What is actually on offer
The Register's Dan Robinson was invited from the waitlist and describes the service in plain terms. Thundermail is a web-based email service that can also be reached through the Thunderbird desktop app, the Thunderbird Android app, or other compatible email clients. The reporter says the Thunderbird apps stay free. The paid part is the hosted service.
The Register reports this early-access package:
- Up to 15 email addresses and three custom domains
- 30 GB of mail storage
- 60 GB of storage for Thunderbird Send, an end-to-end encrypted file-sharing and large-attachment tool
- A signup price of $6 per month billed annually, which the reporter says is roughly the £55 paid for a year of early access
These are signup and early-access figures. They are not confirmed final pricing. Thunderbird said in June that more pricing tiers will come once Thundermail is out of beta, and the Register also notes that the organisation plans extra features at different price points.
Why the name changed
Thundermail began as part of Thunderbird Pro. Thunderbird said early feedback showed people cared most about Thundermail, and that the "Pro" label confused people about whether Thunderbird itself was becoming paid. Thunderbird Pro is now simply Thundermail, with the scheduling tool Appointment and the file-sharing tool Send included. The desktop and mobile apps remain free and work with any email service.
The original April 2025 announcement set the project's goals. It promised an email service with calendars and contacts, an ad-free offering that doesn't sell or train AI on user data, and open-source software. Those are stated aims. They don't by themselves prove how the service handles security or data in practice.
Webmail is still experimental
The webmail interface is the feature early testers can now see. The Register describes a Gmail-like layout with folders on the left and messages on the right. It also lists drafts, scheduled sending, folders, contacts and multiple identities. The reporter admits limited testing time and says nothing surprising turned up.
Thunderbird's own roadmap is more cautious. It treats webmail as an experimental feature for users willing to try new things early, with an initial scope limited to basic folder visibility and message display. The roadmap adds that timelines may change as the project learns and iterates. So the web client is real, but it is a first step and not a finished Gmail replacement.
Other items on the roadmap:
- Shipped: Multifactor authentication via TOTP or a similar method, in June 2026. Thunderbird staff said in a June comment that MFA would initially use authenticator apps, and that email-based codes were not decided.
- Shipped: A spam-filtering change. The filtering had been so aggressive that many emails unintentionally landed in the spam folder, and it was changed to improve this.
- Planned: An import feature for email, contacts and calendar data, aimed at making Thundermail the user's primary inbox. This matters if you are thinking of moving off an existing mailbox.
- Planned: Better integration of the Thundermail add-on into Thunderbird desktop, through the system add-on or account add-on mechanism.
One more detail from the project's staff in the June comments: Thundermail is built on the open-source Stalwart mail server and includes a calendar by default. A user who wanted a version without the calendar was told that likely isn't possible. The same staff said each account has a single inbox. Messages from aliases and custom domains all land there.
When does it launch?
The Register asked Thunderbird for a launch date and had no answer at publication. It notes the organisation previously said a full launch was expected sometime in 2026. I found no firm public date in the sources I reviewed. The roadmap's unfinished items, import tools and the experimental webmail, suggest a general launch may still be some way off. That is my reading, not a Thunderbird statement.
What Windows and IT readers should take from it
- Desktop users: Thundermail works with standard clients, so you can try it from Thunderbird or another mail app without being forced into a browser. Thunderbird says it is sticking to open standards.
- Windows and Microsoft shops: The Register notes Thunderbird gained support for Microsoft Exchange late last year. That fits a wider push to make it a credible alternative for people who live in Outlook. Thundermail is a separate, consumer-oriented hosted service, not an Exchange replacement for enterprises.
- Cost-conscious users: Free ad-supported mailboxes remain free. The Register's point is that Gmail and Outlook.com serve ads alongside messages, while Thundermail charges instead.
- Anyone considering migration: Wait for the import tools and final pricing. Early access is a place to test, not a place to move your only mailbox.
The bottom line is that Thundermail is real and usable by invited testers. It is still an early-access product with a basic webmail client and no confirmed public launch date.