Semih Janssen

Why this persona fits the audience

Leads a 4-person Amsterdam team building a developer tool with org accounts and seat-based billing. The app currently uses open-source auth, Stripe, and a homegrown usage ledger in Postgres; he reviews webhook failures and access flags during releases.

• Age: 35
• Location: Amsterdam, Netherlands
• Occupation: Founder and product engineer
• Income: €70k-€130k personal income
• Education: Master's in computer science
• Company size: 4
• Years in role: 5

“The real satisfaction comes from building something robust that others can rely on, piece by carefully crafted piece.”

Semih Janssen, 35, is a Dutch founder and product engineer based in Amsterdam, driven by a deep-seated belief in technical rigor and the power of open-source software. He earned his Master's in Computer Science from the University of Amsterdam, where his thesis focused on distributed database consistency models, a topic that continues to inform his work. After a few years at a larger tech firm, he felt constrained by corporate bureaucracy and the slow pace of innovation, leading him to co-found his current venture five years ago. His company, a lean four-person operation, is dedicated to building sophisticated developer tools, specifically focusing on unifying authentication, organizational management, and usage-based billing for SaaS platforms. Semih is the primary architect and engineer, meticulously crafting solutions that prioritize maintainability and long-term stability. Their current stack is a testament to this philosophy: leveraging open-source authentication libraries, Stripe for payments, and a custom-built usage ledger meticulously managed within a PostgreSQL database. He views ownership not just as intellectual property, but as the responsibility for the entire lifecycle of the software they ship. This manifests in his hands-on approach, where he personally reviews critical operational metrics like webhook failures and access flags during every release. His personal income hovers between €70k-€130k, reflecting the lean startup reality, but he prioritizes reinvesting profits back into the company's infrastructure and talent. Semih is deeply committed to the principles of steady execution, believing that consistent, high-quality development is the bedrock of a successful, sustainable business. He sees his role as building not just a product, but a reliable foundation for other developers to build upon, a philosophy that guides every architectural decision he makes.

Background & daily life

A day in their life

Semih's typical weekday starts around 8:30 AM after a cycle to his home office. He begins by reviewing overnight monitoring alerts, checking for any critical webhook failures or access flag issues from the previous release. After a quick stand-up with his team, he dives into coding for 2-3 hours, focusing on a new feature for their org accounts module. Lunch is usually a simple meal prepared at home. The afternoon is split between code reviews, architectural discussions with his team, and deep dives into Postgres performance tuning. He might spend an hour investigating a subtle bug reported by a user. He wraps up around 6:30 PM, often with a final check of the deployment pipeline status before cycling home.

Lifestyle

Semih lives in a moderately sized apartment in Amsterdam's Oud-West district with his partner, a graphic designer. Their lifestyle is comfortable but not extravagant, prioritizing experiences and quality over material possessions. He cycles everywhere, even in less-than-ideal weather. Weekends often involve exploring local markets, trying new recipes, or attending small tech meetups. He's conscious about his health, aiming for regular runs along the canals, and manages finances with a focus on long-term stability and reinvesting in his company. Social life is a mix of close friends and industry contacts, often centered around shared technical interests.

Work life

As founder and lead engineer, Semih's workdays are a blend of deep technical problem-solving and strategic decision-making. He spends significant time architecting new features, optimizing database queries in their Postgres instance, and ensuring the reliability of their homegrown usage ledger. He's deeply involved in code reviews for his small team of three engineers, focusing on maintainability and adherence to their technical standards. The pressure comes from balancing rapid development with the need for robust, scalable infrastructure, especially as they onboard more organizations. He often finds himself debugging complex webhook interactions or performance bottlenecks late into the evening.

Relationships

Semih's closest relationships are with his partner, who provides a grounding influence and a different perspective on creative problem-solving, and his small, tight-knit engineering team. He trusts their technical judgment implicitly. His professional network consists mainly of fellow indie founders and open-source contributors he interacts with online and at occasional conferences, who serve as a sounding board for technical and business challenges.

How they decide

Semih is a research-heavy and analytical decision-maker. He thoroughly investigates technical options, weighing pros and cons based on long-term maintainability, performance, and alignment with their open-source philosophy. He prefers to understand the underlying mechanisms before committing to a path, often prototyping or running small experiments. While he values peer input from trusted colleagues, the final decision rests on his own rigorous evaluation.

How they sound

Speaks with a measured, calm cadence, often pausing to formulate precise technical explanations. His Dutch accent is subtle but present. He tends to avoid hyperbole and buzzwords, preferring direct, factual language. When discussing technical challenges, he uses specific terminology related to systems architecture and database operations. He might occasionally use mild Dutch interjections like 'nou ja' or 'precies' when agreeing or emphasizing a point.