Meet the Team
Marco Esquivel
AI Consultant & Systems Builder
Founder of Build Lean. Five years of enterprise backend at American Express, plus a year-plus of AI-native operating, combined into one end-to-end technical partnership.
Five years at American Express
Distributed systems backend engineering inside the Digital Acquisitions org.
I started at American Express in August 2021 as a backend engineer in the Digital Acquisitions organization, the team that powers the pre-submission side of Amex credit card acquisitions.
I built and maintained services that integrated with major B2B partners like Delta, Hilton, Marriott, and Credit Karma, wiring up custom flows that let each partner present Amex offers inside their own surface. On the other side of the stack, I worked closely with marketing technologies and content orchestration systems to deliver targeted card offers to consumers and businesses based on their context.
Working in financial services, on revenue-generating systems, the bar wasn't optional. High availability, scale, and security weren't features we added, they were day-one expectations. Five years of that builds a particular muscle: shipping software you can trust at the seams it touches.
Operator era: building, marketing, learning
Nights and weekends turned into a self-built bootcamp on running a business end to end.
In early 2025 I started experimenting with startup-style projects on the side, building everything by hand, no AI, no shortcuts, and frankly no real understanding of how to run a business end to end. With a full-time job, time was the bottleneck and progress was slow.
Then AI started compounding. I went from copy-pasting ChatGPT outputs to running Claude Code with Opus, to standing up real infrastructure in AWS and GCP with Terraform. Building stopped being the bottleneck almost overnight.
So I turned to everything else. Custom CRMs to track my own engagement on Meta ads with auto-follow-up webhooks. Agentic, fully autonomous email-marketing newsletters. Agentic prospecting and cold outreach pipelines for sales. Short-form content with HeyGen and ElevenLabs. Connector-driven first-draft marketing inside Canva. And dozens of small custom tools in between to manage quality, output, and the time and money budget I was bootstrapping under.
There was no course. It was trial and error, constantly tweaking, constantly experimenting, building tools when the off-the-shelf ones didn't fit. Nights and weekends turned into a self-built bootcamp on what an AI-native operator actually does.
Why Build Lean
I realized the moat that made SaaS valuable just disappeared.
Bootstrapping a D2C business takes time and capital I didn't have. But somewhere in the grind, the bigger pattern hit me: the large upfront effort that used to make SaaS valuable, and gave it its barrier to entry, was suddenly gone.
Every business can now unlock real operational outcomes with the right focus, the right guidance, and custom tooling, without subscribing to the next 50 AI SaaS tools and bolt-on features. Tooling built specifically for your workflows is becoming cheaper to deliver and easier to adopt than stitching together a SaaS landscape where every team gets 5 to 10 separate apps.
After a few engagement pilots, the outcomes were obvious. The competitive advantage of custom strategy plus custom implementation, delivered AI-natively, is real.
A year-plus of bootstrapping, building, and operating in an AI-native way, paired with five years of enterprise software in a regulated, revenue-generating environment, is a different shape than a McKinsey-style consultant or a generic AI engineer. Build Lean is where I bring that combination to bear: a business-focused, white-glove, end-to-end technical partnership.
Want to build something together?
Tell me what you're trying to solve. I'll tell you straight whether custom is the right call, and if it is, what it would take.