Send Email from a WhatsApp Automation

WA.Expert's External API Request step speaks HTTP, not the SMTP protocol. Raw SMTP needs a persistent socket on a port like 587 or 465, which an HTTP request cannot open. The solution: use a transactional email API (MailerSend, SendGrid, or Mailgun). These accept a simple HTTP POST and send the email for you. This guide uses MailerSend as the primary example (free tier: 500 emails/month), with SendGrid and Mailgun in the reference section.

You can only send from a domain you have verified. Sending from noreply@yourcompany.com works once yourcompany.com is verified. Trying to send from a generic address like yourname@gmail.com will fail with a 422 error, because providers block unverified domains to prevent spoofing.

MailerSend Email API: developers.mailersend.com

Body:
{{
  "from": {{
    "email": "noreply@yourcompany.com",
    "name":  "Your Company"
  }},
  "to": [
    {{"email": "{{customer_email}}", "name": "{{customer_name}}"}}
  ],
  "subject": "Thanks for your order, {{customer_name}}!",
  "text":    "Hi {{customer_name}}, we have received your order.",
  "html":    "
Hi {{customer_name}}, we have received your order.
"
}}

Response: HTTP 202 Accepted (empty body)
Header:   X-Message-Id: 5e42957d51f1d94a1070a733

202 means the email was accepted for delivery.
Provide at least one of text or html (both is best).

MailerSend returns HTTP 202 Accepted, not 200, when an email is queued for delivery. The response body is empty; the X-Message-Id response header confirms the send. Branch your flow on the 202 status.

Trigger: Customer completes checkout in a WhatsApp commerce flow.

Captured: {{customer_email}} = priya@example.com
          {{customer_name}}  = Priya Sharma
          {{order_id}}       = ORD-4821
          {{order_total}}    = Rs. 2,499

External API Request step:
POST https://api.mailersend.com/v1/email
Authorization: Bearer YOUR_TOKEN
Content-Type: application/json

Body:
{{
  "from": {{"email": "orders@yourcompany.com", "name": "Your Store"}},
  "to":   [{{"email": "priya@example.com", "name": "Priya Sharma"}}],
  "bcc":  [{{"email": "sales@yourcompany.com"}}],
  "subject": "Order ORD-4821 confirmed — Rs. 2,499",
  "html": "
Hi Priya, your order ORD-4821 is confirmed.
"
}}

Response: HTTP 202, X-Message-Id returned

Result:
  - Priya gets an order confirmation email instantly
  - Your sales team gets a silent bcc copy
  - The WhatsApp bot continues with delivery details

Use the bcc array to send a silent copy to your team. The customer sees only their own address in the to field; your team gets notified without the customer seeing the internal address.

POST https://api.sendgrid.com/v3/mail/send
Authorization: Bearer YOUR_SENDGRID_API_KEY
Content-Type: application/json

Body:
{{
  "personalizations": [
    {{"to": [{{"email": "{{customer_email}}"}}]}}
  ],
  "from": {{"email": "noreply@yourcompany.com"}},
  "subject": "Thanks for your order!",
  "content": [
    {{"type": "text/plain", "value": "Hi {{customer_name}}, ..."}}
  ]
}}

Response: HTTP 202 Accepted
Note: SendGrid wraps recipients in a personalizations array.

POST https://api.mailgun.net/v3/yourcompany.com/messages
Authorization: Basic BASE64('api:YOUR_MAILGUN_API_KEY')
Content-Type: application/x-www-form-urlencoded

Body (form-encoded, not JSON):
  from=noreply@yourcompany.com
  to={{customer_email}}
  subject=Thanks for your order!
  text=Hi {{customer_name}}, we have received your order.

Response: HTTP 200 with a JSON body containing a message id
Note: Mailgun uses Basic Auth (username 'api') and form-encoded
body, not JSON. The domain is in the URL path.

All three work from the External API Request step. MailerSend has the simplest JSON body and a generous free tier, which is why this guide uses it as the default.