Rules for ESP
This article is useful for Email Service Providers (ESPs) and their customers.
We recommend reading the general requirements for all senders in section "Mailing rules”.
Technical requirements for ESPs
- For each customer, use its domain in the “From” field.
- Do not use free-mail addresses for email distributions.
- Do not send a customer’s email distribution from the ESP’s domain
- Keep in mind that an existing customer may also enable/turn on a DMARC policy (including p=reject).
- Precedence: bulk
- List-Unsubscribe: <valid link to unsubscribe>.
Support for mailings, including from individual clients
- Use statistics on Postmaster:
- Regarding your own DKIM (track your reputation).
- Regarding the client DKIM, if possible (track your client’s reputation).
- Regarding the types of client mailing (track the reputation of specific types of email using X-Mailru-Msgtype.
- Statistics on Postmaster.
- SMTP replies with 4xx codes
- SMTP replies with 5xx codes
- Delivery to Spam folder
Preventative measures to reduce the number of complaints and spam
- Verify ownership of the domain.
- Deny or moderate bulk emails distributed from trial accounts to real databases via the service. Messages from trial accounts must also have headers with an appropriate X-Mailru-Msgtype: trial-<> mask.
- For new clients:
- Be sure that subscription’s DOI mechanism works
- Evaluate the database’s quality using third-party and/or in-house services.
- Perform A/B testing on small segments of the database and determine the ComplaintRatio and SpamRatio.
- Identify clients sending mailings from several domains (including using the header).
The list of rules includes the most critical requirements which, if not followed, may impact email deliverability for individual clients, as well as email deliverability for the entire ESP.
If you are an ESP’s customer, find out whether your ESP follows these recommendations. The answer could determine whether your messages are delivered or not.
Обновлено 4 ноября 2021 г.