Alejandro Castro — Software Architect & Fractional CTO.

I am a software architect and fractional CTO with 36 years shipping production software. I have owned payment software integrating 100+ gateways for systems that handled hundreds of millions of USD in incoming transactions, plus accounting, finance, and operations platforms. I built and led an accounting and financial systems department, and I still write critical-path code.

Most engagements separate thinking from building. A consultant tells you what to build. A freelancer builds what you tell them. An agency hands off between account managers, project managers, and developers. Each handoff loses information.

I don't do handoffs. I do end-to-end delivery. I lead every engagement from strategy through deployment. When a project needs a specialist — a designer, a data engineer — I bring them in. But you never manage them. I manage them. One point of accountability, one result.

My portfolio includes AIDA — an enterprise tax compliance platform reconciling over a million rows across SAP and Procore (7-month solo build, 1,128 passing tests), an AI persona clone with voice interaction and RAG over private documents, a 14-service SaaS admin platform behind a Kong gateway, and a privacy-first teleprompter PWA where your microphone never leaves the browser.

I work with finance, payments, and operations leaders whose money-movement, reporting, or core workflows outgrew off-the-shelf software — and still run on spreadsheets, desktop tools, and manual batch processes — and with founders who need a platform designed and built by one accountable person. Most engagements start with a bounded architecture diagnostic: one to three weeks, fixed price, ending in a decision rather than a proposal. I advise on build vs rent: own the systems that differentiate your business, rent the commodity layers. One engagement, one point of accountability, your platform shipped.