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!

We are looking for a Fullstack Staff Engineer to serve as a senior technical authority across our engineering organization. This role is designed for a highly experienced engineer who operates at a strategic level, shaping architecture, driving technical standards, and solving complex cross-domain problems.

Unlike an Engineering Manager, this role is not focused on people management. Instead, you will act as a technical leader and architectural reference, influencing multiple teams and ensuring long-term scalability, reliability, and engineering excellence.

You will thrive in a high-autonomy, fast-moving startup environment where technical decisions have direct product and business impact.

- Define and evolve fullstack architecture across frontend and backend systems.

- Lead complex system design initiatives, ensuring scalability, performance, and maintainability.

- Establish and enforce engineering standards and best practices.

- Drive technical alignment across teams.

- Contribute directly to critical parts of the codebase.

- Write scalable, production-ready, well-tested code.

- Lead major refactors and performance optimizations.

- Review code and provide deep technical guidance.

- Partner with Product and Engineering leaders to evaluate trade-offs between scalability, security, cost, and speed.

- Design APIs, database schemas, caching strategies, and distributed systems.

- Guide teams in handling edge cases, failure scenarios, and observability.

- Identify architectural bottlenecks and propose scalable improvements.

- Evaluate new technologies and frameworks.

- Improve system monitoring, instrumentation, and reliability practices.

- Extensive experience as a Senior Engineer, Principal Engineer, or Staff Engineer in fullstack environments.

- Strong frontend expertise in: React, Next.js and TypeScript

- Strong backend experience with: Golang and/or Python

- Deep experience designing distributed systems and scalable APIs.

- Strong knowledge of:

Data structures and algorithms

Design patterns

System design and architectural trade-offs

- Experience with AWS and cloud-native architectures.

- Experience with SQL and NoSQL databases.

- Strong debugging, refactoring, and performance optimization skills.

- Excellent written and verbal communication skills. Native or fluent English. Spanish is a plus.

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

Experience designing high-availability financial systems.

Exposure to compliance-sensitive or regulated environments.