SendGrid Releases Distributed Inbound Email Processing


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One of SendGrid’s core values is getting email to its destination quickly and reliably. Customers also value the ability to get us the email they want delivered, quickly. Very quickly. We have some individual customers sending thousands of messages per second.

Faster Email Sending

SMTP is a great protocol but it is chatty.  It takes many instructions and commands between servers before starting to send the body of an email.  Each of these steps will have to wait for the other server to respond before continuing.

It takes roughly 70-90ms round trip for data going from coast to coast. For a simple SMTP transaction, that can add half a second just to the beginning portion of the conversation. A simplified example:

(90 ms) Connect to port 25
(90 ms) EHLO mail.customer.com
(90 ms) MAIL FROM:<sender@address>
(90 ms) RCPT TO:<receiver@address>
(90 ms) DATA

That’s almost .5 seconds and we didn’t start sending the body of the email yet.

With SendGrid bringing up distributed inbound email locations, we are bringing our servers closer to your servers. Instead of emails taking .5 seconds to start sending the body, they only take .1 seconds. A 5x improvement, depending on the distance. It means faster email sending to SendGrid with fewer resources needed for our customers.

Our Inbound Email Processing Locations

Today, we have five inbound email processing locations:

  • San Jose, CA
  • Washington, D.C.
  • Dallas, TX
  • Singapore
  • Amsterdam

We will be adding several more locations based on the research we have done on where our customers send email. All these locations can also be backups for each other. Traffic will automatically shift for all customers if there is a problem with a specific location and for our high volume customers we can individually move their traffic to specific locations. High volume customers will not need to change any configurations on their side.

In addition, this will allow us to distribute our infrastructure to some of our premium partners. With a distributed architecture, we can place our servers on the same network as our customers hosted through SendGrid’s partner network.

This is just the beginning of distributing SendGrid’s infrastructure globally to better serve our customers and partners. Stay tuned to the blog for more updates.


Jon Prall is the VP of Operations at SendGrid. He is a veteran internet entrepreneur and executive with more than 20 years of management and leadership success behind him.

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