To send email using Google Mail you will have to modify your outgoing server settings in the Mail Settings accordingly. This article will walk you through how to add an SMTP server to an Google Apps account, but you can also follow these steps to add an SMTP server to a general GMail account.

Adding SMTP Settings

Please note: Google applies the following limits:

Limit type Description Value
Messages per day Daily sending limit* 2000
Messages auto-forwarded Messages automatically forwarded from another account; not included in the daily sending limit 10,000
Auto-forward mail filters Account filters that automatically forward mail 20
Recipients per message Addresses in the To, Cc, and Bcc fields of a single email* 2000 (500 external)
Recipients per message (sent via SMTP by POP/IMAP users) Addresses in the To, Cc, and Bcc fields of a single email* 100
Total recipients per day Individual addresses count in every mail sent; 5 emails sent to 10 addresses count as 50 recipients* 10,000
External recipients per day Email addresses outside your primary domain. Includes domain aliases and alternate domains. 3000
Unique recipients per day Individual addresses count once a day; 5 emails sent to 10 addresses count as 10 unique recipients* 3000 (2000 external)

For more detailed information regarding Google’s limits, please visit their Google’s Sending Limits page.

Enabling External SMTP Servers

If you’re using Google Apps, you have to enable your account to send to an external SMTP server. These settings are located on this page: https://www.google.com/a/cpanel/yourdomain/ServiceSettings#ServiceSettings/service=Email

  • If you want all the outgoing mail from your domain to go through SendGrid, add smtp.sendgrid.net to the Outbound gateway setting field. If you choose to do this, this is the only step, and you’re done!
  • If you only want to send some email through SendGrid, check the box in the Outbound relay setting.

Where to set google apps to allow external smtp settings. Outbound gateway forces all email through an external SMTP server. Outbound relay allows a user to set up an alternate SMTP server.

For the purposes of this guide, we will assume the Outbound relay setting was checked, and the Outbound gateway was left blank.

Adding an Alias

If you’re a GMail user, begin here.

Once the Outbound relay setting has been turned on, you need to go to the account you want to send from, and go to Mail Settings > Accounts, and select “Add another email address you own”.
Here, you will put in the address you wish to be sending from. Please note: though you will not log into this account once you’re set up, it does need to be a valid address, so that you can receive the verification code.
You can also specify the reply-to address here. If you do not, any replies to messages sent under this alias will go to the alias’ account.
Please click the image to view in full.
Where to add another send-from address in google accounts

The next step will ask you whether you want to use your default SMTP settings, or the other domain. Select the other domain (second radio button), and put in the following details:

  • SMTP Server: smtp.sendgrid.net
  • Port: Leave this option to the default of 587.
  • Username: SendGrid account username
  • Password: SendGrid account password
  • Encryption: Either option is acceptable.

Google's screen to specify external SMTP server settings.

Sending as the Alias

As you’re sending a message, you should now see a From: field as a dropdown. If you select the Alias you’ve set up with the SendGrid SMTP, it will be sent through our servers, with all apps applied as needed.
Choosing which account to send as.

Unfortunately, it is not possible to add SMTP API headers to the message in Google Mail. We suggest Thunderbird if you want that level of control.