Fastmail vs. ProtonMail: A Comparison (opens in new tab)

> Fastmail’s email search features also allows you to search for emails based on their content or attachments; ProtonMail’s search function doesn’t let you search through email contents unless you ask it to download all your email to your browser’s cache.

That's inconvenient, but entirely the evidence that they're storing your data correctly. If they could build indexes of your email contents, that would defeat the purpose of private email.

At the end of the day, if Fastmail gets breached they take everything. If Protonmail gets breached they take email datetimes and subject lines.

Doesn't this imply that Fastmail has access to the decrypted contents of messages?

They could have just come to the conclusion that if you want ultimate "privacy" and be sure that no one can read your emails "at rest" take Protonmail if you want features take fastmail. That would have been a fair assessment, the way it's written now just makes it come across as a advertisement piece. Maybe they feel customer's moving to Protonmail.

P. S.: I say this as a happy fastmail customer

ProtonMail and Fastmail serve very different threat models, and glossing over the differences between end-to-end encryption and not is disappointing. I choose Fastmail because my threat model isn't particularly concerned about the company's servers or government intrusion, but for the folks who do need to worry about that, Fastmail isn't a good option, and even a Fastmail blog should be willing to plainly and openly admit that.

If anything, Fastmail should even encourage people living under oppressive regimes or involved in sensitive whistleblowing activities to consider ProtonMail... even if they then use Fastmail for everything else.

might be, but I'd prefer to hear it from someone else.

Not necessarily a bad thing. I genuinely don't know which is better. But under each heading there are three paragraphs talking about Fastmail and one for ProtonMail, so I wouldn't exactly call it balanced.