CSA Certification – What is it about?

Numerous certifications exist in a wide range of fields.
All certifications have one thing in common: they confirm compliance with specified standards and requirements with the aim of creating trust.

The CSA was founded in 2004, with one core goal being to establish quality standards on the market and to enhance the quality of email marketing. The CSA forms the neutral interface between email senders and recipients (mailbox providers).

The CSA certification is designed for senders of commercial emails, helping them to build up a good reputation and enabling deliverability advantages for international mailbox providers. The prerequisite is that senders can deliver commercial and automated emails – such as newsletters and transactional emails (invoices, order confirmations, etc.) – whilst complying with high quality standards (=CSA criteria).

CSA criteria – Best practices that meet  market requirements

First of all, it is important to clarify that these standards were not simply concocted by the CSA, but are based on ongoing collaboration with partners and comply with the legal standards for email marketing.

To be more precise, they are

a) the requirements of MBPs and spam filter providers. In other words, those who decide whether emails end up in the inbox or in the spam folder.
b) Legal standards, such as the GDPR, which must be complied with when delivering commercial emails.

All of the above specifications are continuously adapted to the market.

To give you a broad idea of which criteria must be met, here are some examples:

  • Sending of emails only with existing consent
  • Unsubscribe option in every email
  • Legal notice in every email
  • DKIM (DomainKeys Identified Mail) to ensure authenticity
  • SPF (Sender Policy Framework) to protect against falsification of the sender address

The complete CSA regulations are available for everyone to view and are linked here (CSA Criteria, CSA Conditions of Participation, CSA Rules of Procedure)

Insights into performance and follow-up measures are essential for reputation

Every company sending emails to its customers wants the emails to reach the recipient. However, as we all know, not all emails – by a long shot – end up in the inbox. Mailbox providers must protect their users from unsolicited emails. The decision as to whether an email reaches the inbox or ends up in the spam folder depends on a great many factors. But fundamentally, this is all about trust and reputation, which is critical to performance. CSA certification helps to build these factors.

How it works in detail:

The IP addresses of certified CSA senders are listed on the CSA Certified IP List, which mailbox providers can access and which they then recognize as trusted senders. Unfortunately, it is a myth that being on the IP List goes far enough to guarantee problem-free deliverability.

This trust bonus can help the sender achieve better deliverability. However, senders should not just sit back and hope that this will deliver all of their emails. The sender’s job is to work with the data they receive from the CSA. The CSA data comes from a variety of sources and can help senders identify vulnerabilities to protect and continually improve their reputation.

The following data is currently provided to CSA senders:

Spam Complaint Rate
The spam complaint rate indicates the percentage of spam complaints in relation to the total number of emails delivered. This feedback provides senders with information about how many people flagged an email as spam.
The spam rate should be monitored continuously and should always be below 0.3%. This feedback allows the sender to react early and avoid loss of reputation.

A spamtrap is an email address that is not used by an actual person. Its purpose is to find email senders who send unsolicited emails. Spamtraps are typically used to improve spam filters by identifying and blocking IP addresses that send email to a spamtrap.” (from “Help, I’ve Hit a Spamtrap!“) Using this daily information about spam traps that have been hit, senders can quickly work on root causes before IP addresses are blocked.

DKIM Errors
DomainKeys Identified Mail (DKIM) is an email authentication method designed to detect falsified sender addresses in emails. If there are errors in DKIM, it can have a serious impact on deliverability. CSA senders receive feedback from mailbox providers on missing and invalid DKIM signatures and can prevent undetected errors from jeopardizing email deliverability.

Individual user complaints
The eco Complaints Office, which handles complaints management for the CSA, provides information concerning individual user complaints about unsolicited emails, so that CSA senders have an additional source to identify unqualified data.


How does a CSA certification function?

Senders must comply with high quality standards (CSA criteria) for CSA certification. The assessment process then checks whether the CSA criteria have been fulfilled. The process includes a legal assessment, a technical assessment, and a reputation assessment. The business model and motivation for certification are also evaluated. The CSA Certification Committee, which consists of various representatives from the market, decides whether certification can be granted.



Reputation is a critical factor when it comes to email deliverability. If senders adhere to best practice quality standards and monitor performance continuously and meticulously, they can develop a strong reputation and maintain it in the long term. The CSA provides certified mailers with the data required to do this. But for successful email marketing, it’s the sender’s job to work with the data, to identify weaknesses, and to rectify these.

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