Esendex constantly look for different ways to optimize and improve the deliverability of your emails. We manage your reputation as a sender and puts authentication tools at your disposal (SPF, DKIM, etc.). We optimize your sending frequencies (throttling) and your HTML code (thanks to the Esendex Email Editor, our online newsletter editor). On top of that, the feedback loops and the statistics allow you to optimize deliverability from one sending to the other.

More than 20% of legitimate emails do not make it to the recipients’ inbox. In order to deliver your emails and reach the intended inbox of your recipients’, a lot of technical constraints must be respected and followed. Esendex all-in-one solution allows you to simplify the complexity of sending your emails successfully.

1. Access to authentication tools: SPF & DKIM

Authentication systems have set of standards for most of the ISPs. These protocols guarantee and protect the identity of the senders as well as fight against phishing. Therefore, it is often necessary to publish these certificates. If this is not done, the ISPs can consider the non-authenticated emails as suspicious and place them in the spam folder.

Esendex implements and optimizes all major email authentication protocols that senders need including DKIM (DomainKey Identified Mail) and SPF (Sender Policy Framework). This can also be personalized for free. If you require assistance in this process, please contact our support team.

2. Optimization of the sending pace (throttling)

ISPs use ‘throttling’ mechanisms to control the volume of data travelling over their networks. Some impose temporary or permanent volume restrictions. The threshold is based on the number of connections between the sending server and the receiving server, the number of messages per connection, and the volume of messages over time. If you attempt to open too many SMTP connections at the same time or send too many email messages within a short time, you are very likely to get errors such as ‘timeout’, ‘server has exceeded the rate limit allowed’, or ‘too many connections from your IP’. If this happen, the reputation of the IP addresses used can have a major effect on these limits. In order to guarantee an optimization of the general reputation, Esendex will slow down and adapt the sending pace when needed. By respecting this imposed variations, the messages are accepted, they do not bounce and get to the inboxes of the intended recipients.

3. Optimization of the HTML structure of the email

Esendex provides an online newsletter tool that gives anyone the ability to get 100% optimized code from the header to the body of the email. All HTML elements abide by the rules and guarantee an improved deliverability. Note that when using this feature, no technical knowledge is required. Always remember that an incorrectly coded email can trigger some anti-spam filters!

4. Statistics, Feedback Loops and the relationship with the ISPs

Esendex strength also resides in the richness of the sending follow-up. Every complaint is traced and taken into account. Thanks to the feedback loops. This is best illustrated when someone clicks on the button “report as spam”. Esendex gets this information and stops sending to this email address. The bounces and unsubscriptions are also automatically managed. This helps in maintaining high quality lists. Anyone who is persistent in sending undesired emails could get blacklisted any moment. Even if the complaints come only from 0.1% of the recipients, this would be enough to get blocked by the major ISPs. In general, Esendex works closely with ISPs and respects all the latest standards and recommendations.