Senior Software Engineer

Nelo•New York, NY

19h•Hybrid

About The Position

Nelo is building the credit layer that expands consumer buying power in Mexico. Currently, Nelo serves customers through credit cards, BNPL loans, bill payments, and its own marketplace. The company has achieved over $80M USD in annual revenue, secured more than $140M in equity and debt, and demonstrates significant scale and momentum. The team is described as lean, technical, and highly driven, comprising leaders and alumni from companies such as Uber, Amazon, Rappi, and DiDi. Nelo emphasizes speed, data-driven decisions, and quality, operating in Mexico City and New York City. This Senior Software Engineer role is presented as distinct from typical senior positions, offering a broad scope of work. It involves joining at a critical juncture where system importance and technical decisions are heightened, and the business operates at a real, non-hypothetical scale with live problems. The position is suited for individuals who wish to remain hands-on, collaborate with strong technical peers, and contribute to shaping the technical foundation of a rapidly growing company. The successful candidate will be deeply involved with code, architecture, and key product and business decisions.

Requirements

Strong backend fundamentals and real production experience
Experience in systems where reliability and scale matter, and knowing how to make good decisions in codebases with real constraints
5+ years of backend engineering experience
Strong distributed systems instincts
Solid judgment around performance, maintainability, and long-term technical quality
Comfortable with Kotlin and Spring, or can ramp quickly from a similar backend stack
Experience with AWS and Terraform
Thinking beyond the ticket, caring about how the whole system works
High ownership, operating without a lot of hand-holding, and comfortable speaking up when something feels off

Nice To Haves

Experience in fintech, payments, credit, marketplace, or other high-reliability environments
Experience at a fast-moving startup or growth-stage company
Experience with monolith-to-service evolution or other architecture transition work
Experience leading technically through design, implementation, and code review
Strong product instincts
Spanish fluency

Responsibilities

Build and improve backend systems that support core product experiences across credit, transactions, and marketplace infrastructure
Design for scale, reliability, performance, and data integrity as the business continues to grow
Help evolve a complex backend environment with sound judgment around architecture, service boundaries, and long-term maintainability
Raise the bar through strong implementation, thoughtful code review, and technical judgment that makes the team better
Partner closely with product, data, and engineering peers on high-impact technical and business problems
Use modern AI tools and workflows to move faster, think better, and increase engineering leverage