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. Pro Tip: How do we review your CV? Help us find you! We filter applications with the help of AI. To ensure your profile is properly evaluated, we recommend describing your experience using the keywords from this job posting. #Ly-remote Personal data collected during the recruitment process will be processed in accordance with the Privacy Notice of Aplaz, S.A. de C.V. (“Aplazo”), available at our Privacy and Policy Notice https://aplazo.mx/privacy-and-policy. Aplazo does not discriminate on the basis of race, religion, skin color, sex, gender, age, ethnic or national origin, marital status, disability, social or economic status, sexual preferences, or any other condition or characteristic. Selection is based solely on the qualifications and merits of the candidates. #LI-Remote