Are you having difficulties getting mail delivered to German mailbox providers such as,, and  If so, you are not the only one.  After pouring through postmaster pages and having many email conversations with support teams, here is what I have found to be the key items that you should pay attention to when sending to German providers.  

Standard Best Practices

As with all providers, German providers expect the sender to follow email best practices; provide an opt-out method, conform to RFC standards, authenticate with SPF and DKIM, and send relevant email to engaged recipients.  

Postmaster Pages

When in doubt, read the postmaster page.  You can find the postmaster page by adding the word, ‘postmaster’, in front of the domain (Ex:  This page will define the provider’s Acceptable Use Policy (AUP) – rules that a sender must follow in order for the mail to be accepted.  In addition, this page may also provide important information such as explanations of error messages and troubleshooting tips.  

Complaints and Spam Traps

German providers take privacy very seriously.  What a reader does with their mail (open, read, or delete) does not have a large impact on where your email lands (inbox, spam folder, or not accepted).  Some of the key factors are the volume of complaints being generated for an email campaign and the number of spam trap hits the provider is seeing.  Of course, all email providers use filters as well which help them to identify spam, and additional information is received from external sources such as the Certified Senders Alliance organization. 

DOI Consent

German providers are more strict than other providers when it comes to recipient consent. The reason is that in addition to GDPR, German providers must abide by German-specific laws like the Federal Data Protection Act (BDSG) and the German Act Against Unfair Competition.

These laws make it clear that when sending marketing email, senders must have proof that consent was obtained from the recipient.  And, although these German laws do not specifically state that double opt-in is required, it is the most reliable method of proof to show that a recipient has consented.  This is why German mailbox providers enforce the double opt-in method of consent.  In fact, T-Online explicitly states that they expect all marketing mail to be confirmed by double opt-in as stated on their postmaster page:  

“To deliver mass commercial e-mails, in particular, you require the explicit and personal(!) agreement of the recipient. For practical reasons, this agreement to receive a particular e-mail is obtained almost exclusively by means of double opt-in procedures.”

PTR Records

The PTR record is the opposite of an A record.  It associates the host name with the IP address.  PTR records are oftentimes used in reverse DNS lookups as another way to verify that the email is being sent from a legitimate server.  Most, if not all German providers require PTR records.  The PTR record typically contains the sending ESP’s host name.  For example, SparkPost hostnames have the format,, which is broken down by the following:

mta – indicates the host is a mail server

2-3-4 – is a portion of the IP address – ESP name

T-Online, however, would prefer that the PTR record also include the company name in addition to the ESP name.  For example, for the company Acme, the PTR hostname would look like this,, which is broken down by the following:

mta – indicates the host is a mail server

2-3-4 – is a portion of the IP address – sending domain for Acme – ESP name

This does not mean that email in the first format won’t be delivered, it is just a preference.  


As mentioned above, German providers expect the sender to conform to RFC standards.  More importantly, T-Online has recently (informally) announced that they soon will be expecting DKIM messages to conform with DMARC, meaning the Header or Envelope From (RFC 5321.MailFrom) and Mail From (RFC 5322.From) must be in relaxed alignment (one can be a subdomain of another).  This almost certainly will affect shared pools where the Envelope From is typically not in alignment with the Mail From although, I have not yet seen messages denied for this reason.


T-Online seems to be much more strict than the other German providers.  They enforce DOI, strongly encourage that the PTR record include the company name, and now are hinting at DKIM conformation with DMARC.  If you want your email to be delivered to T-Online, it is important that you follow the sending guidelines on their postmaster page.  One thing to note is, those customers who attract negative attention from T-Online by sending to spam traps or having high complaint rates are more susceptible to the PTR hostname and DKIM alignment rules.

Thank you,

Tracey Crawford

Director of Compliance and Deliverability, SparkPost