Alex Kates

Professional Summary

Full-Stack Engineer with 15 years of experience building fintech and e-commerce products as founding engineer at Croissant, Credit Genie, and Swift Capital (acquired by PayPal). Design and build reliable web, mobile, and browser-extension applications with TypeScript, React, Next.js, React Native, Expo, and serverless APIs using AWS and Supabase. Use AI coding agents including GitHub Copilot and Claude to ship faster with higher code quality.

Technical Skills

Languages: TypeScript, JavaScript, SQL Frontend / Web: React, Next.js, Tailwind CSS, shadcn/ui, Framer Motion, React Query, Zustand, Zod Mobile: React Native, Expo, Reanimated, NativeWind, Unistyles Browser Extensions: Plasmo Backend / APIs: Node.js, REST APIs, GraphQL (AWS AppSync), AWS Lambda, API Gateway, DynamoDB, EventBridge, SQS, S3, Supabase (Postgres, Auth, RLS) Cloud / IaC: AWS Serverless, AWS CDK Integrations: Stripe, PayPal, Venmo, Plaid, TransUnion, Equifax, EasyPost, Shopify, PostHog Tools / AI: GitHub, VS Code, GitHub Copilot, Claude, ChatGPT, Retool

Professional Experience

Founding Engineer @ Croissant

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

Architected Croissant's Chrome extension (Plasmo), iOS app (Expo, React Native), and web app (Next.js, React) supporting thousands of resale orders and shopping sessions per month.
Design and operate Croissant's serverless API and data platform on AWS (Lambda, API Gateway, AppSync GraphQL, DynamoDB, EventBridge, SQS, S3), integrating Stripe, PayPal, Venmo, EasyPost, and Shopify for payments, payouts, and fulfillment.
Built Resale Ops platform in Retool used by 3 warehouses and 10+ resellers to inbound, quality-review, and list inventory driving millions in annual GMV.
Implemented PostHog product analytics across funnels and conversion events to inform product decisions and support customer-service investigations.

Founding Engineer @ Credit Genie

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

Shipped Credit Genie's mobile and web apps with Expo, React Native, React, and Next.js serving thousands of users managing credit, expenses, and savings.
Designed serverless backend on AWS (AppSync GraphQL, Lambda, API Gateway, DynamoDB, S3) and integrated Plaid and TransUnion for bank connections and credit data.
Built ACH payments system processing millions in transactions per year for debt-paydown and savings flows.

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.

Developed LoanBuilder.com origination and servicing flows with AngularJS and ASP.NET WebAPI, enabling customers to apply for and manage loans entirely online.
Scaled platform to support hundreds of millions in funded volume across thousands of small-business loans.
Automated credit checks, bank verification, and risk assessment via TransUnion, Equifax, and Plaid integrations.
Partnered with product and design to improve application conversion and support 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