Systems Product Builder

I turn complex product ideas into production-ready systems using AI-assisted engineering.

As a Product Engineer with founder experience, I specialize in mobile architectures (iOS/Swift), local-remote data sync, HealthKit, and conversational AI agents. I design clean logic, iterate rapidly, and focus on metrics.

Explore Projects Get In Touch
Raúl Medina Reigada

115K€

Seed Capital Managed

5K+

App Downloads

10 Days

MVP to Production

C1

English Fluency

Featured Case Studies

Real engineering challenges solved systematically.

Drop It

AI-Agent & Biometrics iOS App

Active Product
Drop It App Mockup

A menstrual cycle and workout synchronization system that dynamically adapts training plans based on daily physiological biofeedback and symptoms.

Menstrual & Biofeedback Engine

Designed mathematical models calculating cycle phases and fatigue limits to optimize training volume.

Adaptive Workout Logic

Architected the core system managing exercise categories, rep schemes, and dynamic training session adjustments.

Conversational AI Agent

Built a real-time streaming assistant to evaluate user context and dynamically mutate workout templates.

Swift / SwiftUI Algorithm Design Supabase / Postgres Agentic AI

Fiber

Algorithmic Load Recommendation App

Completed Project
Fiber App Mockup

An algorithmic load prediction training app built from scratch in 2 months to recover a failing project and restore investor confidence.

Rapid Recovery

Replaced a failed external agency, self-teaching mobile system architecture and shipping a fully functional app in 8 weeks.

Personalization Algorithm

Implemented a mathematical engine recalculating Estimated RM and recommending weights based on RM/RIR.

Cap Capital Management

Co-founded the startup and managed €115,000 in seed capital, directing initial operations and roadmaps.

iOS / Swift CoreData Algorithmic Design Seed Stage Ops

Architectural Lab

Exploring modern cross-platform ecosystems, hybrid mobile containers, and growth engines.

One Lift

Kotlin Multiplatform

Cross-platform mobile exploration sharing core workout algorithms and local data models natively between iOS and Android codebases using Kotlin Multiplatform (KMP).

Pentagogym

Next.js + Capacitor

Hybrid mobile prototyping, mapping a Next.js web application styling with Tailwind CSS and Supabase integrations inside a native iOS container.

Growth & GEO Engine

SEO / LLM Optimization

Advanced search and AI search engine optimization (GEO) utilizing dynamic MDX, i18n routing, and schema structures to optimize indexing for agents like ChatGPT Search and Perplexity.

My Philosophy

How I Build

01

Outside-In Design

I start with the target behavior and business metrics. The backend logic, schemas, and APIs are built strictly to serve these outcomes, eliminating waste.

02

Defensive Engineering

Before starting, I isolate complex systems, trace dependencies, and map edge cases in advance to prevent structural bugs down the road.

03

Supervised AI Workflows

I use AI as a high-speed execution layer. I orchestrate 100% of the software architecture, database designs, and review every generated block for quality.

04

Data-Driven Debugging

When tracking bugs, I avoid random code trials. I design clear, structured system logs to isolate failures in asynchronous states and state machines.

Let's Connect

Looking for an autonomous builder to turn complex ideas into production-ready software?

I am actively open to roles as a Product Engineer or Product Builder in fast-paced startup teams. I specialize in bridging the gap between product strategy and high-speed execution through AI-assisted engineering, based in Tarragona, Spain (Open to Remote / Hybrid).

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