Mailbox.org Alternative: How to Migrate to JustEmails

Mailbox.org is a good provider. The German privacy laws, the PGP integration, the lack of tracking — all good things. But it charges per user, so the bill grows with every mailbox you add, and that adds up fast when you're managing multiple domains, each with a handful of mailboxes. That's usually when people start looking for a Mailbox.org alternative.

Here's the thing: if you're paying per-user for email hosting across multiple domains, you're paying a tax that doesn't scale. JustEmails is $49 a year, flat, for unlimited custom domains and unlimited mailboxes with a unified inbox across all of them — additional team members are $2 per member per month, and storage beyond the included 10 GB is $99 a year per 100 GB. You keep the privacy basics — TLS encryption, full IMAP/SMTP access, proper authentication. You give up server-side PGP, which the PGP section below deals with.

By the end of this guide, you'll have your Mailbox.org mail, folders, and DNS settings migrated to JustEmails. We'll cover the PGP situation (there's a caveat), the actual IMAP sync process, and the DNS cutover. If you're managing email for an agency or multiple projects, our flat-fee pricing breakdown explains why per-user pricing becomes a problem at scale.

What We're Building

A complete migration from Mailbox.org to JustEmails:

• Full email history transferred via IMAP sync
• Folder structure preserved
• DNS records repointed (SPF, DKIM, DMARC, MX)
• New mailboxes created with same addresses
• Existing mail clients reconfigured

What we're not covering: calendar and contacts. IMAP only moves email, and JustEmails doesn't host calendars or contacts. If you're using Mailbox.org's calendar, export it as ICS and import to Google Calendar, Apple Calendar, or wherever. Contacts export as VCF. That's a separate workflow — this guide is email-only.

Prerequisites

• A JustEmails account with your domain already added — the 7-day trial (card required, charged when it ends unless you cancel) covers one domain, two mailboxes and 1 GB of storage, enough to test with one small mailbox before you move everything
• Access to your domain's DNS settings (Cloudflare, Namecheap, GoDaddy, wherever)
• A desktop email client: Thunderbird, Apple Mail, or Outlook — we'll use this as the sync bridge
• Your Mailbox.org IMAP credentials (the email address and password you use to log in)
• 30-60 minutes of hands-on time, plus time for the sync and DNS propagation

One number to plan against before you start: a newly verified domain can send no more than 50 a day in the first week, 200 in the second, and up to 500 from day 15, with mailbox sends and API sends counted against the same daily allowance. That clock runs from domain verification rather than from signup, so the domain you add in Step 1 starts at the bottom of the ramp however old the account is. Copying your archive across doesn't touch any of it; the limit applies to mail you send after cutover.

One more thing. If you're using Mailbox.org's built-in PGP encryption — the feature where incoming mail is encrypted with your public key before storage — read the PGP section below before you start. There are decisions to make.

Step 1: Set Up Your Domain in JustEmails

Log into justemails.app and add your domain. JustEmails generates the DNS records you'll need:

• One MX record pointing to mail1.justemails.app at priority 10
• SPF record authorizing JustEmails to send
• DKIM public key for message signing
• DMARC policy
• MTA-STS records for enforced TLS
• A verification TXT record that proves the domain is yours

Follow the dashboard's verification step, but don't change your MX records yet. The actual MX cutover happens after we've synced all the mail — you don't want to redirect incoming mail until the new mailboxes exist and contain your history.

Create the mailboxes you need. Match the addresses you have on Mailbox.org: if you have alex@yourdomain.com there, create alex@yourdomain.com here. Set passwords. Write them down somewhere secure.

If you get stuck on the domain verification step, our custom domain setup guide walks through it in more detail.

Step 2: Configure Your Mail Client as the Bridge

Here's how IMAP migration works: you connect both accounts to a local email client, let it download everything from the source (Mailbox.org), then drag/copy to the destination (JustEmails). The client does the heavy lifting.

Thunderbird (recommended):

Add your Mailbox.org account:

• IMAP server: imap.mailbox.org
• Port: 993
• SSL/TLS: Yes
• Username: your full email address
• Password: your Mailbox.org password

Let Thunderbird download all folders. This takes a while for large mailboxes. Go make coffee. Check on it in 20 minutes.

Then add your JustEmails account:

• IMAP server: mail.justemails.app
• Port: 993
• SSL/TLS: Yes
• Username: your full email address
• Password: the mailbox password you set in Step 1

Both accounts should now appear in Thunderbird's sidebar.

Apple Mail / Outlook:

Same idea. Add both accounts, use IMAP, same server details. All three work; Thunderbird tends to be the most dependable with large mailboxes.

Step 3: Sync Mailbox.org to Local

Wait for Thunderbird to fully synchronize your Mailbox.org account. Folders populate, message counts climb. A 5 GB mailbox can take a few hours; a 20 GB one can run overnight.

This is the boring part. Go do something else.

How to verify it's done:

Right-click your Mailbox.org account → Subscribe and make sure every folder is ticked. Then compare folder message counts with Mailbox.org webmail — they should match. Also test offline access — disconnect, browse old emails. If they load, sync is complete.

Step 4: Copy Messages to JustEmails

Select a folder in your Mailbox.org account. Select all messages (Ctrl+A or Cmd+A). Right-click → Copy To → your JustEmails account → matching folder.

Start with a small folder — maybe 50 messages. Watch it complete. Check JustEmails webmail to confirm arrival. For large folders, do batches of 500-1000 to spot errors early.

Folder mapping: Inbox → Inbox, Sent → Sent, Drafts → Drafts, Archive → Archive. Custom folders — create matching ones in JustEmails first. IMAP preserves hierarchy, subfolders work fine.

Pro tip: Copy Sent mail. People forget this. Your sent mail is half your history.

Step 5: Handle PGP-Encrypted Messages (If Applicable)

Here's the caveat for privacy purists.

Mailbox.org's encrypted-inbox option encrypts incoming mail with your public key. Those encrypted messages migrate fine — but they arrive still encrypted. JustEmails doesn't do server-side PGP. You'll need a local client with your private key to read them.

Options:

1. Keep using PGP locally. Import your private key into Thunderbird's OpenPGP support. Encrypted messages decrypt when you read them.

2. Decrypt before migrating. Open encrypted messages in Mailbox.org webmail (which decrypts for display), forward plaintext to yourself.

3. Accept the archive. Leave them encrypted. Access with your key when needed.

For most users who enabled PGP "for privacy" but rarely sent encrypted mail, option 1 or 3 works. If end-to-end encryption is critical, consider whether email is the right medium — Signal or Matrix might serve better. (Controversial opinion: email was never designed for secrecy, and bolting on PGP doesn't fix that.)

Step 6: Verify the Migration

Before touching DNS, confirm everything arrived:

1. Log into JustEmails webmail. Browse folders. Spot-check random old emails. Check attachments open.
2. Count messages. Totals should roughly match — drafts and system folders sometimes differ.
3. Check folder structure. Subfolders intact?

Hold off on test sends until after the DNS cutover: until your SPF and DKIM records point at JustEmails, a test message proves little and may land in spam.

If anything's missing, re-sync that folder before proceeding.

Step 7: Cut Over DNS

This is the point of no return. Once you update MX records, new mail goes to JustEmails, not Mailbox.org. Breathe.

Go to your DNS provider. Update these records (exact values come from your JustEmails dashboard):

MX Records: Delete the old Mailbox.org MX records. Add the single JustEmails MX record: mail1.justemails.app at priority 10. Don't add a backup MX.

SPF Record: Keep one SPF record and edit it rather than adding a second — two SPF records make both fail. If yours says include:mailbox.org, replace the whole value with v=spf1 a:mail1.justemails.app ~all. There is no JustEmails include to add.

DKIM Record: Add the DKIM TXT records from your JustEmails dashboard. They're long strings — copy them exactly.

DMARC Record: Keep exactly one record at _dmarc. If you already have one, edit it rather than adding a second — two DMARC records fail the dashboard's check. If yours is at p=none, leave it there for now; we cover moving to p=reject safely in our DMARC enforcement guide. Don't tighten policy during migration.

MTA-STS (optional but recommended): JustEmails provides these records. They enforce TLS for inbound mail from providers that support it.

Save changes. DNS propagation begins. Most resolvers update within 2-4 hours. Full propagation takes up to 48 hours. During this window, some mail goes to Mailbox.org, some to JustEmails. Keep both accounts monitored.

The waiting is the worst part. A Friday-evening cutover means you're not refreshing MXToolbox every ten minutes during work hours.

Step 8: Update Mail Clients and Apps

Once DNS has propagated (test with MXToolbox):

• Desktop clients: change IMAP/SMTP servers to mail.justemails.app — IMAP on port 993 with SSL/TLS, SMTP on port 587 with STARTTLS (not 465)
• Mobile apps: same settings
• Any apps using SMTP for sending — see our SMTP vs API guide

Common Errors and Fixes

"Authentication failed" on IMAP connect

Check you're using the full email address as username, not just the local part. Mailbox.org and JustEmails both expect user@domain.com, not just "user."

Messages appear but are empty / "body not downloaded"

Your client hasn't fully synced. Wait. Or, in Thunderbird, turn on keeping messages on this computer for that account (Account Settings → Synchronization & Storage).

Folder won't copy — "quota exceeded"

JustEmails includes 10 GB of storage, pooled across the whole account (the trial gets 1 GB). If your Mailbox.org mail exceeds that, add storage ($99/year per 100 GB block) or archive old mail locally before migrating.

Sent messages show wrong dates after copy

IMAP preserves message dates. If dates look wrong, your local client might be displaying "received by client" dates instead of original dates. Check message headers — the Date field should be correct.

DNS changes not reflecting

Flush your local DNS cache. On Mac: sudo dscacheutil -flushcache. On Windows: ipconfig /flushdns. Or just wait. Some ISPs are slow.

After Migration Housekeeping

Once stable (give it a week):

• Keep a backup. Hold on to a final local copy of your Mailbox.org mail (Thunderbird already has one from Step 3) before you cancel.
• Cancel Mailbox.org. Don't let it auto-renew. Set a calendar reminder.
• Test deliverability. Send to Gmail, Outlook.com, Yahoo. Run mail-tester.com for a deliverability score.

Frequently Asked Questions

Can I migrate encrypted emails from Mailbox.org to JustEmails?

You can migrate PGP-encrypted email bodies, but they arrive still encrypted. JustEmails doesn't decrypt them server-side — you'll need your private key in a local client like Thunderbird to read them. If your private key lives in your Mailbox.org account rather than on your own machine, export it before you cancel, or decrypt those messages before export.

How long does it take to migrate from Mailbox.org to JustEmails?

The IMAP sync itself depends on mailbox size. A 5 GB mailbox can take a few hours over a decent connection. DNS propagation for the domain switch takes up to 48 hours, though most resolvers update within 2-4 hours. Plan for a weekend migration if you want zero stress.

Will I lose my folder structure migrating from Mailbox.org?

No. IMAP preserves folder hierarchy. When you sync Mailbox.org to a local client and then push to JustEmails, folders come across intact. Labels from Gmail-style providers don't translate perfectly, but Mailbox.org uses standard IMAP folders — those migrate cleanly.

Is JustEmails a good Mailbox.org alternative for privacy?

It covers the basics, but it isn't like for like. JustEmails uses TLS 1.2+ encryption in transit and at rest, with full IMAP/SMTP access. JustEmails doesn't offer built-in PGP key storage like Mailbox.org — if end-to-end encryption matters, use a local PGP client like GPG or your mail app's S/MIME support. For PGP power users, it's a workflow shift.

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