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.