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I’m Simone Silvestroni 👋

I design and code accessible websites since 1998, now using Jekyll and WordPress.

Email migration from Proton to Mailbox

The main reason for embarking on such a task has a very short answer: I can’t support the fact of being trapped in a walled garden. When I chose Proton years ago I wasn’t bothered by the concept.

It also costs more than, the competitor that mostly appealed to me, while offering less features. I’m going to save around €20 per year: money that can be redirected to other digital venues.

With Proton I’m not allowed to use any system app such as Calendar and Contacts, which makes a proper sync quite cumbersome. External email clients are barely supported — on desktop only — and require a special application called Bridge running in the background at all times. It supports a very limited number of mail applications, such as Apple Mail, Thunderbird and Outlook. is hosted in the EU (Germany) on green servers.

The process

The following has been done on macOS (Catalina).

After getting the gist of how the various services and settings work in my new Mailbox account, I’ve added €3 to become a paying customer. I like this formula, as it leaves me free to fully experiment for a while without committing to an annual payment yet.

I got 50 aliases, including for my custom domains. Setting them up was as easy as adding a bunch of DNS values (TXT and MX) after authenticating the domains with Mailbox. I also improved the spam reputation by setting up SPF, DKIM and DMARC.

Mailbox gave me automatic configuration profiles for email, calendar and contacts. While preferring a manual setup for IMAP and SMTP on, I’ve chosen the easy and fast procedure for calDAV and cardDAV.

Next, I’ve exported a full backup of contacts and calendars from Proton. Importing them back on Mailbox was straightforward: all I’ve used was the import functionality from the default integrated Apple applications. To move the entirety of my 25-thousand emails I relied on a manual migration: selecting large chunks of messages at a time (around 1k), using no issue whatsoever.

All in all, despite dreading the idea of wasting time and energy, it was a surprisingly quick job. From start (zero experience with to finish it took no more than a couple hours.

Side effects

Migrating a whole email system isn’t limited to the above. There’s also the most frustrating consequence of a bad choice: having a gigantic number of accounts registered with an email address tied to Proton. Could be Gmail or a free Outlook or iCloud or whatever: anything that ties me to a system that’s closed in itself and completely outside my control is awfully shortsighted.

I had to alter all my accounts, swapping an address that I’m going to lose soon with one from a personal domain. My domain is under my full control: I can move it from hosting to hosting, change DNS, nameservers, whatever — it stays with me, while everything else can disappear. Google, Microsoft, Apple could close my account on a whim, good luck trying to get them back.

In the end, changing email address for a multitude of online accounts took longer than the entire migration. Especially government services.


This was the surprise I enjoyed the most. Being on Android, I feared the idea of having to look for good apps that can support cardDAV and calDAV natively. While reading Mailbox FAQs, I stumbled on an article where they suggested a FOSS app available on F-Droid called DAVx5.

It was just a matter of adding the single Mailbox account in the app and activate calDAV and cardDAV. Afterwards, the integrated Contacts and Calendar apps by Google would simply sync to it. I feel obliged to repeat that I don’t have a Google account set up with my Android phone, and yet they work seamlessly with Mailbox through DAVx5 sync.

Email on Android was as easy as setting up a single account on K-9 and adding all the identities connected to my domains.


Only time will tell, but I’m very impressed by Mailbox so far. Can’t wait for the first month to end so that I can commit for a full year.