Alex Kates

alexkates.dev | daniel.alexander.kates@gmail.com | Philadelphia, PA
Full-Stack Engineer | TypeScript, Next.js, Expo, AWS, Supabase

Profile

Full-Stack Engineer with 15 years of experience building products for fintech and e-commerce startups. Founding engineer at Croissant, Credit Genie, and Swift Capital (acquired by PayPal). I design and build reliable applications across web, mobile, and browser extensions using TypeScript, React, Next.js, React Native, Expo, Plasmo, and AWS Serverless and Supabase. I regularly use AI coding agents such as GitHub Copilot and Claude to move faster, improve code quality, and focus on product outcomes.

Skills

TypeScript, React, React Native, Next.js, Expo, Plasmo, shadcn/ui, Tailwind, Nativewind, Unistyles, Framer Motion, React Query, Zustand, Zod, Reanimated, AWS Lambda, API Gateway, AppSync, DynamoDB, EventBridge, SQS, S3, Supabase, GitHub Copilot, Claude, ChatGPT, VS Code, AWS CDK

Experience

Founding Engineer @ Croissant

Jun 2022 – Present
Croissant helps shoppers get more value from their purchases through Guaranteed Buybacks and Cashback rewards.

  • Built Croissant’s Chrome extension, iOS app, and website using Next.js, Expo, Plasmo, React, and React Native supporting thousands of resale orders and shopping sessions each month.
  • Maintained Croissant’s API and database systems using AWS Serverless (Lambda, API Gateway, AppSync, DynamoDB, EventBridge, SQS, S3) and integrated Stripe, PayPal, Venmo, EasyPost, and Shopify.
  • Created an internal Resale Ops platform in Retool that helps three warehouses and 10+ resellers inbound, quality review, and list products valued at millions in annual GMV.
  • Integrated PostHog analytics to track user behavior, funnels, and conversion rates to support customer service and inform product decisions.

Founding Engineer @ Credit Genie

Dec 2019 – Mar 2022
Credit Genie helps consumers reduce credit-card debt, manage expenses, and build credit.

  • Built Credit Genie's mobile and web apps with Next.js, Expo, React, and React Native supporting thousands of users managing their credit and finances.
  • Built Credit Genie's serverless backend on AWS (AppSync, Lambda, API Gateway, DynamoDB, S3) and integrated Plaid and TransUnion for financial data.
  • Created an ACH processing system that handled millions in transactions each year.

Senior Software Engineer @ LoanBuilder

Mar 2016 – Dec 2019
LoanBuilder helped small business owners access working capital online and was later acquired by PayPal in 2017 to power its Business Lending platform.

  • Built and maintained the LoanBuilder.com application using AngularJS and ASP.NET WebAPI, enabling customers to apply for and manage loans entirely online.
  • Scaled the product to support hundreds of millions of dollars in funding across thousands of small business loans.
  • Integrated with TransUnion, Equifax, and Plaid to automate credit checks, bank verification, and risk assessment.
  • Collaborated with product and design teams to improve loan flows and post-acquisition expansion within PayPal's lending ecosystem.

Earlier Experience

Senior Software Engineer @ InvestorForce / MSCI (2014 – 2016) – Developed risk-analytics apps and APIs for investment managers.
Senior Software Engineer @ Algorithmics (IBM) (2011 – 2014) – Built desktop and API tools for enterprise collateral management.
Software Developer @ Susquehanna International Group (2010 – 2011) – Developed internal apps and APIs for market-data services.

Education

Bachelor of Science in Computer Science — Drexel University, Philadelphia, PA
Awards: Drexel Academic Scholarship and Grant

Last updated: November 2025