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Position: Senior Full Stack Engineer (Onsite Tech Lead) Location: El Poblado, Medellín, Colombia Schedule: Hybrid (Minimum 3 days/week onsite) Type: Full-Time local employee Experience: 7+ years professional full-stack development; 2+ years leading/mentoring Language: B2 or higher English (written and spoken) Skill Weighting: Backend-heavy, hands-on role ABOUT ARROWFIN We are hiring a Senior Full Stack Engineer to serve as the onsite technical leader for our Medellín engineering team. This is a dual-purpose, hands-on role: you will ship production backend and frontend features across real-time streaming capital market products while mentoring the local team. Our stack is deliberately polyglot. You will manage the complete lifecycle of our applications, including backend, frontend, AI integrations, and future feature builds. We are looking for product owners who seek stability and long-term growth, not project mercenaries. If you thrive on developing state-of-the-art technology in a booming industry, this is for you. WHAT YOU WILL OWN You will not be the only engineer on these platforms, but you are expected to become highly effective across all three within your first few months. Web Trading Platform: B2B/Retail platform replacing legacy desktop apps. Handles order entry, real-time P&L, charting, and auth. Core Stack: Java 25, Spring Boot 4.1, PostgreSQL, Redis, React 19, TypeScript, Protobuf over WebSockets. Performance Analytics: Analytics for individual traders and prop firm evaluations. Core Stack: PHP 8.2 (Laravel 12), NestJS 11, Prisma 7, PostgreSQL, React 19, Socket.IO, Recharts, Playwright. Risk Evaluation: Real-time risk evaluation and automated enforcement on prop firm accounts. Core Stack: NestJS 11, Rust crates, NATS JetStream, Prisma 6, PostgreSQL, React 19, OpenTelemetry, AG Grid. KEY ENGINEERING RESPONSIBILITIES Backend Delivery: Design, build, and operate REST APIs and backend services using Clean/Hexagonal architecture (Java/Spring Boot and NestJS). Data Layer: Own relational models, schema design, indexing, multi-tenant query design, and migrations (Flyway/Prisma) in PostgreSQL. Real-Time Paths: Build event-driven data flows and WebSockets for market data and risk signals that survive and reconcile dropped vendor feeds. Frontend Delivery: Implement complex trading interfaces, high-frequency state, virtualized grids, and correct WebSocket lifecycles in React 19 and TypeScript. Security & Compliance: Build OAuth/OpenID Connect auth flows, handle PII securely, and ensure strict repository secret-scanning hygiene. Observability: Instrument metrics, traces, and structured logs as core feature requirements. Testing: Write unit, integration, and end-to-end tests simultaneously with the feature code. KEY ONSITE TECHNICAL LEADERSHIP RESPONSIBILITIES Raise the Bar: Act as the primary PR reviewer across all three products, focusing on architectural integrity rather than just formatting. Enforce Standards: Maintain testing, architectural, and migration hygiene across repositories with different languages. Mentor: Unblock mid-level engineers in person and cultivate their technical judgment. Technical Design: Translate ambiguous product requirements into clear, actionable technical work detailing affected services and endpoints. Incident Response: Serve as the local escalation point and first responder for staging/production issues during Colombia hours, leading root cause analyses. Global Coordination: Collaborate daily with DevOps, QA, Product Management, and Business Analysis teams globally. Documentation: Write clear architecture decision records and onboarding materials (written clarity is evaluated during hiring). REQUIREMENTS Location: Must reside in the Medellín metro area and work from our El Poblado office at least 3 days a week. Language: B2 or higher English proficiency. Written English is heavily evaluated. Experience: 7+ years building production web applications; 2+ years as a senior/lead engineer. Backend Expertise: Deep proficiency in at least one of Java or TypeScript on the server, with the ability to become productive in the other. (Modern PHP 8.2+/Laravel experience is highly valued). Database Mastery: Hands-on PostgreSQL skills including reading query plans, indexing, safe live-data migrations, and tenant scoping. Frontend Mastery: Strong React/TypeScript experience, specifically building screens that handle high-frequency updates without degrading. Real-Time Systems: Proven experience with WebSocket-based systems, stream interruptions, and data reconciliation. Security: Substantial ownership of authentication systems and an understanding of multi-tenant isolation failure modes. Leadership Track Record: Proven ability to mentor engineers, push back on ambiguous requirements, and professionally disagree with senior stakeholders in written English. NICE TO HAVE Experience in fintech, brokerage, or regulated domains where errors carry financial cost. Familiarity with Rust (even at a reading/small-change level). PHP 8 with Laravel experience. Exposure to real-time market data feeds, order management, or risk systems. Experience with Terraform, GitOps, Prometheus, Grafana, or OpenTelemetry. Previous experience as an onsite senior leader working with remote stakeholders. WHY JOIN ARROWFIN? Massive Impact: You are building a platform that manages millions in transactional volume across three distinct products, not just maintaining a single feature. Real Breadth: Gain exposure to Java, TypeScript, React, Rust-adjacent work, and event-driven services in a highly regulated domain. Code-Forward Leadership: Influence architecture and standards while continuing to ship code. True Stability: You are a core employee, not an outsourced contractor. We are building our own products for the long term. Premium Benefits: Enjoy private insurance, education reimbursement, a supportive local culture, and a stable career path designed for multi-year growth.
Here's how to pick the right one and stand out in your application.
144.883Jobs
31.687IN
81%EN
That number is real. WorkMundi's database shows 144,883 open engineer roles across the world. India has the most with 31,687 jobs, followed by the United States with 30,084. If you just finished reading one job ad and felt paralyzed by choice, you're not alone—but this scale is actually an advantage. It means you can afford to be selective.
Start by geography and language. The majority of engineer ads—117,837 of them—have the job posting text written in English. Use that as one filter, but remember: the ad text language tells you nothing about whether the role actually requires you to speak English day-to-day. Read the job description carefully. Then check which countries have the volume you're targeting. Singapore, Poland, and Australia round out the top five after India and the US.
Next, learn who's hiring. Accenture has posted 2,801 engineer roles. andurilindustries, speechify, and jobgether are also actively recruiting. If you're applying to one of these names, research their hiring patterns and interview style before you apply. That homework pays off.
When you interview, expect the question every engineer hears: 'Tell me about a time you had to debug a problem that wasn't in your job description.' Have a specific story ready—not a general one. Name the tools, the deadline pressure, and what you learned. Hiring managers listen for whether you see problem-solving as part of the role itself, not a favour.