Building Zethko: Our Journey From Idea to Launch

Every startup has an origin story. Ours began with a simple frustration: despite having hundreds of professional contacts, we constantly found ourselves forgetting important details about the people we knew.

Here is the story of how Zethko came to be.

The Spark

The idea for Zethko came during a particularly embarrassing moment. Our founder was at a conference, running into someone they had met multiple times before. They could not remember where they had met, what they had discussed, or even what company the person worked for.

After awkwardly fumbling through the conversation, they spent the train ride home thinking: why is it so hard to remember the people in our lives?

We have apps that remember our passwords, track our fitness, and manage our finances. Why do not we have something that helps us remember our relationships?

Early Exploration

The first few months were spent researching and understanding the problem. We interviewed over 100 professionals about how they manage their relationships. Some key insights emerged:

The Tool Fragmentation Problem

People's relationship information was scattered across email, LinkedIn, WhatsApp, notes apps, and their own memory. No single place had the complete picture.

The Context Problem

Before important meetings, people would frantically search through emails trying to remember what they had discussed previously. This preparation was stressful and often incomplete.

The Follow-Up Problem

Most people had good intentions about staying in touch but lacked a system to make it happen consistently.

These insights shaped our product direction: we needed to create a unified relationship layer that could sit on top of existing tools and provide intelligent, actionable insights.

Building the First Version

With the problem clearly defined, we started building. Our initial team was small - just three people working out of a co-working space in London.

The first version was incredibly basic: a Chrome extension that would show you information about the person you were emailing. It pulled data from LinkedIn, your previous emails, and any notes you had made.

We called it "Relationship Copilot" and shared it with a small group of beta testers.

The feedback was immediate and enthusiastic. People loved having context at their fingertips. But they wanted more:

"Can it remind me to follow up with people?" "Can it work with my calendar too?" "Can it suggest what to talk about?"

We realised we had only scratched the surface of what was possible.

The AI Pivot

About six months into development, we made a crucial decision: to put AI at the centre of our product.

Large language models had reached a point where they could genuinely understand the nuances of human communication. They could summarise long email threads, identify the sentiment of interactions, and even suggest personalised follow-up messages.

This was not just an incremental improvement - it was a fundamental shift in what was possible.

We spent the next several months rebuilding our core infrastructure around AI. This meant: - Building natural language processing pipelines to understand communications - Training models to identify relationship patterns and signals - Developing a recommendation engine for follow-up timing and content

It was the hardest technical challenge we had ever tackled, but the results were worth it.

Privacy Challenges

Building with AI created immediate privacy concerns. Our users were trusting us with their most sensitive communications. How could we process this data intelligently while maintaining privacy?

We developed several key innovations: - On-device processing for sensitive analysis - Differential privacy techniques to aggregate insights without exposing individual data - User-controlled encryption keys - Granular permission systems

Privacy became a competitive advantage, not just an obligation.

The Beta Launch

In January 2025, we launched our private beta with 500 users. The response exceeded our expectations.

Within the first month: - Average daily active usage reached 23 minutes - 87% of users connected at least two data sources - Net Promoter Score hit 72

More importantly, we started hearing stories that validated our mission:

"I reconnected with a mentor I had lost touch with. Zethko reminded me it had been six months since we spoke."

"Before a crucial investor meeting, Zethko briefed me on everything we had discussed in previous meetings. I felt so prepared."

"For the first time, I feel like I am actually maintaining my network instead of just accumulating contacts."

Lessons Learned

Looking back, several key lessons stand out:

Start with a Narrow Use Case

Our initial focus on email context was narrow, but it let us perfect the core experience before expanding. Trying to do everything at once would have resulted in doing nothing well.

Privacy is a Feature

In a world of data breaches and surveillance capitalism, strong privacy practices are a genuine differentiator. Users notice and appreciate when you respect their data.

AI is a Tool, Not Magic

AI capabilities are impressive, but they are most powerful when they augment human judgment rather than replace it. Our best features keep users in control while reducing cognitive load.

Listen to Users, But Also Watch Them

What users say they want and what they actually use can be different. We learned to balance feedback with behavioural data.

Build for the Long Term

Some of our best decisions - like investing heavily in privacy infrastructure - had no short-term payoff but positioned us well for the future.

What Comes Next

We are just getting started. Our roadmap includes: - Expanded integrations with more communication platforms - Team features for organisations that want to build relationship intelligence together - Advanced AI capabilities for even smarter insights - Mobile experiences that work wherever you are

But more than any specific feature, we are committed to our core mission: helping people build and maintain meaningful relationships in an increasingly connected world.

Thank you for being part of this journey. Whether you have been with us since day one or are just discovering Zethko now, we are grateful for your trust and support.

Here is to building something great together.