[LinuxBender]

will not be categorized as spam if I email the conventional gmail

There will be many recommendations here about affordable and reliable email providers. I can name a couple if you really want. As for not being categorized as spam, all bets are off. Based on a myriad of posts here over the past year about gmail it seems their spam filters/detection have been a moving target and highly unpredictable.

As for recommendations, I set up Fastmail and several custom domains for family members to create aliases email canaries and they have been happy with it and not been flagged as spam when emailing gmail thus far, but that could change. I also use it for specific use cases. They have good documentation and support. They integrate well with Thunderbird which also makes it easy to each non technical people how to encrypt their emails in my opinion, though others here have had bad experiences with this.

My own personal theory of which I have absolutely nothing to back this up with other than a gut feeling is that Google likely realized the benefits of gathering data from their free email service is not worth the cost and are likely instead focusing on b2b commercial products like corporate email, google docs, etc... Breaking the spam filtering could be a passive-aggressive way to get people to move off the product without having to outright cancel it and deal with the blow-back. But I could be wrong.

[massaman_yams]

Delivering to gmail is unpredictable when you try to send from IP space with unmanaged or poorly-managed IP range reputation, like most low-cost VPSes or residential ISP IP space.

Incidentally, I'm pretty confident the same filtering engine runs both gmail and google workspaces spam filters. Perhaps with some minor differences.

If you're paying for an email service from a respected provider like Fastmail, they almost always have professionals managing IP range reputation, so gmail delivery ends up being significantly more predictable. Make sure you set up DKIM/SPF if you're sending from your own domain.

The reasons Gmail's filters tend to generate complaints that surface on HN is:

  1) IP range reputation can frequently be a stronger spam signal than individual IP reputation  
  2) Most people aren't aware how much of an impact IP range reputation can have on delivery  
  3) There's no way to publicly check IP range reputation with gmail

Some commenters here also significantly underestimate the challenges and complexity of running spam filters at scale.

Disclaimer: I don't work for google or fastmail.

[mikece]

I recommend Fastmail as well.