Mailbox Taxi vs CodeTwo — desktop IMAP vs cloud M365 tool

CodeTwo and Mailbox Taxi solve overlapping problems with very different shapes. CodeTwo is a mature Polish vendor known for its tenant-to-tenant tooling, with both cloud and on-prem options and strong Microsoft 365 coverage. Mailbox Taxi is a desktop-first IMAP tool aimed at engineers who want every byte of mail to travel directly between source and destination, on hardware they control. If your migration is M365 to M365 with calendars and contacts, you will lean one way. If it is messy multi-provider IMAP work, you will lean the other.

TL;DR — when to pick which#

Side-by-side comparison#

Where Mailbox Taxi wins#

There are four practical places where Mailbox Taxi has the upper hand. None of them are slogans — each one matters during specific kinds of migration work.

Data-residency confidence#

Because Mailbox Taxi runs on your machine, the message bodies and attachments never sit in a third-party cloud. For projects with a data-protection officer who needs to write a one-pager describing where the data is during the migration, "it goes directly from one IMAP server to the other over a connection on our engineer's laptop" is much easier to defend than "it lives temporarily in our vendor's Azure tenant."

IMAP breadth#

CodeTwo treats IMAP as a secondary source. Mailbox Taxi treats it as a first-class one, with per-provider profiles for the common server quirks: Gmail label conversion, Outlook special folder handling, Yahoo's connection limits, Zoho's two-factor flow, and so on. If your scope is "consolidate four small companies on four different IMAP hosts into one M365 tenant," Mailbox Taxi will be less work per provider.

One-time price for high-volume engineers#

Per-mailbox pricing is fine when you have one migration this year. If you are an MSP running migrations every month, a desktop license that doesn't meter mailboxes is structurally cheaper. Our list of MSP-friendly migration tools digs into the math.

Pause, inspect, resume locally#

Mailbox Taxi keeps job state on disk. You can stop a 200,000-message sync, close the laptop, change a throttle setting, and resume on Monday without losing duplicate-detection state. CodeTwo can pause too, but the inspection loop on a local tool is faster simply because the logs are right there in your file system.

Where CodeTwo wins#

CodeTwo is not the underdog here — it has a long track record and serious engineering behind it. There are several places it cleanly beats Mailbox Taxi today.

Tenant-to-tenant Microsoft 365#

For a full M365 tenant move with mail, calendar, contacts, OneDrive and Teams chats, CodeTwo's coverage is broader. Mailbox Taxi handles the mail portion only. If your project plan includes "and also migrate the OneDrive content," CodeTwo finishes the job in one tool. See our tenant-to-tenant migration guide for a sense of how much scope creeps in around mail.

Calendar and contacts#

A real one. Mailbox Taxi is an IMAP mail tool and does not currently move calendar items or contact lists. CodeTwo handles both inside the same project, which matters for any migration where end users expect their meeting history to come with them.

Documentation and predictable support#

CodeTwo's documentation library is one of the better ones in the migration space, with knowledge-base articles that go deep on common errors. Mailbox Taxi is newer and the docs are still growing. If you value "I can probably find a step-by-step for my specific edge case," CodeTwo has the advantage today.

On-prem option for highly regulated estates#

CodeTwo offers a server-installed variant for organisations that cannot use cloud at all. Mailbox Taxi covers the same ground in a different shape (local desktop) but if your environment specifically requires "installed on our domain-joined server, run by our admin," CodeTwo's on-prem product has the form factor.

Pricing comparison#

CodeTwo

• Office 365 Migration: roughly $10–$15 per mailbox depending on bundle.
• Volume discounts kick in at 50+ mailboxes.
• Backup and signatures sold as separate products; do not assume one license covers everything.
• Annual subscription model for the cloud variant; perpetual license available for some on-prem products.

Mailbox Taxi

• One-time desktop license, pricing not yet announced.
• Per-engineer or per-machine license (not per-mailbox).
• No subscription required to keep using a migrated mailbox.
• Join the waitlist to be notified when pricing goes live.

For an MSP running roughly 200 mailboxes a year, the per-mailbox math on CodeTwo would land around $2,000–$3,000 in license fees. A flat desktop license on the Mailbox Taxi side is likely to be materially less, but the trade-off is that you do not get CodeTwo's calendar and OneDrive coverage. Spend in the right places.

Decision framework — which fits which reader#

The Microsoft 365 admin doing a tenant merger#

Two companies merging. Both on M365. You need mail, calendar, contacts and OneDrive moved on the same weekend. CodeTwo is the closer fit because it covers all four in one project. Mailbox Taxi would force you to use a second tool for calendar and OneDrive.

The MSP with a rolling book of small migrations#

You move 10–30 mailboxes a month across half a dozen providers. Per-mailbox licenses come straight out of your margin. Mailbox Taxi wins because the desktop license costs the same whether you do 10 mailboxes or 300. The only caveat is calendar/contacts — if a particular client needs those, you slot in CodeTwo for that one project.

The compliance-bound migration#

Healthcare or legal estate. Your DPO has explicitly said mail content cannot pass through any third-party cloud during the move. Mailbox Taxi is the easier sell because the architecture is "it never leaves your machine." CodeTwo's on-prem variant is also defensible but adds server provisioning work.

The mixed-provider consolidation#

Four acquired businesses, four mail providers, one target tenant. Mailbox Taxi because per-provider IMAP profiles are the thing it does well. CodeTwo can do parts of this but is not its sweet spot.

How each tool handles the gnarly bits#

OAuth and modern auth#

Both tools do OAuth 2.0 for Gmail and Microsoft endpoints. CodeTwo runs its OAuth consent through its own app — you grant their app permission on the source tenant. Mailbox Taxi runs the OAuth flow locally, so the token lives on your machine. Neither is "more secure" in a technical sense; they encode different trust assumptions. If your risk register has an entry for "third-party app permissions on production tenants," that one entry decides the call.

Throttling#

The hardest moment of a real migration is the throttle ceiling on the destination. Microsoft 365 throttles aggressively per-connection and per-IP. CodeTwo's cloud will hit those endpoints from CodeTwo IP ranges, which means you share a throttle budget with their other customers in your region. Mailbox Taxi runs from your IP, so the throttle budget is yours. On a Friday-night migration with no other tenants competing, the local tool tends to push faster.

Error inspection#

Both tools surface the messy 5%: Folder UTF-7 conversion error, Message too large for destination, OAuth2 token expired, Too many simultaneous connections. The difference is the loop time. Mailbox Taxi puts the logs on your file system, so a grep is faster than a portal click-through. CodeTwo's documentation is genuinely good at explaining what each error means; Mailbox Taxi is younger and the troubleshooting library is still being built up. See our complete email migration guide for the patterns that show up regardless of tool.

When to use both#

Hybrid is common. CodeTwo handles the main M365 tenant cutover with calendar and OneDrive. Mailbox Taxi handles the long-tail of IMAP mailboxes from acquired businesses or contractors that the per-seat license cannot economically cover. Treat them as complementary, not competitive, when the migration scope is wider than mail alone. The Office 365 migration guide shows where this split tends to happen on real projects.

FAQ#