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SMTP: Servers and Sending Emails

Emails play an enormous function in how we talk, however what occurs once we ship an email? 

The means of sending an email is just like mailing a bodily letter: by a sequence of steps, an organized system takes care of the envelope and drops it off to the recipient. However, with emails, the SMTP server acts just like the submit service—although that’s just the start. 

If you’re simply dipping your toe into the how-email-gets-sent world, it’s straightforward to really feel overwhelmed. To enable you to navigate your email sending—utilizing an SMTP server to ship email—we’ve put collectively a listing of the most typical SMTP server questions we obtain, so that you’ll be an SMTP knowledgeable very quickly. 

What does SMTP stand for?

Curious concerning the SMTP which means? We’re glad you requested. The Simple Mail Transfer Protocol (SMTP) is an software utilized by mail servers to ship, obtain, and relay outgoing email between senders and receivers.

As the expertise behind email communication, SMTP is the protocol that permits you to ship and obtain emails. Without it, email communication could be nonexistent since SMTP determines which servers will obtain your relay messages. 

What is an email server—and what’s an SMTP server?

A mail server is a generalized time period to explain a system that collects, processes, and serves email. Much like a mail service, each email message passes by the mail server earlier than reaching its vacation spot. Without servers, you’ll solely be capable of ship emails to folks whose addresses matched your area— to, as an illustration.  

Because an SMTP email server pertains to outgoing email, it’ll have an tackle (or addresses) that the mail shopper or software you employ can set that usually appears like this: For instance, the SMTP server Gmail makes use of is, and Twilio SendGrid’s is You can usually discover your SMTP email server tackle within the account or settings part of your mail shopper. 

Using a retailer and ahead course of, SMTP works with the mail switch agent to maneuver your email throughout networks to the proper laptop and email inbox.

So when you ship an email with SMTP host Gmail or AOL, the SMTP server processes your email, decides which server to ship the message to and relays the message to that email server. The recipient’s inbox service supplier, similar to Gmail or AOL, then downloads the message and locations it within the recipient’s inbox.

You can discover extra particulars that will help you perceive the SMTP which means on our docs web page.

Common SMTP server suppliers and settings

SMTP Provider URL SMTP Settings
AT&T att.web smtp.mail.att.web
Comcast comcast.web

Is an SMTP server the identical as a standard server?

Like most servers, the SMTP server processes knowledge despatched to one other server, however it has the precise objective of processing knowledge associated to the sending and relaying of email. An SMTP server additionally isn’t essentially on a machine however will be an software always working in anticipation of sending new mail.

Why are SMTP servers essential?

When speaking over email, it’s essential to ship email to your recipient safely and on time. However, without an SMTP server, your email can’t make it to its vacation spot. 

Once you hit Send, the email transforms right into a string of code despatched to the SMTP server, which processes that code to cross the message. Without the SMTP server to course of the message, the message wouldn’t translate. 

Additionally, the SMTP server verifies that the outgoing email is from an lively account. In different phrases, the email server checks whether or not an lively or working email account despatched the outgoing message, defending your inbox from illegitimate email. 

If the email is undeliverable, the SMTP ensures the email will bounce again to the sender, letting them know they’ve an incorrect email tackle or the receiving email server blocked the email for no matter cause. 

Want extra info on SMTP? Check out our SMTP Service Crash Course.

How the Twilio SendGrid SMTP server works

What does the SMTP server do once I ship an email with Twilio SendGrid?

  1. Your mail shopper connects to the SendGrid SMTP server, smtp.sendgrid.web, utilizing port 25 (by default). 
  2. Your mail shopper has a dialog with our server, first verifying that the username and password used for authentication correspond to an lively account, then relaying the message info, similar to sender tackle, recipient, and message content material.
  3. Our server takes the message info we gathered out of your request, then repeats the dialog course of in step 2 with the recipient’s mail server.
  4. Your recipient’s mail server checks the sending tackle, recipient tackle (to make sure it’s a sound recipient), and message content material. It additionally checks the sending area for any potential DNS points, similar to invalid DomainKeys Identified Mail (DKIM) and Sender Policy Framework (SPF) signatures. As lengthy as there are not any points, the recipient’s mail server will use the protocols POP3 or IMAP to retrieve the email and ship the message to its supposed recipient.

Take a have a look at the diagram under for a visible of the SMTP email supply course of.

Does Twilio SendGrid have a take a look at SMTP server?

SendGrid presents free accounts that you possibly can allow with no bank card. With a free SendGrid account, we offer you entry to the SendGrid SMTP server and can help you ship as much as 100 emails per day—successfully giving you an SMTP server for testing. 

Active free account clients also can use their account to ship take a look at messages and take a look at their email deliverability earlier than upgrading and sending considerably extra email.

Do I have to arrange the Twilio SendGrid SMTP server earlier than sending an email?

All you want is an lively SendGrid account and the flexibility to make use of primary username and password authentication inside your email shopper or software to ship an email utilizing our SMTP server.

What SMTP server port do I would like to connect with?

We help unencrypted and TLS encryption on ports 25, 587, and 2525. If you’d prefer to implement SSL encryption, use port 465. 

Send an SMTP email with Twilio SendGrid

Ready to ship an SMTP email? Twilio SendGrid has you coated. 

Check out our documentation to be taught the way to ship an SMTP email. Then, when you join a free account, we’ll stroll you thru the method and share assets that will help you get began.

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