The three simple rules you should follow to make sure your newsletter won’t be considered as spam.

Published by Noé Soriano on July 9, 2019

Before getting into the main topic of this article, I would like to clarify that if you follow these recommendations, you will have much more chances of sending your newsletter to the inbox of your subscribers. However, both B2B filters such as Spam Assassin and B2C ISP filters as Smartscreen have their own rules, which can be changed at any time.

If after following these recommendations you still have problems, you will need to investigate your particular case, as many other factors may affect the delivery rate of your emails.

After explaining that, we can begin. In this post, we will analyze these three points that we will have to understand to deliver our newsletters to the inbox of our subscribers.

Let’s see

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1. Respect local and ISP regulations

We can define this first point as: You should always obey regulations such as the European GDPR or the American CAN-SPAM and the internal rules imposed by the leading ISPs, such as Gmail, Hotmail, etc. This explanation could seem complex,  but we can summarize everything in these brief basic guidelines:

1.1 Send your email marketing campaigns only to subscribers who wish to receive them. When someone wants to receive your emails, this person should register voluntarily through a web form (double opt-in). You should also clearly explain what will happen after the subscription, what you will send to your new subscribers and how he/she may request removal from your email list.

1.2 Always add an easy-to-use unsubscribe link to remove automatically all subscribers who no longer want to receive your messages. You should include a legal notice in the footer of your emails, with information about your campaigns and contact information.

1.3 Don’t send messages to bounced emails or inactive subscribers. You should also not work with a mailing list created by third parties neither sell or loan your list, even if you have warned that their data could be shared with other companies in the future.

Keeping your mailing list clean will be key to improving your delivery rates.

Configurar correctamente a nivel técnico el remitente que utilizaremos

2. Set up correctly the sender email address you will use

We recommend that you contact your webmaster or your hosting service to ask them to help you add these settings. This can sound annoying because it is very technical, but the process is not that difficult, and you only have to do it once.

Point 2.1 on SPF is really essential, and the other aspects are strongly recommended, but if your campaigns are not being delivered, you will have to add all of them at once. Let’s review all of them:

2.1. SPF record: This is a TXT record that you should add to the DNS of the sender domain. This protocol will tell all the servers that receive your emails that the sending IPs can send messages on behalf of this domain and what the server should do with unauthorized IPs. (you can find more information here)

2.2. DKIM key: This is a system that will add a signature to the emails sent by the domain and authenticate the content and domain that sent the newsletter. When filters receive an email with this key, they will check it to see if it is correct or if the message was sent by a server that wasn’t authorized. (you can find more information here)

2.3. Domain checks on postmaster systems: These TXT records are requested by the postmaster and FBL systems of Gmail, Office 365, etc. To verify ownership of the sender’s domain.

2.4. Email addresses requested by ISPs and Yahoo FBL: Besides the sender email, you should create the emails [email protected] and [email protected] (you should change “” for your real domain)

2.5. Website 100% published. This point is critical: You should never work with a domain purchased just for sending emails, you should send your newsletters with your official corporate domain, if possible with SSL. You should also include a link where your visitors can find your privacy policy and actual contact and product information or services that you are offering.

2.6. DMARC: The sending domain should have the DMARC system configured to prevent identity theft. (You should contact your hosting service for more information about adding it to your domain.)

Procurar que el diseño del boletín no suba el spamscore

3. Make sure the newsletter design is not affecting the spam score.

The spam score is a metric system that will determine parameters to define whether a message could be considered as spam or the filter can delivery it to the inbox.

It is used by all antispam systems, and it will add or subtract points by different rules and calculate whether the sum will exceed the value set by the system to determine if the message is secure or not.

In other words, this system will check the subject line, the HTML, links, and the text of your email. To avoid these problems, you should pay special attention to these aspects:

  1. Don’t write the whole subject line in capital letters
  2. You should always send a newsletter with clean HTML, with images and texts
  3. Don’t add large fonts or bright colors
  4. Don’t add texts to images or words usually used by spammers

In fact, adjusting our newsletters to these standards is very easy, but if you need more information, please contact our support team.

· Conclusion

I wanted to write this article as a glossary and not as a compendium of documentation, and that is why I included links to articles for the points that I considered more relevant. The idea was to publish a guide to help you understand aspects you will have to check when you have problems related to spam.

Before we finish, I would like to give you a list of aspects that you should check before you send a newsletter.

►  Respect local laws and create a double opt-in mailing list:

  1. Explain clearly what you will send in your emails.
  2. Ask them to confirm that they really want to receive your newsletters.
  3. Make sure you are only sending emails to double opt-in subscribers.
  4. Add an unsubscribe link and legal notice.
  5. Make sure you are working with a clean database.
  6. Never work with a purchased mailing list or share your data with anyone.
  7. Understand local regulations and general ISP rules

► Technical Settings:

You should add and check these settings for all domains that you will use:

  1. SPF record.
  2. DKIM key.
  3. Postmasters systems.
  4. Email addresses abuse and postmasters active and regularly monitored.
  5. 100% published a website with SSL and a link to the privacy policy.
  6. DMARC System.

► Review the layout and content of your emails

You should also review the content and design of your newsletters:

  1. The subject line should be clear, concise, and should not be written with all words in capital letters.
  2. Your design should include an HTML table, text and images, unsubscribe link, and legal notice.
  3. Don’t use large fonts, bright colors, and code that could be incompatible with email marketing.
  4. Don’t send emails with words or phrases commonly used by spammers.

Noé Soriano

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  1. Eva

    Un contenido muy interesante. Tras leerlo me surgen 2 dudas sobre la parte técnica:

    1. [email protected] y [email protected] ¿tienen que existir realmente o simplemente no rebotar? Quiero decir, si tengo configurado mi servidor para que todo correo que llegue a una cuenta inexistente se redirija a otra concreta ¿sería suficiente? ¿y estos correos sólo tienen que existir o también hay que incluirlos en alguna parte del mensaje (firma)?

    2. ¿Y cómo se configura el DMARC en MailRelay?
    Un saludo y gracias por los contenidos del blog.

    11/09/2019 - 06:50:49 Publicar una respuesta
    • Noé Soriano

      Hola Eva, gracias por tus comentarios. Te contesto:

      1. Sí, deben existir y ser revisadas de vez en cuando ya que su objetivo es recoger las quejas de posibles usuarios que reciben spam desde tu dominio y consejos o comunicados de ISP, proveedores de internet, etc. Además la de postmaster es necesaria para configurar el DMARC. Lo que si puedes configurar es un alias/redirección a otra cuenta final si no quieres tenerlas físicamente configuradas en tu panel de control de correo.

      2. El DMARC es un sistema totalmente independiente de Mailrelay, es decir no tienes que añadir nada en concreto nuestro como por ejemplo con el SPF. Para configurarlo debes consultar a tu proveedor de hosting para que te indique como hacerlo ya que puede variar de uno a otro. Aquí tienes un manual general pero debes asegurarte con tu proveedor.

      un saludo

      11/09/2019 - 08:34:44 Publicar una respuesta
      • Eva

        Muchas gracias!!

        11/09/2019 - 12:59:10
  2. Steven Baughman

    Does the European anti-Spamalot refer only to commercial emails? What about political emails? Or religious emails?

    10/09/2019 - 11:23:05 Publicar una respuesta
    • Noé Soriano

      Tampoco se puede enviar sin permiso este tipo de correos. Es cierto que algunas normativas como la LSSI solo hacer referencia a envíos comerciales pero en estos dos casos en concreto entraría en juego el RGPD que si protege a los usuarios contra este tipo de envíos de hecho de forma mucho más estricta ya que serían datos privados de afiliación política y religiosa que se considerarían de especial protección y no de nivel básico.

      Como norma general sencilla y aplicable a todos los casos y temáticas, solo podemos mandar a suscriptores mayores de edad, que deseen recibir nuestros comunicados, se haya suscrito y confirmado de forma totalmente consciente e informada, activa y fehaciente con un sistema doble optin y cumpliendo las normativas de protección de datos.

      11/09/2019 - 08:46:32 Publicar una respuesta
  3. Yomismo

    “y las buenas prácticas de envío que exigen los ISP como gmail, hotmail, etc.”
    Estos no son ISP, los ISP son Movistar, Vodafone, etc…

    10/07/2019 - 12:38:44 Publicar una respuesta
  4. Cecilia

    Muchas gracias, nosotras tenemos unos cuantos rebotados desde hace tiempo a los que les poníamos el mail a mano desde outlook. Ya no lo haremos 😉

    09/07/2019 - 11:00:34 Publicar una respuesta

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