# Leo Toff > Lead Software Engineer @ Capital One | Technical Founder | ex-Meta Location: San Francisco Bay Area, United States Profile: https://flows.cv/leotoff 10 years of backend, frontend, machine learning, and leadership experience. Leo has built, launched, and supported internal and external software products including web and mobile applications. Contributed to larger ongoing efforts in corporate and research environments. Tools used: Javascript/Typescript, Node, Postgres, Docker, AWS, Python, Kubernetes, FaunaDB, etc. ## Work Experience ### Lead Software Engineer @ Capital One Jan 2024 – Present | San Francisco Bay Area ### Lead Software Engineer @ Advisor Platinum Jan 2022 – Jan 2024 | San Francisco Bay Area - Built a SaaS web app for wealth management which simulates taxable cash flow and asset portfolios in various market conditions. Brought the idea from conception to MVP, and then to revenue. - Payments are processed by Stripe and then relayed through webhooks. Payments included metered billing. Customers manage billing through Stripe Customer Portal. - Set up container-based (Docker) infrastructure in AWS using ECS/Fargate, and Route 53, developed RESTful API in Node / Express.js which implements JWT-based authorization and persists to Postgres-compatible AWS Aurora. - Built web UI with React, Next.js, and AntD. Printing PDF reports which are designed with web standards and React. - Integrated with LLMs: entity classification with GPT-3.5, entity extraction with GPT-4, and WhatsApp-based language UI with fine-tuned GPT-3.5. Entity extraction is implemented with Python / FastAPI. - Built and published iOS and Android applications with React Native which includes authorization flow, the user’s inbox, and recording mic input which is then uploaded to AWS S3 with a pre-signed link. Mobile apps support offline operation including addition of new entries to the inbox. ### Software Engineer @ Facebook Jan 2021 – Jan 2021 | Burlingame, California, United States - Implemented multiple shelves in the Facebook newsfeed focused on various use cases of virtual reality including fitness, media, and social experiences with deeplinks into VR. This required Hacklang coding and coordination with dev relations, public relations, and privacy departments. - Built and launched people-you-may-know push notification in the mobile app and within virtual reality. The notif drove ~30\% increase in friend requests sent. - Built friend import UI in the new user experience flow on mobile in React Native ### Lead Software Engineer @ Advisor Platinum Jan 2019 – Jan 2021 | San Francisco Bay Area - built a SaaS tool for tax-optimized retirement planning and wealth management which implements IRS taxation logic for various income types and account types - implemented a delivery pipeline with prod, staging, and feature environments using Gitlab and Netlify following Gitlab Flow workflow - built a React/Gatsby Progressive Webapp (PWA) delivered via Netlify CDN, the app is installable on mobile and desktop devices, partial offline support - implemented infrastructure in AWS using ECS/Fargate, ECR, and Route 53 - developed RESTful API in Node (Loopback framework) with OpenAPI definition - leveraged D3.js and SVG for data visualization - implemented CPU-intensive computations of financial modeling on the client concurrently using web workers ### Software Engineer @ Promontory MortgagePath LLC Jan 2018 – Jan 2019 | Denver, Colorado - Set up Jenkins CI and release pipelines for Nx-based monorepo - Containerized Jenkins builds in Docker to improve resource utilization of the build servers - Led transition from Protractor/Selenium to Cypress integration testing engine - Implemented centralized repo for code styleguides to standardize coding conventions across projects - R&D'd and prototyped a Kubernetes cluster with Istio and Prometheus to demonstrate improved resource utilization, better flow of work, and consistency of the infrastructure ### Software Engineer, Team Lead/Liaison @ Arrow Electronics Jan 2016 – Jan 2018 | Denver, Colorado, United States - Managed the team's development and release pipelines through TeamCity and Octopus Deploy - Led the technical side of the Online-to-Offline initiative which included tracking of a multitude of user actions and pushing the data to Eloqua for data analysis, the initiative was projected to contribute $10M to revenue. It included Angular and Backbone development on the FE and C#/ASP.NET on the BE, data was pushed using RESTful API - Led technical side of GDPR compliance project which included Angular and C#/ASP.NET development - Integrated address management and payment methods management with Hybris which included Angular and C#/ASP.NET development - Updated look and functionality of the payment methods management dashboard - Integrated Arrow web properties with Indiegogo API including its campaign, collections APIs etc. which included Angular, Backbone, and C#/ASP.NET development ### Software Engineer, Web Lead @ OneUni, Inc. Jan 2015 – Jan 2016 | San Francisco Bay Area - Implemented images and video uploading/downloading logic to AWS S3 in Android app using AWS pre-signed URLs for PUT and GET requests - Managed UI team's development and release pipelines in AWS - Fixed significant delays in the Android app's initialization pipeline by finding its source in Twilio SDK, and then working closely with Twilio IP Messaging team to achieve results - Developed a React/Redux chat web application that allowed external students of our platform communicate with the internal team of coaches; used Twilio IP Messaging - Established web team’s technology stack as React/Redux/Webpack/ES6/Babel/ESLint early on based on business requirements from the management team; the chosen technologies proved to deliver a high-quality product - Worked with the Android team on developing our flagship Android application, focused on video playback, messaging, and social sharing ### Software Engineer @ Vixlet Jan 2014 – Jan 2015 | Los Angeles, CA - Created a webapp for managing users, used Node and ExpressJS for the API and React for the frontend. Used OAuth for authentication and MongoDB to store data - Analyzed data in order to understand user dynamics (conversion and retention) and user demographics using MapReduce in MongoDB ## Education ### Master's degree in Electrical Engineering National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) Jan 2007 – Jan 2013 ## Contact & Social - LinkedIn: https://linkedin.com/in/toff --- Source: https://flows.cv/leotoff JSON Resume: https://flows.cv/leotoff/resume.json Last updated: 2026-03-22