Creating DoublOne: The Technical and Design Challenges of Building a Privacy-First Email Client

When I first conceived DoublOne, I had a clear vision:

an email client that looked and felt as effortless as a chat app but without sacrificing privacy.

The idea grew out of frustration with traditional email interfaces—rigid, impersonal, and dated. And then, the privacy issue.

Emails have increasingly become targets for data exploitation, and I was driven to build something that put the user’s control and privacy at the heart of its design.         

This is my story as the founder of DoublOne, the journey through technical and design challenges, and the lessons learned in building a product that respects both user experience and privacy.

The Vision Behind DoublOne

DoublOne started with a simple but challenging idea: bridge the gap between email and chat while making sure privacy remained central.

I’d always believed that email was due for a change—an evolution, if you will. Most email clients treat messages as standalone items, each interaction separate and formal, which is the opposite of how most people communicate today.

We want to get straight to the point, back-and-forth, fluid, like we do with chat. But the existing platforms weren’t designed with that kind of interaction in mind.

Privacy, on the other hand, has always been a personal commitment.

I’ve spent years advocating for privacy-focused digital tools, and I wanted DoublOne to reflect this deeply. Email is still a vital tool, yet so few of the popular clients genuinely protect our data.

For me, this was the driving force—the conviction that we could create something more respectful, more human, and much more private.

As we began designing DoublOne, I knew we had a long road ahead, filled with technical and design hurdles. But I also knew that if we got it right, DoublOne could be more than just another email client. It could be a game-changer in the digital privacy landscape.

Technical Challenges and Solutions

Building DoublOne meant facing a range of complex technical issues head-on. Every decision had to balance functionality, ease of use, and privacy.

Optimizing the Chat Interface for Email

One of the first—and most difficult—challenges was merging the structured, formal nature of email with the organic, quick-paced feel of chat. Emails often include more text, attachments, and a structured format, while chat thrives on brevity.

To make this transition seamless, we had to adjust both design and functionality. For example, email threads were tricky.

Traditional email clients display them linearly, but to create a chat-like experience, we had to manage email threading so that it would resemble the flow of a conversation, almost in real-time. MIME parsing, a technical requirement to handle diverse content types in emails, added another layer of complexity.

Ensuring that attachments, HTML content, and inline replies all appeared naturally in a chat view was a massive challenge.

We developed custom parsers and handling systems to break down each email’s content and format it like chat without losing its original structure.

Implementing Privacy-First Data Handling

Privacy is at the core of DoublOne.

From the outset, I was determined that:

we wouldn’t store user emails on our servers.

This decision wasn’t just a principle; it was a technical commitment that had far-reaching implications for performance and speed.

Instead of storing emails, we opted for an on-demand fetching approach.

Emails are only retrieved as needed, which drastically reduces the need for data storage.

However, this came with its own set of challenges, particularly with latency.

The immediate concern was performance—how do we make fetching seamless without creating a laggy experience?

We explored various caching strategies, balancing between holding data temporarily for quick access and ensuring it wasn’t stored long-term.

In the end, we implemented a hybrid approach, where critical data is cached locally with end-to-end encryption.

Handling Email Storage and Syncing

Email sync traditionally requires substantial server-side resources, which conflicts with our minimal server interaction philosophy. DoublOne syncs directly with the user’s email provider using protocols like IMAP, but achieving this without a typical server-mediated storage solution meant building a new sync engine that could handle data locally and privately.

We engineered a decentralized sync approach, ensuring data accuracy and reliability by focusing on local storage and on-the-fly syncing. This means that emails sync as you access them, a process optimized for speed without compromising privacy. Each email is encrypted, stored locally, and removed if not accessed for a specific duration.

Integration with Diverse Email Providers

Integrating with various email protocols like IMAP was a whole other adventure. Each email provider has its quirks, different interpretations of standards, and unique limitations. Working with multiple formats—from plain text to complex HTML emails—required adaptable parsing and rendering solutions. One key decision was to build a flexible abstraction layer that could interpret and display emails regardless of their provider-specific format, so DoublOne could work consistently across platforms.

Design and User Experience (UX) Challenges

Building a privacy-first product isn’t enough—it also has to be intuitive and engaging. As someone with a technical background, translating that into a smooth, user-friendly experience was a new journey.

Crafting a Minimalist Yet Feature-Rich Interface

I’ve always valued simplicity in design, but designing an interface that was minimal yet functional presented some fascinating challenges. We didn’t want to overwhelm users with features, but we knew we needed to incorporate enough functionality to make DoublOne stand out.

After extensive user research and testing, we implemented command shortcuts, making the app feel responsive and intuitive. We designed the interface to allow for easy access to common actions like replying, archiving, or marking emails as unread. Instead of complex menus, we introduced a few well-placed icons and contextual menus that keep things simple yet powerful.

Ensuring an Intuitive User Journey

One of my key goals was to make DoublOne feel familiar to users, whether they came from traditional email clients or messaging apps. The challenge lay in ensuring the transition was smooth. To tackle this, we designed an onboarding process that walked users through key features without overwhelming them. We tested this repeatedly to make sure it felt natural and paced, even for those who aren’t tech-savvy.

Maintaining Consistency Across Platforms

Building a consistent experience across mobile and desktop are essential for DoublOne' s success. In today’s multi-device world, users expect their apps to work seamlessly wherever they go. This required creating a responsive design that adapted gracefully to different screen sizes and resolutions without sacrificing functionality.

We paid particular attention to interaction design on mobile, optimizing touch gestures, and ensuring each tap or swipe felt intuitive. Responsive layouts, adaptive icons, and thoughtful navigation were all part of this process. The result was a unified experience across platforms that looked and worked just as well on mobile as it did on desktop.

Accessibility and Usability

One of the core values of DoublOne is inclusivity. We wanted to ensure DoublOne was accessible to everyone, including those with disabilities.

This involved implementing keyboard shortcuts, ensuring screen reader compatibility, and fine-tuning color contrast for readability.

Designing with accessibility in mind was an ongoing process, but it was worth it to create a product that truly anyone could use.

Key Takeaways and Lessons Learned

Looking back, building DoublOne has been a transformative journey.

I learned so much about balancing privacy and performance, a trade-off that required careful consideration at every stage.

Each technical solution often meant a design compromise, but over time, we found a balance that works.

One of my biggest takeaways is the importance of user-centered design. Every feature, every interface decision, was shaped by feedback from our users, which helped us build an experience that felt personal and responsive. My advice to anyone working on privacy-focused products is this: design with your users’ needs front and center, and never lose sight of the privacy commitment.

A huge thank you to all our beta users for your incredible support and invaluable feedback—you’re helping us grow in ways we truly appreciate, more than you can imagine!

For a sneak peek at our upcoming roadmap, or to share and upvote feature requests, visit feedback.doubl.one.

Closing Thoughts

DoublOne is still evolving, but I’m incredibly happy about the direction in which we're headed.

It’s a product that challenges the notion that users have to compromise privacy for convenience.

Looking forward, we’re working on new features, some of which will make the DoublOne experience even more seamless and intuitive.

Our mission remains the same: to provide a private, user-friendly email experience that feels as natural as chatting.

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