I've created an automated script that generates a custom HTML email using PHPMailer within PHP and sends it, from my custom domain email account, to whatever recipient.
The emails are all litmus tested and render perfectly in all clients, hold no comments whatsoever, no strings that seem to be spammy, all good. My domain is also not on any blacklist, etc.
The e-mails first pretty much dropped into the spam for every recipient.
I went back to my hosting service then, and they recommended me to create an SPF - record in the DNS zone of the domain of my e-mail.
This drastically improved the non-spam delivery rate of my emails.
Still, some clients still receive the emails of our company in their junk folder. I ran a spam-test using email on ACID, and all tests were passed, including SPF - record verifications, etc. The only warnings that showed up were, guess what, that for outlook.com and gmail.com, the emails eventually drop into the spam folder (without telling why) which is obviously a big problem.
And indeed, the only clients still complaining about the spam troubles are indeed gmail users, mainly.
I then came across this very interesting post, and learned that google recommends the setup of all, SPF, DKIM and DMARC.
I first of all included the include:_spf.google.com part in my SPF record, but when it comes to DKIM, I'm stuck.
I'm confused if, to have a working DKIM - register within the DNS of your domain, you actually need to have a Google Workspace account? Because apparently you can only create a DKIM Key within that Workspace account, and I'm worried that this will may expire after my 14-trial period of the Workspace account, and rather further damage my email domain reputation instead of actually improving it.
Or am I misunderstanding things, and there's a different solution to setup a DKIM (and then also DMARC) for a given mail client like gmail for a domain? I'm asking because I have no experience whatsoever in setting up DKIM.
In order to set up DKIM from the Admin console you definitely need to have a Google Workspace account. Using a Cloud Identity free subscription would not work as you are not going to have access to services like Gmail.
To simply generate the key from the Admin console you need the right subscription with access to Gmail, which is only available in Google Workspace subscriptions.
It will most likely stop working after your subscription expires since it is linked to the Admin console from the Google Workspace account where it was generated and once the subscription gets suspended everything stops working.