Sandra L.
Senior Backend Engineer
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Sandra G. is a seasoned Senior Backend Engineer with over 15 years of industry experience specializing in the development of scalable, cloud-native systems leveraging Kotlin and Java. Currently focused on AI systems, she excels in crafting structured problem definitions and evaluation workflows, ensuring the reliability and validation of non-deterministic systems. At Mercor, Sandra designed comprehensive evaluation rubrics and developed knowledge bases to streamline AI solution generation. Her prior role at ClassPass involved leading efforts in implementing event-driven architectures and optimizing REST APIs, significantly enhancing processing capabilities and system reliability. With a strong background in cloud deployments and technical leadership, Sandra has a proven track record of driving architecture decisions and synchronizing cross-functional teams. She holds a Bachelor's Degree in Computer Science from Instituto Tecnológico de Toluca, and her technical skillset includes expertise in AWS, SQL, and BPM-driven microservices.
Experience
Senior Backend Engineer
Mercor Contractor · 2026 — PresentDesigned structured problem definitions for AI coding agents that connected real-world pull requests with executable specifications. Defined technical requirements and interfaces, enabling the generation of verifiable solutions. Developed comprehensive evaluation rubrics in JSON for assessing functional correctness and system robustness. Validated AI-generated solutions within containerized environments, addressing non-deterministic behavior, and guiding agents toward correct implementations. Built knowledge bases for capturing design decisions and system behaviors. Created evaluation trajectories to assess agent reasoning with decision checkpoints. Utilized AI-assisted tooling, including Cursor, Claude, and Gemini, to enhance workflows.Senior Software Engineer
ClassPass · 2021 — 2025Engineered event-driven backend systems using AWS SNS/SQS for scalable processing and failure isolation. Led the transformation of key systems into event-driven architectures, employing S3 and distributed workers. Developed and enhanced REST APIs in Kotlin/Java for both internal and external integrations, ensuring backward compatibility and robust error handling. Established reliability patterns for third-party integrations to reduce alert noise. Designed relational data models supporting payments and invoicing, optimizing performance through query tuning. Functioned as Tech Lead, guiding architecture decisions and aligning teams. Improved observability through refined monitoring and alerting practices.Senior Developer
Nokia (HCL / IT Seekers) · 2018 — 2020Contributed to the Nokia SMP platform by designing and implementing Java-based backend components that integrated with BPMN-driven workflows. Built REST-based integrations and service tasks, ensuring reliability in long-running processes. Modeled BPMN workflows and maintained JUEL expressions to enhance process robustness and throughput.Senior Developer
Solcom Mexico · 2015 — 2018Created software solutions for an online personal banking application with a focus on scalability. Developed and maintained backend services utilizing Java J2EE with Spring MVC to ensure high performance.Senior Software Engineer & Tech Lead
CocaCola Femsa, HSBC, BofA, HP, Banco del Bajío · 2008 — 2015Developed enterprise solutions with Java and Python, enhancing SOA capabilities. Built robust web services through meticulous code reviews and efficient database design. Streamlined ETL processes and utilized UML for improved data management.
Skills & Expertise
Education
- Bachelor’s Degree in Computer Science & Engineering (Database Specialty)Instituto Tecnológico de Toluca