Last updated: May 28 2018

Area: Episerver Campaign Applies to versions: Not applicable


Are you investing a lot of time and creativity in the design of your mailings – only to find that their deliverability rates leave a lot to be desired? Or maybe you either cannot or do not want to outsource your mailing lists to an external system? Then we are sure that our SMTP API is the dispatch solution you have been looking for. Conversion is extremely resource friendly, because you can continue using your own software for design, distribution and recipient data management. You profit from our high-performance dispatch infrastructure as well as the reputation among internet service providers Episerver enjoys both in Germany and around the world.

Regardless of whether it is transactional emails from your online shop, marketing emails from your content management system or specially designed campaigns for special occasions – dispatch via our SMTP API means your emails are certain to reach recipients. You will not need to hire a deliverability expert or set up an elaborate server structure to obtain significantly higher delivery rates. All you need to do is take advantage of our years of know-how, technical capabilities and deliverability management skills.

Here is how you will benefit:

  • Above-average email delivery rates and reputation
  • Seamless integration into existing system architecture
  • Mailing development and recipient management using your current system
  • Deliverability monitoring by our deliverability experts
  • Quicker and more reliable distribution, even for large recipient lists

Technical implementation

A client for use by Episerver Campaign is required for the installation of SMTP API. If you are not already an Episerver customer, our support team can install a client for you. To activate the interface, we will need to have the IP addresses you use for sending out emails. You will need to register the email server as SMTP server, together with authentication, in your distribution system. Our support team will provide you with this information. In addition, we also require a sending domain that corresponds to the host name of the sender address. If, for example, you send out your mailings from the address "newsletter@news.example.com", then you will need to enter the sending domain "news.example.com". This domain will be delegated to Episerver.

Standard distribution

The requirements described in the previous paragraph are sufficient for standard distributions. Distribution is handled internally via a mailing ID. Billing for emails sent occurs monthly and is based on this mailing ID.

Distribution through sub-clients

If you are an agency tasked with sending out mailings for a number of different clients and therefore need to bill each separately, it is possible to address different mailings through a single ID that is integrated into the email header. Our support team will provide you with the code and relevant ID. Simply integrate this code into the email header of the mailings you wish to send out.

Response management

By carrying out distribution through SMTP API you will also be able to take advantage of our response management. This ensures that blocked email addresses and those email addresses that have exceeded a set limit of hard or soft bounces will no longer receive mailings. This helps contribute to our reputation by maintaining exceptionally high delivery rates for mailings sent through Episerver. To use bounce management, installation of the SMTP API requires an email address where we can forward all returned emails. This forwarding address is obligatory and may not be part of the sending domain.

Why is an email not being delivered?

An email sent via SMTP API may be undeliverable for a number of reasons:

  1. Delivery may fail if the server charged with delivery does not recognize the email address (hard bounce) or the mailbox is temporarily unavailable (soft bounce).
  2. Delivery may fail if the mail server at Episerver is unable to verify the email header or associate it with a mailing.
  3. An email will not be sent if the recipient's email address is on a blacklist or if it exceeded the bounce limit.

What we need from you to install the SMTP API

In order for our support team to be able to install the SMTP API, you need to provide us with the following information. Fill out the PDF form you get from the customer support to set up your client and email it to customer support.

  • Requested name of your client (or the name of your current Episerver Campaign client)
  • IP address(es), to be used to access the SMTP interface
  • Sending domain
  • Email address for bounce management – the host name of this address may not be the same as the sending domain name.

What you receive from us to install the SMTP API

Once your client and SMTP API has been set up and configured, our support team will provide you with the following information:

  • Name of the SMTP server
  • SMTP authentication
  • An email header code for distribution via several mailings

What you need to do in your system

Configure your dispatch system using the data you received from our support team. Once this is completed, you can then begin sending out mailings via the SMTP API:

  1. Delegate the sending domain to Episerver. Instructions can be found here.
  2. Add the name of the SMTP server smtpapi.campaign.episerver.net, the SMTP authentication and the Port 25 to your dispatch software. To ensure that the authentication data is transmitted encrypted, TLS encryption must be enabled. The certificate Thawte SSL CA of the certification authority Thawte must be known as a trusted certificate in your dispatch software.
  3. If you are sending via several mailings, include the email header code in the header of the mailings.

Technical specifications for emails sent through the SMTP API

When submitting an email for dispatch to Episerver Campaign, the following rules must be observed. Otherwise, the dispatch will be aborted:

  • The size of each email must not exceed 300 KB.
  • A message ID header must be set and must have the pattern <32hhr34-42hkjh42@example.com>.
  • The email must contain exactly one "to" header with a valid email address.
  • The email must contain exactly one "from" header with a valid email address. The domain of this address must be identical with the sending domain configured in your client.
  • No cc or bcc header must be set.
  • The subject must not be empty.
  • A maximum of one "reply-to" header must be set.
  • If you use an email header code (X-bm-mailing) from Episerver to address a specific mailing, this code must be valid.
  • Envelope "sender" and "from" header must be identical. The domain of the sending address must be identical with the sending domain configured in your client.
  • The organizational part of the Return-Path header (envelope-from) must match the organizational part of the From header.

    Example domain in Return-Path header: Steps 1 to 4 as described here.

    Example domain in From header: Step 5 as described here.

  • No return-path must be set.

Do you have feedback on this documentation? Send an email to documentation@episerver.com. For development-related questions and discussions, refer to our Forums on https://world.episerver.com/forum/