Send EMAIL via SendGrid API using Shell Script

We had a requirement to send the Emails via SendGrid using a shell script, SendGrid does expose their HTTP API's. Below are some cURL examples for several basic use cases to get you sending email through SendGrid's v3 Mail Send endpoint right away!


Hello, World!

curl --request POST \
  --url https://api.sendgrid.com/v3/mail/send \
  --header 'Authorization: Bearer YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --data '{"personalizations": [{"to": [{"email": "recipient@example.com"}]}],"from": {"email": "sendeexampexample@example.com"},"subject": "Hello, World!","content": [{"type": "text/plain", "value": "Heya!"}]}'

Sending a Basic Email to Multiple Recipients

curl --request POST \
  --url https://api.sendgrid.com/v3/mail/send \
  --header 'authorization: Bearer YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --data '{"personalizations": [{"to": [{"email": "recipient@example.com"}],"cc": [{"email":"recipient2@example.com"}, {"email": "recipient3@example.com"}, {"email":"recipient4@example.com"}]}], "from": {"email": "sendeexampexample@example.com"},"subject":"Hello, World!", "content": [{"type": "text/plain", "value": "Heya!"}]}'

Sending a Basic Email Using a Template

curl --request POST \
  --url https://api.sendgrid.com/v3/mail/send \
  --header 'authorization: Bearer YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --data '{"personalizations": [{"to": [{"email": "recipient@example.com"}]}],"from": {"email": "sendeexampexample@example.com"},"subject":"Hello, World!","content": [{"type": "text/plain","value": "Heya!"}], "template_id" : "YOUR_TEMPLATE_ID"}'

Sending a Basic Email with Attachment

curl --request POST \
  --url https://api.sendgrid.com/v3/mail/send \
  --header 'authorization: Bearer YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --data '{"personalizations": [{"to": [{"email": "recipient@example.com"}]}],"from": {"email": "sender@example.com"},"subject":"Hello, World!","content": [{"type": "text/html","value": "Hey,<br>Please find attachment."}], "attachments": [{"content": "BASE64_ENCODED_CONTENT", "type": "text/plain", "filename": "attachment.txt"}]}'

Sending a Basic Email at a Scheduled Time

curl --request POST \
  --url https://api.sendgrid.com/v3/mail/send \
  --header 'authorization: Bearer YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --data '{"personalizations": [{"to": [{"email": "recipient@example.com"}]}],"from": {"email": "sendeexampexample@example.com"},"subject":"Hello, World!","content": [{"type": "text/plain","value": "Heya!"}], "send_at" : UNIX_TIMESTAMP_HERE}'

Now, Let come to the interesting part, We had to write a script to send multiple attachments to multiple email ids, considering TO, CC and BCC. As you know, Building the JSON for the API Payload using the Shell Script is pretty complex.

Here is the script which you can use...

sh sendEmail.sh 
        -t 'to1@gmail.com;to2@gmail.com' 
        -c 'cc1@gmail.com;cc2@gmail.com' 
        -b 'bcc1@gmail.com;bcc2@gmail.com' 
        -s 'EMAIL SUBJECT' 
        -o 'Email body goes here' 
        -a '/tmp/test.sh;/tmp/test2.sh'