Francisco De Haro

Applied AI and LLM Evaluation Specialist.

I integrate LLMs into real-world use cases (education, economics, product), turn ideas into demos in days, and publish comparable results (cost/latency/accuracy). I aim to raise awareness of AI and anticipate its effects with evidence and practical judgment. I work as an independent end-to-end developer; short cycles, continuous delivery, and a focus on outcomes. 430+ GitHub contributions in the last 12 months (mostly private).

Next.jsReactExpoTypeScriptSupabasePostgreSQLAPIs IARevenueCat

Featured projects

A collection of projects I've worked on, from web applications to AI integrations.

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Repai Trainer logo

Repai Trainer

Live

Repai Trainer is a personalized AI-powered training mobile application, available on the App Store. Fully developed by me from scratch, it combines a native iOS frontend with Expo/React Native, a robust Supabase backend, subscription system with RevenueCat, and workout generation using GPT-5. The app allows users to create personalized routines, track their progress, and receive intelligent exercise recommendations based on their goals and performance.

ExpoReact NativeSupabasePostgreSQLRevenueCatApp StoreAPIs IAGPT-5

Personal project currently on development pause.

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UMChat - Sistema de Chat Avanzado logo

UMChat - Advanced Chat System

Live

UMChat is an intelligent chat web application built from scratch with a complete system for managing conversations, documents and authentication. The project demonstrates expertise in modern full-stack development, complex data architecture and performance optimization. Includes AI integration, automatic OCR, intelligent file deduplication, real-time streaming, and an architecture of 8 tables with complex relationships. Built with Next.js 14.2, React 18.3, TypeScript, PostgreSQL with Supabase, and multiple external APIs.

Next.jsReactTypeScriptxAIGrokSupabasePostgreSQLMathpixServer-Sent EventsRow Level Security

Personal project representing the evolution of Testum towards a complete conversational platform.

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Testum logo

Testum

Live

Testum is a web platform developed with Next.js that allows creating and taking multiple-choice exams quickly and effectively. Users can upload their own exams and solve them with a highly polished UX experience. The project reached +1600 questions to solve and +21400 accumulated answers, spread solely by word of mouth among students of the Business Administration degree at my university. It includes an integrated AI chat with OpenAI to help users while answering, authentication with Supabase, and PostgreSQL database to store all information.

Next.jsOpenAISupabasePostgreSQLEdge FunctionsTypeScriptUX

Personal project developed for Business Administration students at my university.

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Demo Mistral Chat logo

Demo Mistral Chat

Live

A modern chat web application that demonstrates Mistral AI capabilities. Built with Next.js 14 and deployed on Vercel Edge, it implements real-time response streaming for a fluid and responsive user experience. The project explores best practices for integrating LLMs into web applications, including context handling, prompt optimization, and efficient conversation state management.

Next.jsMistral AITypeScriptEdge FunctionsStreaming
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Fine-tuning Llama para Letras en Español logo

Llama Fine-tuning for Spanish Lyrics

Archived

Fine-tuning project of Llama models (3.3 1B/3B and 3.1 8B) to produce coherent Spanish song lyrics with consistent structure, rhyme, and theme. Optimized to balance quality and cost through advanced techniques like QLoRA 4-bit and Unsloth. The project includes a complete custom scraping pipeline developed with Playwright to create a robust dataset of +10,000 prompt-completion examples, intelligent tokenization system with masking, and efficient training architecture with A100 achieving high-quality results with ~24.3M trainable parameters.

PyTorchLlamaFine-tuningQLoRAHugging FaceUnslothNLPTransformersbitsandbytesPEFT

Personal experimentation project with LLM fine-tuning. Training performed with A100 GPU.

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LoRA Black Stories - Generación de Imágenes logo

LoRA Black Stories - Image Generation

Archived

LoRA adapter training project to replicate the characteristic visual aesthetic of "Black Stories" and generate new stories/scenes with visual consistency. The project includes meticulous dataset curation, autocaptioning system to strengthen style, trigger word definition for precise style control through prompts, and multi-resolution training (512-1024) to improve generalization. It includes a rigorous aesthetic QA process reviewing composition, silhouettes, contrast, contours, and coherence between samples to ensure stable and reproducible aesthetics. Trained on Black Forest Labs FLUX models (flux-schnell and flux-dev).

FLUXLoRAComfyUIImage GenerationFine-tuningComputer VisionDiffusion ModelsBlack Forest Labs

Personal project for own use in image generation and style control experimentation.

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1¢, 1min, 100%: AI en Exámenes Universitarios (En desarrollo) logo

1¢, 1min, 100%: AI in University Exams (In Development)

Dev

Opensource research paper on the application of artificial intelligence models to Business Administration and Management exams at the University of Murcia, Spain. Results and methodology are publicly available. Results demonstrate that advanced reasoning models like GPT-5-mini (high reasoning) and grok-4-fast-reasoning achieve 100% accuracy in less than 1 minute per exam, with an approximate cost of 1 cent per evaluation. This study includes the development of an OCR system implemented with Mathpix API and LATEX/Markdown conversion program to automate exam processing. SQLite database with Prisma for efficient data management.

ResearchAIPythonOCRMathpixLATEXSQLitePrismaUniversidad de MurciaOpensource

Academic research in development. Results are preliminary and subject to review.

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Personal Portfolio

Live

This website. Personal portfolio built with Next.js 14 App Router, TypeScript, and Tailwind CSS. Minimalist dark mode design.

Next.jsTailwind CSSTypeScriptReact

CV

Experience, tech stack, and education.

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Contact

Email

frandeharo55@gmail.com

Location

Spain

Portfolio

deharo.dev

Summary

Full-stack developer focused on Next.js/TypeScript and Python, shipping user-centric products end-to-end (web + mobile with Expo) with solid backends (Supabase/PostgreSQL/Node). Strong with APIs—designing and integrating REST/GraphQL/streaming endpoints and third-party SDKs (auth, payments, observability). Practical AI integrations (Mistral, OpenAI, Llama): prompt orchestration, evals, and lightweight RAG; shipped products with subscriptions and CI/CD. Immediate availability; open to relocation and a sabbatical year for the right project.

What I bring

  • Frontend (Next.js/React) and mobile (Expo) design and development
  • APIs and backend in Node/TypeScript (Supabase, PostgreSQL, Neon)
  • Authentication and payments (Clerk, Stripe, RevenueCat, subscriptions)
  • LLM integration (Mistral, OpenAI, etc.), prompt orchestration and deployments
  • Practical DevOps: Vercel, Cloudflare, GitHub, CI/CD

Tech Stack

Frontend & Mobile

Next.jsReactTypeScriptExpoReact NativeXcodeTailwind CSS

Backend & Database

Node.jsTypeScriptSupabaseNeonPostgreSQL

Auth & Payments

ClerkStripeRevenueCatApp Store Connect

AI & Machine Learning

LLMsMistral AIOpenAIPromptingAPI Integration

DevOps & Tools

VercelCloudflareGitHubCI/CDCursor

Education

Business Administration and Management Degree (BBA)

Currently 3rd year

Fast learning and technical autonomy

Languages

Spanish

Native

English

Advanced

French

Basic

About me

I'm Francisco and I like building useful things fast with a love for UX. I enjoy 0→1, measuring before opining, and shipping in short cycles. When I'm not coding, I experiment with LLMs, evals, and small automations that save me time. I prefer clear code, CI that doesn't get in the way, and products people want to use. I'm motivated by turning ideas into products in days, not months. If there's data, we do science; if not, I prototype and measure. Low ego, high delivery. I believe the world needs to know about AI, as in my environment and university classes I'm one of the few who understands its importance and especially sees the trajectory and where AI is heading with its future capabilities.

Availability: Immediate start available on-site EU (4–6 months internship). Open to full-time conversion after internship.

Available immediately for collaborations → frandeharo55@gmail.com