We believed Amazon SES could help us be elastic, that we could pay as we went along, and that we could stop worrying about optimizing settings for each ISP.
Devika Chawla Director of Messaging and Platform Engineering, Netflix

Online content provider Netflix keeps in contact with over 100 million customers in 190 countries using Amazon Simple Email Service (Amazon SES). Netflix has achieved very high inbox placement rates while delivering hundreds of millions of emails every day.  

Before migrating to Amazon SES, Netflix maintained an in-house solution for sending email. This solution carried its own operational overheads including running dedicated servers with email delivery software, optimizing email sending practices for each Internet Service Provider (ISP) etc. Scaling this setup dynamically in new regions was not easy, because it required replicating this setup in data centers co-located in each new region. This solution created a single point of failure for email delivery.

Another challenge had to do with Netflix's diverse email portfolio; it included transactional messages (such as account information and password reset emails), product messages for current customers (including personalized recommendations and new features), and marketing messages for potential and former customers. Each type of email sent to each of these customer segments came with its own level of importance, as well as its own potential risks to Netflix's reputation as an email sender.  

Netflix needed an email solution that was flexible and affordable, that was highly scalable, that had global reach, and that promised excellent deliverability. "We believed Amazon SES could help us be elastic, that we could pay as we went along, and that we could stop worrying about optimizing settings for each ISP, and so we embarked upon a plan to test and migrate to Amazon SES," said Devika Chawla, Director of Engineering for Netflix's Messaging and Platform team.  

Netflix began by creating pools of dedicated IP addresses. Each of these pools was dedicated to sending a particular type of email. For example, transactional messages sent to existing customers (which carry a very low risk of being reported as unsolicited email) were sent from one pool of IP addresses, while marketing messages sent to potential or former customers (which carry a higher risk of being reported) were sent from another. By creating these dedicated IP pools, Netflix was able to isolate the reputations of different pools of IP addresses, thereby maximizing the delivery of its most critical communications.

Netflix then started routing small amounts of outbound email to Amazon SES, in order to help ISPs understand the type and volume of email they would be receiving from Netflix's dedicated IP addresses. After sending these messages, Netflix then evaluated the impact that sending from Amazon SES had on its bounce and complaint rates, its sender reputation, and its inbox placement rates. Once Netflix was satisfied that these metrics were within acceptable rates, they gradually started sending more and more email through Amazon SES. After repeating this send-and-evaluate process numerous times, Netflix was able to migrate its email sending activities to Amazon SES.  

To evaluate the effectiveness of using Amazon SES to deliver its marketing and transactional emails, Netflix worked with a third-party to gauge its inbox placement rates and sender reputation scores. The results of these analyses showed inbox placement rates exceeding 99%, and a reputation score of 97/100. "We felt very good given these rates and scores,” said Chawla. Delighted by these results, Netflix was able to shut down its in-house email solution and migrate 100% of its email sending activities to Amazon SES.

An additional benefit of Amazon SES is its ability to seamlessly integrate with other AWS services. "We are able to get feedback through Amazon SNS about deliveries, bounces and complaints. We integrated with the feedback API, took the data, and graphed it using our internal graphing systems, giving us real-time insight into our email delivery," noted Chawla.  

To learn more about Amazon SES, visit our details page: https://aws.amazon.com/ses/.