James Essex

Senior Full Stack Software Engineer III at Blue Origin, LLC

Architected and maintained shared React and TypeScript component libraries within an Nx monorepo; established scalable UI standards across internal platforms; delivered high-availability solutions for a large distributed organization; led frontend modernization and backend integration with distributed services.

Senior Full Stack Software Engineer IV at Zipcar, Inc.

Led end-to-end onboarding system redesign, integrating identity verification and fraud decisioning to deliver secure signup workflows while reducing verification costs from $24 to $8 per signup; developed backend services in Ruby on Rails with Postgres to support risk-based decision engines.

Front End Software Developer at CitiGroup

Delivered enterprise-grade Angular features across Citi Bank Online and the D10X platform; migrated legacy AngularJS to a modern Nx monorepo-based architecture; improved data fetch efficiency and API contracts across microservices.

Co-Founder / CFO at Secret Serums Skin Care (aka Sera Labs, Inc.)

Co-founded and scaled a direct-to-consumer ecommerce brand to $16.2M+ revenue in 29 months; designed and automated financial auditing and cash-flow reconciliation workflows; implemented merchant processing infrastructure; developed forecasting models and collaborated with marketing and product teams to optimize landing pages and partnerships.

Front End Software Developer at Citigroup – CBO L Team & D10X (Contractor through TCS)

Delivered enterprise-grade Angular features across Citi Bank Online (CBO L), Citi Ventures fintech products, and the D10X shared platform. Built modular Angular applications using Ng-Core and Nrwl Nx monorepo architecture to improve code reuse, scalability, and cross-team consistency. Enhanced front-end performance by refactoring legacy components, improving accessibility, and ensuring cross-browser compatibility. Collaborated with data and backend teams to optimize data fetching and API contracts; mentored junior engineers and contributed to CI/CD pipelines.

Co-Founder / CFO at Secret Serums Skin Care (Sera Labs, Inc.)

Co-founded a direct-to-consumer e-commerce brand and scaled to $16.2M+ revenue in 29 months. Led financial strategy, operations, and data-driven growth initiatives; designed automated financial auditing and cash-flow reconciliation workflows using Python and Excel VBA, boosting reporting accuracy and reducing manual effort. Implemented merchant processing infrastructure to support multi-million-dollar credit card volumes, stabilized reconciliations across channels, and improved margin management. Built forecasting and budgeting models to guide inventory procurement and vendor negotiations. Collaborated with marketing and product teams to optimize landing pages and tracking, driving measurable revenue growth; developed internal CRM and tooling for near real-time customer/account management and enhanced support. Strengthened fraud prevention with validation and authentication improvements and translated product/security constraints into scalable production releases.

Smart Contract Engineer at Tangentblock.io

Built Solidity smart-contract-based infrastructure for Tangible Realty’s real estate/tokenization concept as an enterprise solution enabling loan-based asset vehicles and secure on-chain workflows for real-estate-backed tokens.

Data Pipeline Automation (ETL) at Secret Serums Skin Care (Sera Labs, Inc.)

Python-based ETL automation extracting from SQL sources and web scraping, transforming datasets, and producing CSV outputs for Excel-based financial reporting and reconciliation.