Thunderbird Pro and Thundermail: Mozilla renews its commitment to email

Mozilla has announced a profound transformation of its traditional Thunderbird email client.. Taking advantage of its loyal user base and the resurgence of interest in open source software, it has introduced Thundermail and the service suite Thunderbird ProThe goal isn't simply to update the tool, but to make it a real alternative to platforms like Gmail or Microsoft 365, focusing on privacy, transparency, and user control.

Thundermail was born as its own email service, while Thunderbird Pro serves as an umbrella for several complementary productivity-oriented tools, all built on open source principles. These changes come at a time when digital privacy concerns are gaining traction with Big Tech. Mozilla seeks to offer an option that respects user data without sacrificing key functionality.

Thundermail: Mozilla's new email service

Thundermail is an email service based on the Stalwart technology stack., an open-source infrastructure that aims to modernize email with protocols like JMAP, designed as successors to IMAP. Users will be able to access addresses like @thundermail.com o @tb.pro, and it's anticipated they'll be able to use custom domains in the future. This service aims to match the advantages of Gmail, but without compromising privacy.

The structure of Thundermail has been designed to offer control options over the storage of messages, with servers initially hosted in Europe and the ability, in the future, to choose the jurisdiction in which data is stored. The idea is to offer full message encryption, although key management mechanisms and the specific operation of encryption between users are still being evaluated.

One of the distinctive features is that Thundermail will not include ads or trackers., and the company pledges not to exploit the email content for commercial purposes. The intention is to provide a complete and ethically and technically respectful experience, something Mozilla has long owed its community.

Thunderbird Pro: A suite of tools for productivity and collaboration

Thunderbird Pro is made up of several services designed to facilitate daily work from a free and secure perspective.Mozilla has started with four key tools that mark the starting point of this new ecosystem.

• Thunderbird Appointment: A tool for easily scheduling appointments. Send a link to your contacts so they can choose an available slot on your calendar. It aims to replicate popular options like Calendly, but with open control and even the option to self-host.
• Thunderbird Send: An evolution of the now-defunct Firefox Send. It allows you to send large files securely, encrypted and directly. Useful when traditional email doesn't support large attachments.
• Thunderbird Assist: A intelligent assistant based on IA, in collaboration with Flower AI. Its main feature is that it can operate locally if the device allows it, or use encrypted remote processing. In all cases, its use will be optional and transparent to the user.
• Thundermail: already mentioned, it is the core of this communication platform.

All these tools will initially be available free of charge to active project collaborators.The rest of the users will be able to access it through a subscription, which Mozilla hopes to make sustainable without relying on ads or data sales. Limited free versions (for example, less storage capacity in Send or fewer addresses in Thundermail) are planned for the future.

A model based on community and transparency

All developments in Thunderbird Pro are intended to be replicable and auditable by the community.Mozilla has open-sourced part of the code and plans to release the rest in the coming months, ensuring that the services can be self-managed by advanced users or businesses that want to maintain complete control over their data.

This shift towards own services comes after several years of economic and technical recovery of the Thunderbird project. Between 2021 and 2023, user donations increased from $2,8 million to $8,6 million, allowing us to expand our team, modernize our codebase, and release versions for Android (and coming soon) iOS).

The strategy is completed with a new continuous development modelStarting in February 2025, a new version of Thunderbird is released every month, allowing for faster implementation of improvements and fixes. This system also makes it easier to implement new features when they're ready, without waiting for major annual updates.

Privacy, open source and user control as central pillars

Mozilla insists that the Thunderbird Pro and Thundermail proposal is more ethical than technical.In an environment where many free services are funded by exploiting personal data, offering a non-data-mining alternative is a statement of intent. According to Ryan Sipes, product manager, it's a way to address years of absence in the web services industry.

The community will be able to deploy its own instances of Appointment or Send, and participate in the discussion about how to implement end-to-end encryption, key management, and other sensitive issues. Transparency will be provided at every step of the process, and Mozilla is committed to keeping control in the hands of users.

Even the testing infrastructure is already running on servers located in the European Union., which guarantees greater legal protection under GDPR regulations and allows for a future with different hosting regions depending on the user's preferred jurisdiction.

The sustainable approach behind the freemium model

To sustain these services without relying on external funding, Mozilla has opted for a voluntary payment model.Users who wish to do so will be able to access advanced versions of each tool through a subscription, while active project contributors will continue to have full access for free.

The idea is not to monetize privacy, but to maintain ethical services in the long term without resorting to advertising or invasive models.As Mozilla explains, storing and sharing large files or maintaining email services requires expensive infrastructure. Therefore, those who use these tools the most will assume part of the cost, allowing basic, free versions to be maintained in parallel.

The entire Thunderbird ecosystem seeks to be a benchmark for how useful technology can be made without compromising the user.With these new additions, the platform is positioning itself as a viable, transparent, and respectful alternative to the tech giants in the email and productivity space.

Thunderbird Pro and Thundermail pave the way for a fairer and more transparent digital ecosystem. Thanks to an active community, sustained investment through donations, and a new approach that goes beyond the mere email client, Mozilla has managed to position the privacy and the FOSS at the center of the digital experience. It remains to be seen how its adoption evolves and whether it manages to recover some of the lost users, but the truth is that, this time, the proposal is backed by a solid strategy and a careful technical execution.