First, take into account that every recipient server is different and may apply different spam filtering criteria for the messages being received. So you will undoubtedly have some mail filtered at some point when sending email campaigns. This depends on different factors like your domain reputation, the subscriber preferences, among others.
The first filter is usually related to email marketing. by default but you shouldn’t worry about. There are a couple of things you need to consider to make sure you reach the inbox:
Follow Opt-In laws: Email clients (or ISPs) use those guidelines to detect and filter spam, by following those guidelines you are also avoiding to be filtered.
Here are some of the most important laws in the US and Europe: CAN-SPAM act and EU Opt-In Directive.
- Use email authentication: When using an email marketing service, like MoonMail, the platform uses your email address to send campaigns for you, for that, email clients like Google or Yahoo consider the email as not “official”. Add SPF, DKIM and TXT records to verify the sender. MoonMail generates the records for you.
- Remove inactive contacts: If you are sending to many inactive contacts who don't open your emails, ISPs will consider your mail “unwanted” and deliver it to the spam folder.
- Keep your lists cleaned: It's very important to clean your list every now and then to remove inactive subscribers from your list or move them into other lists that get mailed less often. On the other hand, Having a lot of bounces/complaints can give you a bad reputation and eventually lead to a block.
- Don’t send only image emails: Sending an email with just graphic content or the majority of the content are images, it sure will have delivery issues. This is because the ISPs cannot detect the content of the image and if you don’t have text to give context they might think is a threat. Always maintain a good text to image ratio.
- Have the unsubscribe link visible: A spam complaint it’s terrible for your domain reputation and it affects your deliverability. Having unsubscribes is very healthy and it’s WAY better than having complaints. You could add a second unsubscribe link on the top of your email.
- Get off blacklists: If your email is blacklisted, it becomes very difficult to send emails even for the people on your list. Here you can check if your email is on a blacklist server.
It's all about having a healthy and clean subscriber database. Follow these practices to improve your reputation with the IPSs and your emails will hit the inbox.