Full Stack Engineer

Full Stack Engineer

ArrowFin Colombia SAS | Medellin, Antioquia, Colombia (Hybrid)

📍 El Poblado, Medellin, Colombia

🗓 Hybrid - minimum 3 days onsite

💼 Full-Time Local Employee

📅 5+ years of professional full-stack development

About ArrowFin

Join ArrowFin Colombia SAS to lead development of our active trading platform and performance analytics applications. We are a vertically integrated CME futures exchange building B2B risk products for prop firms and retail traders.

We build products for our own company and grow our team internally. You will be joining a dedicated team of engineers in our office in El Poblado, working closely with product managers, QA, and business analysts to ship high-quality software at scale. We expect this platform to serve 10,000 or more customers. We are looking for builders who want ownership and long-term growth, not temporary contributors.

What You Will Build

Our platform serves active traders using the our web platform to directly access and trade the futures and commodities markets.

Multi-tenant data isolation is central to the architecture. Cross-tenant access is a P0 bug. Trader PII including account balances and transaction data is regulated under CFTC/NFA rules. You will be expected to enforce these boundaries at the code level.

Key Responsibilities

▸ Full Stack Ownership - Own full stack feature delivery across trading interfaces and backend services, from data layer to UI

▸ Frontend Development - Design and implement complex, real-time trading interfaces using Next.js 15 (App Router), React, and TypeScript

▸ Backend Development - Build and maintain backend services and REST APIs using Node.js and NestJS. Clean, hexagonal architecture is the preferred pattern

▸ Data Layer - Design and maintain relational data models and queries in PostgreSQL using Prisma ORM, with a focus on performance, indexing, and multi-tenant isolation

▸ Real-Time Data - Implement and maintain WebSocket connections for real-time market data and event-driven features, with tenant scoping enforced at auth time

▸ Security and Compliance - Build auth and session management systems appropriate for a CFTC/NFA regulated environment. PII handling and threat modeling are part of the role

▸ Communication - Translate business requirements into clear technical tasks and produce documentation other engineers can build on. Written clarity is evaluated

▸ Build Practices - Contribute to documentation, onboarding materials, and code review culture

Requirements

🔴 Hard Requirements

▸ B2 or higher English proficiency. Written English is evaluated in the technical assessment

▸ 5+ years of professional experience building web applications in production

▸ Must be based in Medellin or the Medellin metro area

🔵 Technical Requirements

▸ Frontend - Strong expertise with React and TypeScript. Next.js 15 (App Router) experience required or must be acquired quickly

▸ Backend - Solid experience with Node.js and NestJS, including REST API design. Express background is a fine foundation; NestJS proficiency is expected

▸ Database - Hands-on PostgreSQL including schema design and query optimization. Prisma ORM strongly preferred

▸ Real-Time - Solid WebSocket implementation experience, including tenant-scoped connections

▸ Auth and Security - JWT, session management, and multi-tenant isolation patterns

▸ Testing - Meaningful unit tests required. Jest experience expected

🔵 Deep Understanding Of

▸ Component-based architecture and frontend state management (Redux, Zustand, or similar)

▸ Hexagonal or clean architecture patterns on the backend

▸ REST API integration and event-driven backend patterns

▸ Performance optimization including virtualized lists, memoization, and granular subscriptions

▸ Database indexing strategies and multi-tenant query design

Nice-to-Haves

▸ Fintech, trading, brokerage, or regulated domain experience

▸ Docker and AWS familiarity

▸ Real-time market data feeds and event-driven architecture experience

▸ Redis for session caching or pub/sub

▸ React Testing Library, Cypress, or Playwright

About the Technical Assessment

Candidates who advance past the initial screen receive a 2-3 hour take-home assessment built on the NestJS, Next.js, Prisma, and PostgreSQL stack above. Partial submissions are accepted. AI tool use is permitted with disclosure.

Assessment scoring:

▸ Security and PII Judgment - 30%

▸ Backend Correctness - 20%

▸ Frontend Quality - 20%

▸ Communication and Documentation - 20%

▸ Architectural Reasoning - 10%

Why Join ArrowFin?

▸ Impact - You are building a platform that manages millions in transactional volume. Your work directly affects the experience and profitability of our trading customers

▸ Career Growth - This role is designed to evolve with the product and the organization over a multi-year roadmap

▸ Stability - You are not a contractor hired out to others. You will work in a local team that supports our products directly

▸ Benefits - Private insurance, education reimbursement, strong team culture, and a stable career path