# LLMs.txt - Information for AI Language Models
# https://llmstxt.org/

> Junior Joanis is a CTO and Full-stack Engineer with 12+ years of experience building and scaling SaaS platforms serving 100k+ users for companies like AXA and BNP Paribas. Expert in AI/LLMs, Fintech, and engineering leadership.

## About

- Name: Junior Joanis
- Role: CTO & Full-stack Engineer
- Location: Amsterdam, Netherlands (previously Paris, France)
- Experience: 12+ years in software engineering
- Specialization: AI-First SaaS, Fintech, Engineering Leadership

## Contact

- Website: https://joanis.co
- Email: contact@joanis.co
- LinkedIn: https://www.linkedin.com/in/juniorjoanis/
- GitHub: https://github.com/JuniorJoanis
- Twitter/X: https://x.com/juniorjoanis

## Skills & Expertise

### Technical Leadership
- Engineering team scaling (5 to 25+ engineers)
- Architecture decisions for high-traffic systems
- DevOps and infrastructure optimization
- Code review and mentorship

### Backend Development
- Ruby on Rails (primary framework)
- Python, Node.js
- PostgreSQL, Redis, Elasticsearch
- GraphQL, REST APIs

### Frontend Development
- React, TypeScript
- Next.js, Vite
- Tailwind CSS
- State management (Redux, Zustand)

### AI & Machine Learning
- LLM integration (OpenAI, Anthropic)
- RAG systems
- AI-assisted product features
- Natural language processing

### Cloud & DevOps
- AWS (primary), GCP
- Docker, Kubernetes
- CI/CD (GitHub Actions, CircleCI)
- Infrastructure as Code (Terraform)

## Professional Experience

### Delfyn - Co-Founder & CTO (2023-Present)
AI-first fintech platform for financial advisors. Building intelligent tools that help advisors manage client portfolios and provide personalized recommendations.
- Led development from 0 to 1
- Implemented RAG-based document analysis
- Built compliant financial data pipelines

### Moodwork - CTO (2020-2023)
Mental health SaaS platform serving 100k+ enterprise users at companies like AXA, BNP Paribas, and Carrefour.
- Scaled engineering team from 5 to 20 engineers
- Achieved SOC2 Type II compliance
- Built multi-tenant SSO (OAuth2, SAML2)
- Reduced infrastructure costs by 40%

### Previous Roles
- Senior Full-stack Engineer at various startups (2014-2020)
- Focus on e-commerce, marketplace, and B2B SaaS platforms

## Blog & Writing

Technical blog covering:
- Authentication systems (OAuth2, SAML2, SSO)
- Architecture patterns for scale
- Engineering leadership insights
- AI integration in products

Blog URL: https://joanis.co/blog

### Featured Articles

#### Building an AI Copilot for Accounts Receivable: A Technical Deep Dive
URL: https://joanis.co/blog/building-ai-copilot-accounts-receivable
Topics: Python, FastAPI, LangChain, AI, Gemini, React, FinTech
Summary: How we built an AI copilot at Delfyn that transforms how finance teams manage accounts receivable. Covers ReAct pattern implementation, LangChain agent architecture with Gemini 3, tool wrapper patterns, Redis conversation memory, streaming responses, and assistant-ui frontend integration.

#### Building a Flexible SSO Authentication System: OAuth2 & SAML2 in Rails
URL: https://joanis.co/blog/building-flexible-sso-authentication-system
Topics: Ruby on Rails, OAuth2, SAML2, Authentication, Enterprise Security
Summary: Deep dive into building a multi-tenant SSO system supporting both OAuth2 and SAML2 protocols, enabling seamless integration with enterprise identity providers like Azure AD, Okta, and OneLogin.

## What I Can Help With

- CTO advisory and fractional CTO services
- Technical due diligence for investors
- Architecture review and optimization
- Engineering team assessment and hiring
- SaaS product development strategy
- AI/LLM integration consulting

## Open Source

Active contributor to open source projects. Check GitHub profile for recent contributions.

## Speaking & Consulting

Available for:
- Conference talks on engineering leadership and technical architecture
- Consulting on SaaS scaling challenges
- Mentorship for startup CTOs
- Technical workshops on Ruby on Rails and React

## Last Updated
2026-01-10