Send mail through SendGrid Web API using PowerShell

I found the SendGrid API documentation is lacking an simple PowerShell example to use their API, so here it is: Use Twilio SendGrid Web API v3 endpoints, including the new v3 /mail/send to send mail using PowerShell.

Why use the API over SMTP? Using the SendGrid API is more secure than traditional SMTP, avoids port blocking issues in cloud environments, and provides better delivery analytics. If you are looking for the traditional SMTP method for internal servers, see my basic PowerShell email guide here.

Learn how to use the Twilio SendGrid Web API v3 to send mail with PowerShell without additional modules.

# fill in your API key
$apikey = ''

$headers = @{
  Authorization="Bearer ${apikey}"
}

$bodyParams = @'
  {
    "personalizations": [
      {
        "to": [
          {
            "email": "recipient@example.net",
            "name": "Firstname Lastname"
          }
        ],
        "subject": "Hello, World!"
      }
    ],
    "content": [
      {
        "type": "text/plain",
        "value": "Heya!"
      }
    ],
    "from": {
      "email": "sender@example.com",
      "name": "Firstname Lastname"
    },
    "reply_to": {
      "email": "sender@example.net",
      "name": "First Name"
    }
  }
'@

Invoke-RestMethod -Method POST `
  -Uri https://api.sendgrid.com/v3/mail/send `
  -Headers $headers `
  -ContentType 'application/json' `
  -Body $bodyParams

This is it.

Configurable Sending in the EU

This feature empowers you to send outbound emails directly from servers located within the European Union, ensuring compliance with GDPR regulations and enhancing data privacy. If you need to use the EU region, verify your API key is valid and change the URI to api.eu.sendgrid.com.

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Quick guide: SMTP vs. API

Feature	Standard SMTP (Send-MailMessage)	SendGrid API (REST)
Best For	Internal servers, Exchange, local relays.	Azure/AWS, Cloud apps, High-volume.
Common Ports	587 (StartTLS) or 465 (SSL).	443 (HTTPS).
Cloud Status	Port 25 is almost always blocked.	Fully supported in all cloud environments.
Security	Basic Auth / IP Whitelisting.	Secure API Keys / Bearer Tokens.
Analytics	Minimal (Server logs only).	Full (Opens, clicks, bounces).

When configuring SMTP, aim for Port 587 with StartTLS as it is the modern standard for secure mail submission. If you are unsure if your server supports it, you can manually test SMTP authentication and StartTLS via telnet or OpenSSL first. Avoid Port 25 for anything other than internal relays, as most modern cloud providers (Azure/AWS) block it by default to prevent spam.

Conclusion

Twilio SendGrid is a company having their security options in place for secure mail sending. With security options you have to think about SPF, DNSSEC, StartTLS, encryption, authentication and account protection features. These include opportunistic TLS, enforced TLS, DKIM, SPF, DMARC, API keys with granular permissions, two-factor authentication, and IP Access Management.

Being able to send an email through SendGrid, using either PowerShell or .NET, can come in handy when sending DevOps reporting mails. This is a nice addition to my Send email with PowerShell post, but without additional modules.