Before Demo Day: The Part of Building People Don’t Usually See
Demo Day offers a polished snapshot of a venture: a clear story, a practiced pitch, and a next step that can seem obvious. What audiences do not see is how much can change before a founder reaches the stage.
During the first month of Tsai CITY’s Summer Fellowship, student founders work alongside one another on campus, testing assumptions, processing difficult feedback, and deciding what deserves their attention. Some refine their original plans, while others realize the evidence is leading them toward something entirely different.
“The early weeks are not about proving that you already have the right answer,” says Sade Owoye, director of entrepreneurship at Tsai CITY. “They are about asking better questions, testing assumptions, and allowing what you learn to shape what comes next.”
Building in community
Fellows move between workshops, mentor meetings, customer discovery, product development, and dedicated building time. Outside the formal schedule, they compare notes, practice explaining their ventures to one another, and talk honestly about what they still have not figured out.
Building a venture can be isolating. The fellowship creates a community of peers, experts, and advisors who offer guidance and accountability while navigating similar challenges.
“Building alongside fellows whose execution matches their extraordinary ambition has expanded my sense of what is possible,” says Safari Strives founder Elie Imani (GRD ’27). “Their vision, discipline, and speed have pushed me to think bigger while executing more seriously.”
Deciding what matters now
For Paris Mielke (YC ’29), founder of Tangram, the fellowship has helped bring greater focus to the decisions that come with growing a venture.
Tangram is an AI-powered platform that allows users to build and operate online marketplaces without months of custom development. As the venture grows, Paris is balancing requests from existing customers with the need to reach new ones.
“Building a great product is one challenge, but startups are defined by their ability to scale,” Paris says.
During the remote portion of the fellowship, Tangram is developing and distributing content based on prospective customers’ questions. The venture combines conversion data with customer interviews to understand which messages and channels are most effective at reaching potential customers.
“The challenge isn’t identifying everything that deserves attention,” she says. “It’s choosing the right thing to work on today and turning that choice into measurable progress.”
When the evidence changes the idea
Noah Safar (YC ’27) entered the fellowship building Aiden AI, an AI chief of staff for email and calendar. Although people enjoyed using the product, similar features were becoming standard within established platforms, prompting Noah to reconsider the venture’s long-term potential.
“The real thing I had to learn was how to tell a cool product apart from a venture-scalable one,” Noah says. “What matters is whether there’s a defensible wedge and a market big enough that winning it is worth a decade.”
That realization led him back to a problem he had encountered while studying medicine in Germany and working in a hospital: the time and revenue healthcare providers lose navigating insurance denials. Noah made a full pivot, leaving Aiden behind to develop Overturn, an end-to-end workflow for appealing those denials.
Conversations with healthcare professionals helped shape the product. After observing a biller manually navigate time-sensitive denials, Noah shipped two new features that same week.
“I came into the fellowship thinking my job was to keep building,” Noah says. “The part I had to learn was to step back, talk to people who’ve spent their careers in the field, and let what they told me change the plan. That was my step from a builder to a founder.”
Two healthcare practices have now committed to early pilots designed to test whether Overturn can recover denied revenue more efficiently.
Knowing which feedback to follow
Mentors, speakers, and advisors help founders see the questions they may not be asking yet. That could mean examining whether customers experience a problem as urgently as expected, how they currently address it and what the problem costs them.
“The most useful customer discovery feedback does not always tell you exactly what to do,” says Margaret Cartiera, venture advisor and lead for strategy and new initiatives at Tsai CITY. “Often, it reveals the gap between what you believe and what your customer needs and values.”
Those conversations can also help founders determine how significantly their plans need to change. If customers confirm that the problem matters but the proposed solution doesn’t resonate, the venture may need refinement. If founders discover they are addressing the wrong problem or speaking with the wrong customer, a larger pivot may be necessary.
The mentor’s role is not to make that decision for them. Margaret encourages founders to enter mentoring conversations ready to expand their thinking and challenge assumptions, so they leave with a fresh perspective and clear next steps.
For Elie that meant translating Safari Strives’ vision into a focused plan for a 16-week accelerator in Rubavu, Rwanda. Safari Strives will begin with an intentionally small cohort of four entrepreneurs, measuring each business’s progress against defined goals.
“As a solo founder, every major decision eventually comes back to you,” Elie says. “The fellowship has pushed me to turn ambition into clear priorities, identify where I genuinely need support, and focus on proving what works before trying to scale it.”
Taking the work beyond Tsai CITY
After a month on campus, the fellowship transitions to a remote format. Without the natural check-ins that happen when everyone shares a room, founders must establish their own routines, protect time for the work, and maintain momentum.
They take with them the relationships formed on campus and the habits developed through repeated practice.
By Demo Day, audiences will see each founder’s progress and direction. What they will not see are the discarded ideas, difficult conversations, and moments of reconsideration.
Those moments may never make it into the final pitch, but they are often where the real work happens.