Fractional CTO · Greater Toronto Area, Ontario, Canada

About Mario Meyer

A fractional CTO sells judgment, not code. And judgment is mostly experience you have already paid for. Here is where mine came from.

Mario Meyer, Fractional CTO

I grew up in Rio, fell for Canada on a university exchange, and have spent twenty-five years building technology on two continents — enterprise systems, a factory, an oil-and-gas operation, national networks, then startups. Today I am a fractional CTO and the founder of Reyem Tech, and the job is mostly judgment: helping founders and owners make the hard technology calls, then handing the decision back. Getting here was not a straight line.

Helping a founder or owner make those calls well is what Reyem Tech is for. The rest of this page is how the judgment got built.

Roots

I grew up in Rio de Janeiro, in a family of military officers and academics. My mother bought a computer for her PhD when almost no home in Brazil had one, and I taught myself by poking at it. I was eight. By my teens I was doing real tech work at my uncle's company, which built systems for the Brazilian Navy. At sixteen I was teaching master's students how to build and maintain hardware. None of it was a plan. It was just where the curiosity led.

That household left me a few rules I still run on: do it properly, stay honest about what is true, earn your place by what you deliver. My favourite example is a small one. Three months before I was of legal drinking age, my admiral uncle refused to pour me a beer — then promised me all the beer in the world the day I came of age. Discipline and warmth from the same man.

The real turn came on an exchange term at the University of Alberta, in Edmonton. It changed my life. I fell for how things worked in Canada — most of all the idea that what you do matters more than who you know. That idea did not leave me.

Getting the baggage first

Back in Brazil, I set out to get the baggage first. Through university I built ERP systems for large manufacturers, the youngest developer on the team. At twenty-two I led Brazil's Ubuntu Linux community.

At twenty-five I was handed a management role at a global manufacturer and helped build a factory — not just its software, but its production lines and the few hundred people putting it up.

After that I ran the data, architecture, and systems for a major oil-and-gas construction company, several dozen sites at once, from refineries to deep-sea drilling modules to pipelines. Then I ran the points of presence for Brazil's academic internet network, leading distributed teams full of PhDs twenty years my senior. I learned more about leading people in those rooms than any classroom could teach.

The leap, and the hard years

Leaving Brazil was not a casual move. I gave up a tenured job — the kind most people there work a lifetime for, the kind you cannot be fired from. I walked away anyway. Something made me reassess what safety, and a life, are really worth. Once I had, I planned the move for years and opened a company before I landed.

I arrived with a business ready to run. Two months later, the pandemic hit. That first venture was the Canadian arm of a Brazilian tech company, and its whole model ran on foot traffic, in one of the most locked-down cities in the Americas. The timing was as bad as timing gets.

So I drained my savings and cold-called an empty city. I did not quit. Eventually a fractional-CTO contract came through, and I built from there: contractor, then associate partner, several clients at once. Around then I became a father. It did not change what I did so much as how far ahead I was suddenly willing to think. Four months later a downturn took the role, about two weeks before a trip home I had planned for a long time.

Sometimes it's better to lose a great deal than risk making a terrible one.

Mario Meyer

Building it twice

Here is what I got half wrong, then right. I came to Canada chasing the meritocracy: what you do over who you know. Then I learned that business here runs on trust — referrals, a name vouched for, the relationship before the transaction. So I took that on too, deliberately, as a second profession. I came for the merit and stayed for the relationships, and it turned out I needed both.

Somewhere in there I saw something obvious in hindsight: I had been doing the sales, the pipeline, and the partner work to build someone else's firm, and I could build my own. So I did, at night, during a vacation back in Brazil — the days for family, the nights for building — then came back to Canada with the company already running. The first time I had arrived that way out of necessity. This time it was a plan.

The groundwork was already there. Years of relentless networking had quietly built a name here while I was not looking — several events a week, and a chamber-of-commerce board where I lost the first race by two votes, came back the next year to win, and now serve as vice president. So the second time, the contracts came in weeks, not the lean year that rebuilding my life had cost me.

What I do now

The lesson under all of it is the one I give every founder and owner I work with: technology only matters when it is tied to the business. That is the work now. I bring what those years built into the room, and I aim to leave a team deciding better on its own than when I arrived.

It is judgment you are hiring, not a résumé. When a call is too important to get wrong, that is the conversation I like — and it runs through Reyem Tech.

Credentials & affiliations

Today I am the founder and CEO of Reyem Tech, a boutique technology advisory firm, and I work as a fractional CTO. Over the years I have led technology across software, professional services, and healthcare, and shipped production systems on most of the stacks a founder or owner is likely to be on — which mostly taught me that the stack is the easy part; the harder, more valuable call is which one actually fits the business in front of you. That range includes regulated healthcare data: at Inagene Diagnostics I led the technology handling protected health information across both the lab and the client platforms, under CLIA and UKCA certification. Long before the advisory work I ran the systems myself: three years as the applications and systems manager for a large oil-and-gas construction company, owning the ERP, the project-management software, the ticketing system, and the service-oriented architecture; and seven years accountable for every point of presence on Brazil's national research-and-education backbone — over two hundred people across more than two dozen teams, nationwide. I have also built and hired the engineering teams behind early-stage startups — Mazlite, Inagene, and Welbi among them — work reflected on my Crunchbase and Wellfound profiles.

My education runs through PUC-Rio and the University of Alberta, and an MBA at Fundação Getulio Vargas that included an executive-education module in entrepreneurship at Babson College.

Affiliations

I believe in giving back, plainly. People helped me at every stage of my career, and I have come to think the more you help others, the more finds its way back to you. That is most of why I give these communities my time — and why I try to leave them a little stronger than I found them.

Fractional CTO · AI strategy · technical due diligence · team building

What I build with

This is what I reach for when there is software to build. For a lot of businesses the harder, higher-value work is the operations, data, and process around it.

What I run now

AI & ML
LLMs · RAG · agent workflows · MCP servers (FastMCP) · vector search · eval-first delivery
Architecture
microservices · event-driven · serverless · REST & GraphQL API design
Languages & frameworks
TypeScript · Python · PHP · Ruby · Rails · Laravel · Django · FastAPI · React · React Native · Next.js
Data
PostgreSQL · Redis · ClickHouse · Neo4j · MySQL/MariaDB · data lakes & analytics
Cloud & DevOps
AWS & Azure (multi-cloud) · Kubernetes · Pulumi · Terraform · Docker · Helm · GitOps (ArgoCD) · CI/CD · Prometheus/Grafana
Security & compliance
PHI/PII handling · data residency (Canada + UK) · PII redaction & data minimization · RBAC / least-privilege access · audit logging · revocable consent-based sharing
Business systems
Odoo (ERP) · HubSpot · Bitrix24 · Nutshell · SugarCRM

What I've shipped over twenty-five years

Enterprise & industrial
ERP for large manufacturers (JD Edwards, TOTVS) · production-line & shop-floor systems · oil & gas data & architecture
Networks & infrastructure
national research & education networks · points of presence & data centres · Linux/Unix at scale · open-source community leadership

Questions people ask before we talk

How does this site relate to Reyem Tech?

Reyem Tech is the firm I founded; this site is just me. The writing, the story, and the judgment here are first-person — mine. When there is actual work to do, it runs through Reyem Tech, where the team and the process live. Think of this page as the person, and Reyem as the practice.

What do you actually do as a fractional CTO?

I help founders and owners make the technology calls that are too important to get wrong — architecture, AI adoption, build-versus-buy, hiring — and then I hand the decision back, so the team is deciding better on its own than when I arrived. It is judgment you are hiring, not a résumé. The aim is to leave having made myself unnecessary.

Where does your experience come from?

Twenty-five years building technology on two continents — enterprise systems and a factory floor in Brazil, an oil-and-gas operation, national research networks, then years of startups and owner-led businesses in Canada. The through-line is not a single industry; it is having seen enough of them to know the right answer is rarely the same answer twice.

Do you work alone, or is there a team behind you?

Both, depending on what the work needs. Some engagements are just me, in an advisory seat. When the work calls for real delivery — engineers, security, the build itself — that runs through Reyem Tech, so it is not resting on a single pair of hands. Either way I stay close enough to be accountable for the outcome.

What kinds of businesses do you usually work with?

Mostly founders and owner-led companies — the ones where one or two technology decisions carry real weight and there is no senior technical voice in the room to weigh them. I have worked across software, manufacturing, healthcare with regulated data, and professional services. What they share is not a sector; it is a moment where the technology has to be tied to the business, not chosen for its own sake.

How would we start working together?

Through Reyem Tech. The lowest-friction way in is a Technology Health Check — a look at where things actually stand before anyone commits to more. If it is a fit, we take it from there; if it is not, you will still leave knowing more than you came with. I keep that part off this page on purpose: this is where you decide whether you trust me, not where you buy anything.