Saena
2026Live
Clinical management platform for psychologists and therapists with Stripe Connect, Google Calendar, and LiveKit video calls.
Next.jsTypeScriptPostgreSQLStripe ConnectLiveKitSentry
Personal project · Solo-builtView project →
Francisco De Haro
Full-Stack for SaaS, payments, and AI.
I work with TypeScript, Next.js, and PostgreSQL to build product software in real environments. I have worked on multi-tenant B2B SaaS, Stripe payment integrations, and production AI automations, covering everything from data models and business logic to delivery and stabilization.
Featured projects
A short selection of product work across payments, AI, and production software.
Fantasktic
2026Live
Production multi-tenant B2B SaaS with PostgreSQL (~150 tables), subdomain authentication, and AI automations.
Next.jsPostgreSQLDrizzle ORMRedisDockerMulti-tenant
Professional · Production SaaSView project →
SAO Psychotherapy
2026Live
Technical audit of a production clinical platform. I traced silent Stripe failures and helped recover over EUR 1,200.
Next.jsPostgreSQLStripe ConnectDrizzle ORMDocker
Freelance · Real billingView project →
Hydra
2026Live
npm package for secure AI tool access with RBAC, AES-256-GCM encryption, and remote execution over WebSockets.
TypeScriptFastifyPostgreSQLWebSocketsCLIAES-256-GCM
Personal · npmView project →
Repai Trainer
2025Live
Published iOS training app with OpenAI, a Supabase backend, and RevenueCat subscriptions.
ExpoReact NativeSupabasePostgreSQLRevenueCatOpenAI API
Own product · App StoreView project →
Testum
2025Live
AI test-exam platform that reached 1,600+ questions and 21,400+ answers through fully organic growth.
Next.jsOpenAISupabasePostgreSQLTypeScript
Personal · Organic growthView project →
CV
Experience, tech stack, and education.
Contact
Summary
Full-stack engineer with experience across company work, freelance engagements, and own products. I worked on Fantasktic, a production multi-tenant B2B SaaS, audited Stripe Connect billing for SAO Psicoterapia, and launched products such as Saena, Hydra, and Repai Trainer.
What I bring
- TypeScript, Next.js, PostgreSQL, and product data modeling
- Multi-tenant B2B SaaS, business logic, and production debugging
- Critical integrations: Stripe Connect, RevenueCat, OAuth, and WebSockets
- OpenAI automations and AI-assisted workflow routing
- Delivery, stabilization, and maintenance of production software
Tech Stack
Frontend & Mobile
Next.jsReactTypeScriptExpoReact NativeXcodeTailwind CSS
Backend & Database
Node.jsTypeScriptSupabaseDrizzle ORMNeonPostgreSQL
Auth & Payments
ClerkStripeRevenueCatApp Store Connect
AI & Machine Learning
LLMsModel APIsFine-tuning
DevOps & Tools
VercelCloudflareCoolifyGitHubCI/CDClaude Code
Education
Business Administration Degree, Universidad de Murcia (in progress)
Languages
Spanish
Native
English
Advanced
French
Basic
About me
I enjoy building products from scratch and seeing real people use them. Testum started as a personal project and ended up with over 21,000 responses purely through word of mouth. That experience confirmed something simple: if a product solves a real problem, people find it. I study Business Administration while building products and working on real projects, which has given me a practical view of how business and technology connect.
Frequently asked questions
Who am I?
I am Francisco De Haro Martínez, a full-stack / product engineer based in Spain. I work with TypeScript, Next.js, PostgreSQL, payment integrations, and AI automations in real products.
What technologies do I work with?
My core stack includes TypeScript, Next.js, React, React Native (Expo), and PostgreSQL. I also have experience integrating language models (LLMs) such as OpenAI, Mistral, and Llama into production products.
How can you contact me?
You can contact me directly via email at frandeharo55@gmail.com.
Availability: Remote · EU timezone. Open to freelance projects, technical collaborations, or positions where I can build product from day one.
Available for collaborations → frandeharo55@gmail.com