Sr. Backend Engineer

About the Role

We're looking for a Senior Backend Engineer to independently own features and deliver high-quality backend systems. You'll take projects from spec to production, write code that others want to work with, and help mentor newer engineers.

At this level, you're a reliable, autonomous contributor—you can scope and ship features end-to-end with minimal guidance and proactively unblock yourself and others.

What You'll Do

• Own features end-to-end — Scope, design, build, test, and ship features independently

• Write quality code — Deliver clean, testable, well-documented code with strong testing discipline

• Unblock the team — Proactively help teammates debug issues and remove blockers

• Handle on-call — Confidently respond to incidents using observability tools

• Mentor newer engineers — Support E1s through pairing, onboarding, and code review

• Leverage AI daily — Use AI tools to accelerate coding, debugging, testing, and learning

• Pay down tech debt — Identify and fix issues that slow the team down

What We're Looking For

Technical

• 3+ years building backend systems

• Strong experience with Java (Python/Go a plus)

• Good understanding of distributed systems, APIs, and cloud infrastructure

• Strong testing discipline—unit tests, integration tests, edge cases

• Systematic debugging skills across service boundaries

AI Fluency

• Uses AI tools (Copilot, Claude, ChatGPT) daily for coding, debugging, and test generation

• Builds reusable prompts or workflows that help the team

• Teaches effective AI usage to junior engineers

• Curious about new AI capabilities relevant to backend development

Communication

• Writes clear design docs and runs small design discussions

• Gives and receives direct, timely feedback

• Fluent in Spanish; working knowledge of English for cross-team collaboration

Mindset

• Self-directed; you don't wait to be told what to do

• Comfortable with ambiguity and changing requirements

• Product-minded—you care about business outcomes, not just code

Nice to Have

• Experience in fintech, payments, or lending

• Familiarity with our stack: AWS (ECS, Lambda), PostgreSQL, Kafka, DataDog

• On-call and incident response experience

• Understanding of the Mexican fintech ecosystem (BNPL, credit, regulation)

Our Stack

Java (primary), Python, Go · AWS (ECS, Lambda) · PostgreSQL · Kafka · DataDog · Pulumi · Jenkins

Why Aplazo

Our mission is to empower financial access and opportunity across Latin America through fair, simple, and transparent solutions. Our tech vision: be the most beloved and innovative tech organization in Latin America.

We're a Series B fintech growing fast—you'll have real ownership, impact, and the chance to shape how millions of people access credit.