Oscar – React, Typescript, Golang

An AI-powered CRM for legal and operations teams to manage cases, consolidate client communications, and automate document preparation. Its main features included case-aware AI assistance, declaration generation from client interviews, and sentiment analysis to flag cases needing attention.

• Worked as Principal Engineer in a three-person squad within a ~12-person engineering team, owning architectural decisions while staying hands-on in production code, AI orchestration, model evaluation, CI/CD, developer tooling and observability.
• Built the declaration evaluation framework, combining custom AI judges with deterministic checks for factual accuracy.
• Co-designed the AI declaration-generation architecture: facts are extracted and prioritized from 3–4-hour interview transcripts before generation, and the same factual representation serves as the evaluation contract, improving coverage and reducing hallucinations.
• Defined a model-evaluation strategy that combined golden datasets, automated judges, factual checks and human expert review, helping raise preparation capacity from 2–3 to 10–20 declarations per person per day.
• Created a reusable AI-native delivery harness that guides coding agents from requirement clarification and planning through TDD, adversarial review, e2e testing, PR generation, static analysis and CI validation.
• Designed Global Search on PostgreSQL instead of Elasticsearch, trading future scaling headroom for lower infrastructure complexity, simpler synchronization and fewer failure modes at the system's actual scale.

A fintech focused on credit and working capital for small merchants in Mexico and the Dominican Republic.

• Architected the evolution from an externally developed monolith to approximately 30 domain-oriented services, using REST, asynchronous processing, Google Cloud Tasks, PostgreSQL, Redis, and independently deployable Cloud Run workloads.
• Personally designed core lending workflows including onboarding, KYC, credit lines, disbursements, payments, collections, reconciliation, risk, and fraud controls, with particularly deep implementation involvement in KYC, lending, payment flows, and financial integrations.
• Helped design and productionize underwriting pipelines combining computer vision-based inventory estimation, merchant purchase data, deterministic financial models, and risk/fraud scoring to determine eligibility and credit conditions.
• Designed Cloud Run-based infrastructure that kept cloud expenditure around US$2K/month or less while supporting ~30 services and ML workloads.
• Introduced financial-correctness controls around interest, balances, statements, and cent-level precision.
• Built and operated a platform supporting approximately 3,000 merchants, US$5M in cumulative disbursements, US$1.5M peak portfolio, and >99% availability across Mexico and the Dominican Republic.

An online grocery platform that enabled customers to shop for groceries and have them delivered to their homes.

• Served as the primary software architect for ~50 developers during the modernization of a legacy PHP platform toward Go and AWS.
• Designed and validated centralized authentication with AWS Cognito, including account migration, coexistence with legacy systems and Go/Lambda integration patterns.
• Reviewed and approved technical designs and resolved cross-team architectural issues.
• Defined engineering and architecture standards together with the Head of Engineering.
• Built Go proofs of concept to validate new platform patterns.
• Evaluated serverless and managed-service approaches to reduce infrastructure complexity, resource consumption and reliance on vertical scaling while staying compatible with the existing platform.

A payments and card-tokenization platform supporting transaction approval, risk evaluation, and secure payment credentials.

• Worked as a software architect across multiple teams in payments and financial technology, defining architecture, engineering standards and solution designs for client and product initiatives, using Java, Spring and microservices.
• Reviewed technical designs and produced architecture definitions, PoCs, technical reviews and delivery estimates.
• Led requirements workshops and architecture design for a card-tokenization solution for a major retailer, enabling saved payment credentials, faster checkout and recurring payments (discovery and architecture phase, before full implementation).
• Contributed to scalability and architecture improvements for transaction-approval and risk-processing components in the payments platform.
• Took part in selected client workshops and presales/estimation activities where architectural discovery was needed.

A web and mobile banking platform that enabled customers to view balances and transaction history, check credit limits, and block or reactivate cards, later expanding to debit and savings accounts.

• Provided technical leadership as a Fullstack Lead Engineer in a ~20–30-person initiative modernizing web and mobile transactional banking for roughly 1M credit-card users; the team delivered the initial credit-card pilot in about six months.
• Combined hands-on development (Java, Spring, Angular) with technical design, engineering standards and guidance.
• Helped design the facade and integration architecture connecting modern REST-based digital channels to the legacy SOAP banking core.
• Designed domain-oriented service boundaries and anti-corruption layers to isolate legacy models from the new platform.
• Co-designed rule-based step-up authentication using incremental JWT claims, enabling transaction-specific authentication requirements.

A multinational billing and invoicing platform designed to support approximately 10 countries, with multiple currencies, tax requirements, and country-specific billing rules.

• Worked as a Software Engineer III (backend) on payment and financial systems, primarily with Java, Spring and microservice-based architectures.
• Designed and implemented parts of a configurable billing/settlement platform supporting ~10 countries, including multiple currencies, tax structures and jurisdiction-specific invoicing rules, without duplicating the platform for each country.
• Built bank-transfer functionality and internal tools for managing transfers, merchants, customers and operational workflows.
• Contributed to team engineering practices using BDD and agile development.