Authentication is the little dark secret ESPs don't talk about to small businesses when selling their email marketing tool. They show you a really cool jazzy email editor, with fun features. They sell a secure, well-organized CRM to save all your subscribers. But they don't explain to you that you need a bit more than a beautiful template and a list of subscribers to get started.
DKIM & SPF have to be implemented before sending any email marketing campaigns from any tool you use. When sending newsletters to your subscriber, their inbox verifies the sender to protect their clients from spoofers and spammers. Think of authentication as a form of formal identification.
!--- As an email specialist (or any other person/spammer who knows what tools to use), I can send newsletters using your company's actual email address. The only difference is that mine can't be and will never be authenticated as I cannot access your DNS panel through your hosting provider (e.g., GoDaddy). Only people with access to their DNS panel and their real email marketing account can send authenticated emails. So if we were to both send emails, yours will end in the inbox... and mine won't because I can't authenticate the sender email.
On the flip side, unauthenticated emails can sometimes end in the inbox. This depends on a million and one variables, just like when underage people try to go into a bar without ID. They can sometimes get away with it, but most of the time, they won't. Ensuring your emails land in the inbox is worth the 5-minute setup, don't you think? ---!
DKIM proves that it is you who is sending the campaign using your company email address.
SPF proves that the system/infrastructure sending the campaign has your permission to send using your company email address, such as Mailchimp or Cakemail.
There are other types of authentication, but let's keep it for another time.
Here is a list of the most common email marketing providers and how to authenticate your domain-based email. Now before anyone panics, I ensure this is a straightforward, easy, o