From Coding at 10 to Silicon Valley Titan: The Untold Secrets I Use to Spot Startups That Explode—And Why Most Investors Get It Dead Wrong

In the late 1980s, 10-year-old Alex Roetter sat in front of an Apple IIe computer with nothing more than a programming manual and a love for video games. Without formal instruction, he taught himself to code, creating a model rocket simulator and a rudimentary version of Pong — early signs of a builder’s instinct that would shape his career.

That curiosity carried him from Stanford’s undergraduate and graduate computer science programs to early roles at Google, to leading engineering at Twitter, now X, and eventually into venture capital as a general partner at Moxxie Ventures. After more than a decade as an angel investor, Roetter has developed a clear perspective on what makes a startup worth betting on.

The following as-told-to interview has been edited for clarity and concision. 

Early beginnings

Apple made a computer called the Apple IIe, and my dad brought one home. Those computers came with a BASIC programming manual in the box, which is funny to think about now — imagine buying a laptop at the Apple Store that came with a programming manual.

I sat down, read the manual and started programming. Growing up, we had strict limits on “video game time,” but “educational time” on the computer was unlimited. That was a loophole for me. I could sit there and teach myself to program and build random things for as long as I wanted, and I loved it.

Career milestones

I never had a master plan. Each step was thoughtful, but there was no grand design. When I went to college, I didn’t know what to major in. I thought I might do biology. I remember flipping through the course catalog and realizing there were so many computer science classes I wanted to take that if I just took everything that looked interesting, I’d satisfy the major requirements. That’s how I ended up majoring in and then doing graduate work in computer science.

When I graduated, it was the first dot-com boom. I worked at a couple of startups — some didn’t work. Then I joined Google when it was still a startup, which obviously did work. Google was excellent at large-scale systems engineering and had some of the best computer scientists in the world. Being a 22-year-old and seeing how high-quality engineering at scale works was fundamental for me.

Later, after a couple more startups, I joined Twitter somewhat randomly. I had met someone online who had written open source software and worked there. When I joined, they hired me into engineering and told me to “walk around and pick something to work on.” There was no hiring plan for specific teams.

At Google, I had worked a lot on the ad system, so I understood computational advertising. When I joined Twitter, they had no revenue, and most people weren’t worried about it. A few people were, but many thought making money was “corporate” and uncool. That’s an interesting attitude for a company to have.

I ended up starting the ads team with some others. We built the first ad server and the revenue engine that grew to about $2.5 billion a year in revenue. I ran that team, and after Twitter went public, the CEO asked me to take over engineering for the whole company.

That job was fascinating, but being an officer of a public company isn’t my idea of fun. You do amazing things and learn a lot, and it can be very lucrative, but there’s also a lot of big-company process that isn’t for me. So I eventually left.

Becoming an angel investor

I have a background in aviation and have been flying airplanes for almost 20 years. I got the chance to run an eVTOL startup — an electric vertical takeoff and landing “flying car” company. It was too cool not to do. I couldn’t imagine being 80, looking back, and thinking, I wish I hadn’t worked on flying cars. It’s a very challenging business, and I expected that, but I got to work on an awesome project with very smart people.

Along the way, I started angel investing. I’d meet great engineers and product people and try to hire the best ones into Twitter or wherever I was. Sometimes they were working on something great that couldn’t possibly be a Twitter project, but I still wanted to help, learn from them and stay close to what they were building. Angel investing was a way to do that. Over time, that activity grew.

A former colleague from Twitter, Katie Stanton — now my partner at Moxxie Ventures — had started a fund and was running it solo while I was working on flying cars. I helped her on the side with diligence, bringing in deals and co-investing personally. The timing worked out: She wanted to raise a larger fund right when I was finishing the flying car role. We teamed up, and we’ve been doing Moxxie full-time since.

Focus of Moxxie Ventures

We’ve invested in dozens of companies. Most are software and AI startups, but we’re quite generalist. We’ve backed carbon removal, “metal as a fuel” companies, vertical AI applications like Spellbook, which is a legal AI company, and several healthcare “world model” companies that build models on top of unique healthcare datasets — things like lab results and CT images.

We’ve also invested in marketplaces that help commercial real estate owners monetize their properties via solar deployments and in autonomous agricultural robots. One thing I enjoy about this job is getting to work on a wide range of problems.

What Moxxie looks for in startups

Two things: founders and market. At the early stage, there’s almost nothing but the founder. We ask if they have a track record of excellence — have they been great at the things they’ve put their mind to? I don’t care whether someone went to MIT or Harvard. That’s one signal of being good in competitive environments, but it’s neither the only nor the best signal.

We care if they’ve done something impressive before and if they’re truly married to the problem: Why this problem, and why now? Are they passionate enough to stick with it for a decade when things get brutally hard — which is the best-case scenario? In the worst case, the startup doesn’t even last a decade.

Second, we look at the market: Does the world actually want what you’re building? You can bang your head against the wall selling something no one cares about for a long time, and it won’t work, no matter how technically strong you are or how successful you’ve been elsewhere. We ask if there’s a clear pull from the market, some timing advantage, unique insight or a distinctive go-to-market angle that suggests the world will pull your product out of you.

A productive first meeting with Moxxie

I can’t fully speak to how to prepare for a “typical” VC pitch, but for us, we want a signal on those two dimensions: founders and market. I like to read materials in advance and don’t enjoy walking through a deck live; I can read on my own time.

In the meeting, we spend a lot of time on questions like: How did you get to this problem? How did you meet your co-founder? Why are you working on this? What do you know about this space that we — or others — don’t? Why are you uniquely suited to do this? Then we dig into market signals: who wants this, what traction or interest exists and what you’re worried about.

If you’re running an early-stage company and claim you’re not worried about anything, that’s usually a red flag — not because there’s nothing to worry about, but because you’re probably missing something. Overall, we aim for an authentic, high-bandwidth conversation rather than a formal, scripted presentation.

Looking for hungry founders

We try to find something non-obvious. Maybe you did something that failed, or your back-channel references are extremely strong, but a couple of people really dislike you, and we want to understand why. Maybe you totally screwed something up before. We care about what you learned and what you’d do differently, not that you’ve never made a mistake.

Personal life stories matter too. People who’ve overcome significant challenges often show a willingness to work incredibly hard and run through walls. We disproportionately invest in immigrant founders; that’s a broad generalization, but often there’s a particular hunger there. We look for that hunger.

What separates successful founders from unsuccessful ones

Ultimately, it’s whether you can build a really good business. Do you understand where the world is going? Can you build something many people will pay for that’s better than other attempts to solve the same problem?

That superiority might come from a unique go-to-market motion, a unique product, being first in a way that’s durable or seeing a problem that no one else sees. There’s some piece of reality you understand that others don’t.

Upside Robotics is a good example. They’re very early, but they build autonomous agricultural robots that can precisely spray chemicals, nutrients or fertilizer in a targeted way instead of the broad spraying that’s common today.

Their core technology works. They’re in the field all day, every day, working alongside farmers. Their customers love them. They’ve shown that farmers using their system can maintain comparable crop yields while spending much less on chemicals, which is good economically and environmentally.

They’ve built something for a very specific group of users — farmers — but that group is a large global market. They’re deeply embedded with those customers, literally programming in the field under a sunshade instead of sitting in an office, wondering why farmers won’t return their calls. It’s early, but it’s a strong example of deep commitment and close customer collaboration.

In the late 1980s, 10-year-old Alex Roetter sat in front of an Apple IIe computer with nothing more than a programming manual and a love for video games. Without formal instruction, he taught himself to code, creating a model rocket simulator and a rudimentary version of Pong — early signs of a builder’s instinct that would shape his career.

That curiosity carried him from Stanford’s undergraduate and graduate computer science programs to early roles at Google, to leading engineering at Twitter, now X, and eventually into venture capital as a general partner at Moxxie Ventures. After more than a decade as an angel investor, Roetter has developed a clear perspective on what makes a startup worth betting on.

The following as-told-to interview has been edited for clarity and concision.