
  --protocol https \
  --notification-endpoint "https://example.com/api/email-webhook"

Important: Your webhook endpoint must handle the SNS subscription confirmation request. SNS sends a POST with:

• Header: x-amz-sns-message-type: SubscriptionConfirmation
• Body: JSON with Type, SubscribeURL, Token, etc.

Your endpoint must visit the SubscribeURL (make a GET request) to confirm the subscription.

Required DNS Records

After running the SES commands, add these DNS records:

Domain Verification (TXT)

Name: _amazonses.example.com
Type: TXT
Value: <VerificationToken from verify-domain-identity>

DKIM Records (3 CNAMEs)

Name: <token1>._domainkey.example.com
Type: CNAME
Value: <token1>.dkim.amazonses.com

Name: <token2>._domainkey.example.com
Type: CNAME
Value: <token2>.dkim.amazonses.com

Name: <token3>._domainkey.example.com
Type: CNAME
Value: <token3>.dkim.amazonses.com

MX Record (for receiving email)

Name: example.com (or subdomain like mail.example.com)
Type: MX
Priority: 10
Value: inbound-smtp.<region>.amazonaws.com

For us-east-1: inbound-smtp.us-east-1.amazonaws.com

Checking Status

Verify Domain Status

aws ses get-identity-verification-attributes --identities example.com
# VerificationStatus should be "Success"

Check DKIM Status

aws ses get-identity-dkim-attributes --identities example.com
# DkimVerificationStatus should be "Success"

List Receipt Rules

aws ses describe-active-receipt-rule-set
aws ses describe-receipt-rule --rule-set-name my-email-rules --rule-name forward-to-sns

List SNS Subscriptions

aws sns list-subscriptions-by-topic --topic-arn "arn:aws:sns:..."
# SubscriptionArn should show confirmed ARN, not "PendingConfirmation"

Webhook Payload Format

SNS sends JSON with this structure:

{
  "Type": "Notification",
  "MessageId": "...",
  "TopicArn": "arn:aws:sns:...",
  "Message": "{\"notificationType\":\"Received\",\"content\":\"<raw MIME email>\",...}",
  "Timestamp": "...",
  "Signature": "...",
  "SigningCertURL": "..."
}

The Message field contains a JSON string with:

• notificationType: "Received" for incoming emails
• content: Raw MIME email content (needs parsing)
• mail: Metadata (messageId, source, destination, headers)

Use a library like mailparser (Node.js) or email (Python) to parse the MIME content.

SNS Subscription Confirmation

When you first subscribe, SNS sends a confirmation request:

{
  "Type": "SubscriptionConfirmation",
  "SubscribeURL": "https://sns.us-east-1.amazonaws.com/?Action=ConfirmSubscription&...",
  "Token": "...",
  "TopicArn": "..."
}

Your webhook must:

1. Detect Type === "SubscriptionConfirmation"
2. Make a GET request to the SubscribeURL
3. Return 200 OK

Signature Verification

Always verify SNS message signatures in production:

1. Validate SigningCertURL is from *.amazonaws.com
2. Fetch the certificate
3. Build the canonical message string
4. Verify signature using the certificate's public key

Troubleshooting

"Domain not verified"

• Check TXT record: dig _amazonses.example.com TXT
• DNS propagation can take up to 72 hours (usually 5-30 min)

"DKIM not verified"

• Check CNAME records: dig <token>._domainkey.example.com CNAME
• Ensure all 3 DKIM records are added

Emails not arriving

• Verify MX record points to correct SES inbound server
• Check receipt rule set is active
• Verify recipient domain/address matches rule

Webhook not receiving

• Check SNS subscription status (should not be "PendingConfirmation")
• Verify endpoint is publicly accessible via HTTPS
• Check endpoint handles SNS confirmation handshake
• Review CloudWatch logs for SNS delivery failures

"Access Denied" errors

• Verify IAM user has AmazonSESFullAccess and AmazonSNSFullAccess policies
• Check region is correct (SES inbound only in us-east-1, us-west-2, eu-west-1)