After more than 15 years in the tech industry, leading teams in startups and scaleups, I have gone through all kinds of challenges: technical, human, strategic, and personal. Today I look back and see not only successes, but also a long list of mistakes. Mistakes that formed me, shaped me, and taught me more than any course, mentoring, or book.
I want to share some of these learnings with the hope that they can help you, whether you are starting your path as a technical leader or in the middle of your career evolution. Sometimes, experience hurts. But it hurts less when shared.
1. Stopping networking
One of the most serious —and perhaps least obvious— mistakes was abandoning the habit of building and nurturing my professional network.
When I started taking on leadership roles, especially as an Engineering Manager and then CTO, I focused so much on the teams' internal problems that I neglected the external ones. I stopped attending meetups, became absent from industry conferences, and completely suspended mentoring and coaching activities.
The excuse was always the same: I don't have time.
But there is an even more complex aspect: I underestimated how much it costs to rebuild a network when you move to a new country. I lived this experience first in Portugal and then in Spain, where I have resided for the last five years. Arriving in a new country, no matter how much cultural affinity there is, means starting almost from scratch. Your local contacts are not there. Your reputation does not precede you. Your name does not open doors.
In addition, the ecosystem is different. The key figures change. The dynamics, the channels, even the language used to talk about technology and business varies. I thought my previous experience would be enough to integrate easily. I was wrong.
Rebuilding my network required humility, time, and active effort: attending events, asking for introductions, participating in local communities, and offering myself as a mentor without expecting anything in return. It was slow, but deeply rewarding, and I am still at it.
Today I understand that networking is not an 'extra' activity. It is a continuous professional responsibility, especially in leadership roles where connection with the ecosystem can define access to talent, partners, opportunities, and fresh ideas.
2. Focusing exclusively on people management
Like many technical leaders, I went through the transition from being hands-on to being a people manager. At first, I completely immersed myself in this new dimension: processes, coaching, OKRs, strategic planning, career development, organizational culture.
And yes, I did it with passion. I like working with people. I like to see someone I mentored grow. But I made a subtle mistake: I moved too far away from the technical aspect. I stopped doing code reviews, participating in architecture decisions, or staying in touch with real technological challenges.
This generated a disconnect. Not only for me, as I started to feel that I was losing part of what motivated me, but also for the teams, who expected a technical reference from me, not just a coach.
A little over 4 years ago, I joined early-stage startups or those focused on modernizing and scaling their technological services. I sought environments that would allow me to lead people, but at the same time write code and contribute alongside the teams. In fact, at Venturest, I went back to the core basics, building practically the entire technology platform by myself, from the back-end to the front-end, adopting serverless, AWS, continuous integration and continuous deployment, ECS clusters, and a host of other tools.
I found balance again by setting aside weekly time for technical activities. Not to micromanage, but to stay close: understanding the challenges, reviewing critical decisions, and being part of the technical debate. Technical leadership does not require you to be the best programmer, but it does require you to maintain credibility and understanding of the stack, the product, and the business.
3. Underestimating the complexity of moving to another country
Moving sounds glamorous: new opportunities, new challenges, personal growth. But the reality is tougher. Moving to another country, even within Europe, involves a deep adaptation process.
When I moved to Spain, I wasn't just changing my house or job. I was reshaping my social network, my routines, my emotional environment. Even small details —like opening a bank account, understanding healthcare systems, or knowing where to buy groceries— became daily obstacles.
Add to that the cultural weight. Although we have a language very similar to Portuguese, social and work norms are different. The way of leading, giving feedback, and relating professionally varies. And it is not always easy to navigate those differences without feeling isolated or frustrated.
Today, when someone tells me they are evaluating moving for a job offer, my advice is clear: prepare yourself emotionally as much as professionally. It is not just a change of scenery. It is a change of identity.
4. Learning Spanish and stopping speaking English
This mistake might seem trivial, but it had unexpected consequences. When I arrived in Spain, I decided to commit to the local language. It made sense: I wanted to integrate, lead better, and understand the cultural nuances.
The problem was that in the process, I set English aside. I isolated myself —without realizing it— from many global conversations, international collaboration opportunities, and access to technical communities that communicate mainly in English.
Furthermore, learning a new language, without having a natural ease for it, demanded a lot of energy. Energy that, for months, I could not dedicate to my technical or leadership development.
Today I am proud of speaking Spanish fluently. But I also understood that, in technology, English is not optional. It is not about giving up one language or the other, but about building the ability to operate in both worlds. That duality is part of modern work.
5. Not sharing my learnings through content
For years, I limited myself to the closed circle of my company. I thought that sharing learnings publicly was for 'gurus' or influencers. That I didn't have time, that it wasn't my thing, that others already did it better.
That silence cost me. I lost visibility, yes, but more importantly: I lost opportunities for reflection. Because when writing, teaching, or speaking in public, you organize your ideas, deepen your learnings, and generate valuable conversations.
Since I started sharing more —through articles like this one, talks, open mentoring— my career has been enriched. I connected with colleagues from other industries, received unexpected feedback, and even job and collaboration opportunities arose.
You don't need to have all the answers. It's enough to have something genuine to tell.
6. Ignoring that the Startup environment is very volatile
Working in startups is exciting. The cycles are fast, the impact is tangible, the learning curve is brutal. But it is also unstable ground.
For a long time, I assumed that with enough talent and effort, we could 'tame' that instability. That once the product was launched, or the market validated, calm would come. It never arrives.
Volatility is part of the game: changes in strategy, cutbacks, pivots, acquisitions, team turnover. When you cling to the illusion of stability, the hit is harder.
Today, I lead with that awareness. We design more resilient structures, more adaptable processes, and above all, we cultivate a culture that embraces change as part of the journey.
7. Delaying my dream of entrepreneurship for too long
For years, I helped others build their dreams. I was at the forefront of teams that launched innovative products, scaled platforms, and overcame crises. But I postponed my own ambition of entrepreneurship.
There was always a reason: bad timing, fear of risk, comfort. I told myself I was already 'intrapreneurial' within my role, but I knew it wasn't the same.
When I finally joined the dream of VENTUREST, I understood everything that had been holding me back. Entrepreneurship is not just about launching a company. It is an act of self-definition. It is saying: 'this is what I want to build in the world, and this is how I want to do it'.
I remember a 1:1 I had with Bruno Ghisi, CTO of RD Station, in 2018, where I shared my goal of training myself beforehand to start a business in the future. Ghisi told me something that stayed with me: in the end, one will never be completely prepared for it. There is no line indicating 'from now on you are ready to be an entrepreneur.' Entrepreneurship is about dealing with ambiguity, uncertainty, and anxiety. It is a continuous learning and training journey.
Honestly, it's not an easy task; a whole new universe of learnings and feelings has opened up for me, dealing with partners, having people under your charge, all that is another level of complexity and responsibility.
I wish I had started earlier. But I also know that each previous step prepared me to do it with more clarity and maturity.
8. Neglecting my health and absorbing every problem
This is perhaps the most human mistake. In my eagerness to be a good leader, I became the 'emotional container' for all the team's problems. I listened, resolved, mediated... and absorbed.
For years, I carried others' stress as if it were my own. I stopped exercising, ignored warning signs of exhaustion, and disconnected from habits that did me good.
Until my body took its toll. And I understood that self-care is not selfishness, it is responsibility. I am still in a learning process, prioritizing rest, setting clear limits for myself, and delegating without guilt. And, paradoxically, that is making me a better leader.
Final reflection
Being a CTO or Engineering Manager is not just about mastering technology. It is about leading in uncertainty, adapting to new contexts, and learning daily. Many of these mistakes were not obvious at the time. Only with distance —and humility— was I able to see their impact.
I share this because I believe that talking about mistakes humanizes us, brings us closer, and makes us grow. And because, perhaps, someone starting this journey can save themselves a few stumbles if they read these words in time.
