Fullstack Staff Engineer

About DEUNA 🧡 DEUNA is a rapidly growing startup revolutionizing global commerce with ATHIA, our AI-powered orchestration and payments platform that helps large enterprises boost approval rates, reduce costs, and unlock new revenue. Built by the team behind DEUNA—the fastest-growing Commerce OS in Latin America—ATHIA combines payment intelligence, checkout optimization, and data orchestration in one powerful solution. With deep integrations across 300+ PSPs and alternative payment methods, and over 20% of Mexico’s digital economy running through our platform, we simplify global payments through a single integration and centralized reconciliation. We are a rapidly growing startup expanding into the U.S. to meet the urgent needs of large retailers, marketplaces, airlines, and QSRs. Join us to shape the future of payments! 🚀 Visit https://www.deuna.com/ to learn more about us! Role Overview

We are looking for a Staff Software Engineer – Fullstack to act as a senior technical leader across our engineering organization.

This is a high-impact individual contributor role , focused on driving architecture, setting technical direction, and solving complex, cross-team challenges. You will partner closely with Engineering, Product, and leadership to ensure our systems scale reliably as the business grows.

This role is not focused on people management — instead, you will operate as a technical authority and multiplier , influencing multiple teams and raising the overall engineering bar.

What You’ll Do

• Technical Leadership & Architecture

• Own and evolve the architecture of critical fullstack systems across frontend and backend.

• Lead the design of scalable, high-performance, and resilient distributed systems.

• Set and uphold engineering standards, best practices, and design principles.

• Drive alignment across teams on architectural decisions and technical direction.

• Hands-On Engineering

• Contribute to high-impact areas of the codebase.

• Write clean, maintainable, production-grade code.

• Lead complex refactors and performance optimization efforts.

• Conduct in-depth code reviews and mentor engineers through technical guidance.

• Cross-Team Impact

• Partner with Product and Engineering leaders to evaluate trade-offs across scalability, performance, cost, and security.

• Design APIs, data models, and system interactions that support long-term growth.

• Guide teams on handling edge cases, failure scenarios, and observability.

• Technical Strategy & Innovation

• Identify system bottlenecks and drive scalable solutions.

• Influence long-term technical strategy and roadmap.

• Evaluate and introduce new technologies where they add meaningful value.

• Improve monitoring, instrumentation, and system reliability practices.

What We’re Looking For

• Proven experience as a Staff, Principal, or Senior Software Engineer in fullstack environments.

• Strong frontend expertise with:

• React

• Next.js

• TypeScript

• Strong backend experience with:

• Golang and/or Python

• Deep experience designing distributed systems and scalable APIs .

• Strong fundamentals in:

• Data structures and algorithms

• System design and architecture

• Design patterns and trade-offs

• Hands-on experience with AWS and cloud-native architectures .

• Experience with SQL and NoSQL databases .

• Strong debugging, performance optimization, and refactoring skills.

• Excellent communication skills, with the ability to influence technical decisions.

• Fluent or native English (Spanish is a plus).

• Nice to Have

• Experience in payments, fintech, e-commerce, or transaction-heavy platforms .

• Experience building high-availability, low-latency systems .

• Familiarity with regulated environments (PCI-DSS, financial systems, etc.).