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.).