Onsite Technical Lead (Fullstack) – Fintech🚀

At ArrowFin, we support the construction and optimization of high-performance technology solutions that power our clients' trading activities directly on the Chicago Mercantile Exchange (CME). We develop our own software—no outsourcing or third-party client work—backed by an engineering team focused on real-time systems and distributed architecture.

Role

We are hiring an Onsite Senior Full Stack Engineer (Technical Lead) for our office in El Poblado, Medellin. The role has a dual purpose: ship production code for our real-time streaming trading products, and serve as the onsite technical anchor and mentor for our local engineering team.

Key Responsibilities

• Full Stack Development: Design and build resilient backend microservices and REST APIs, alongside complex, high-performance frontend interfaces.
• Leadership & Mentorship: Lead code reviews, mentor local mid-level engineers, and translate product requirements into clear, unambiguous technical specifications.
• Real-Time Systems & Security: Maintain WebSocket data flows, optimize PostgreSQL queries, and ensure strict multi-tenant data isolation and security standards.
• Local Escalation: Act as the primary technical responder during Colombia business hours for staging and production incidents.

Required Stack & Qualifications

Hard Requirements

• Location & Language: B2 or higher English proficiency and based in surrounding areas of Medellín or open to relocate (onside role).
• Experience: 7+ years in professional full stack web development, including at least 2 years in a Senior or Tech Lead role.
• Backend: Deep expertise in Node.js / TypeScript (NestJS) and clean/hexagonal architecture. Willingness to work in a polyglot backend environment.
• Frontend: Strong mastery of React + TypeScript, state management, and high-frequency UI updating components.
• Database & Real-Time: Solid PostgreSQL experience (query optimization, indexing, and migrations) alongside WebSockets or event-driven patterns.

Nice to Have

• Background in Fintech, trading, brokerage, or other low-latency regulated environments.
• Familiarity or interest in Rust.
• Exposure to DevOps and Observability tooling (Docker, Prometheus, Grafana).