Open to opportunities

Jules Castagnet

@julescastagnet

Message

Full-stack software engineer specializing in high-performance systems and scalable web applications.

France

Message

What I'm looking for

I seek impactful engineering roles building reliable, high-performance systems with collaborative teams, strong testing/CI practices, and opportunities to grow technically and lead projects.

I am a full-stack software engineer with hands-on experience building high-performance trading systems, scalable backend services, and user-focused frontends. I have delivered low-latency C# (.NET) components, event-driven Kafka pipelines, and responsive React/TypeScript interfaces used daily by traders and thousands of end users.

As a founder and lead engineer I built an end-to-end e-commerce platform and automated payment and logistics flows, driving strong month-over-month growth. I prioritize clean code, reliability (99.9% availability), and measurable improvements such as reduced response times, fewer data errors, and improved UX metrics.

Experience

Work history, roles, and key accomplishments

Current

Founder & Lead Engineer

Current

Biweboo Creative

Apr 2023 - Present (2 years 10 months)

Founded and engineered a B2C e-commerce platform for custom art prints handling 500+ monthly visitors, integrated Stripe and automated logistics to cut manual order processing time by 90%.

Stripe React TypeScript SEO Analytics Automation

Front-Office Software Engineer

Crédit Agricole CIB

Mar 2025 - Aug 2025 (5 months)

Designed and built low-latency trading components and full-stack tools for an Interest Rate Derivatives desk, reducing request response times by 30% and ensuring 99.9% availability during trading hours.

C++.NET Kafka React TypeScript CI CD Automated Testing

Academic Project Engineer

Personal Project

Nov 2024 - Feb 2025 (3 months)

Built a modular C# forex backtesting engine to test strategies on 10 years of historical data, optimizing data structures to reduce analysis time by 40%.

C++Optimization Data Structures Financial Engineering Simulation

Software Engineer

Qovoltis

Nov 2023 - Apr 2024 (5 months)

Contributed backend and frontend work for a high-traffic EV charging platform, optimizing PostgreSQL schemas and Python services for 5,000+ active users and improving mobile app rating by 15%.

Python React Next.js TypeScript PostgreSQL Data Integrity Performance Optimization UX

Education

Degrees, certifications, and relevant coursework

EFREI Paris

Master of Engineering, Computer Science

Master of Engineering in Computer Science with a major in IT for Finance & Software Engineering and an international semester at Staffordshire University (UK).