Recommendations for ESPs
This article is useful for Email Service Providers (ESPs) and their customers.
We recommend reading the general requirements for all senders in section “Bulk Email Rules”.
Technical recommendations 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 bulk email, 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 bulk email (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 bulk email from several domains (including using the header).
The list of recommendations given above will be added to. It currently includes the most critical recommendations which, if not followed, may impact bulk 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.
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