Josh Choi
Verified Expert in Engineering
Full-stack Developer
New York, NY, United States
Toptal member since October 13, 2022
Josh is a Columbia-educated full-stack developer and founder who's spent 8+ years helping early-stage startups go from idea to launch. He builds React front ends, Node.js and Python back ends, and integrates everything from Stripe payments to Ethereum and Solana smart contracts—then deploys it all on AWS or GCP. He doesn't just write code; he ships products.
Portfolio
Experience
- React - 8 years
- Node.js - 8 years
- Python - 8 years
- SQL - 8 years
- TypeScript - 6 years
- Amazon Web Services (AWS) - 6 years
- Next.js - 6 years
- Solidity - 4 years
Preferred Environment
React, Node.js, Python, MongoDB, Amazon Web Services (AWS), Solidity, JavaScript, TypeScript, SQL, Next.js
The most amazing...
...team I've led was an experiment titled "The Effect of Microgravity on Chryseobacterium Aquaticum" that was sent to the International Space Station.
Work Experience
Founder
JCLVSH
- Built 20+ MVPs for early-stage startups since 2022.
- Developed and deployed full-stack products in React, Next.js, Node.js, and Python, integrating Stripe payments and Web3 services and shipping to AWS and GCP for clients.
- Led cross-functional product teams of up to 4 engineers, owning development cycles and delivering client projects on time.
Co-founder
CreatorGen
- Raised $500,000 from Alliance Accelerator and pitched in front of hundreds of investors for Demo Day.
- Co-founded an AI content-generation SaaS for creators, building the full-stack platform—React front end, Node.js, Express, and MongoDB back end—from zero to the launched product.
- Integrated five AI model APIs (OpenAI, Replicate, Fal AI, Runway ML, and ElevenLabs) to power hyper-realistic AI image, video, and text-to-speech generation for influencer campaigns.
Lead Full-stack Engineer
Vers
- Led the full-stack build of the Vers web platform and marketing site in Next.js, TypeScript, and PostgreSQL, taking a VM-branching product for AI agents from zero to launch in three months.
- Built the account and billing infrastructure end-to-end: GitHub OAuth via NextAuth, organization management, role-based access control, API-key issuance, and multi-tier subscription billing.
- Engineered an in-browser terminal emulator with Xterm.js and interactive 3D visualizations of live VM branch trees using Three.js and React Three Fiber.
Lead Full-stack Engineer
1848 Ventures LLC
- Built full-stack features across a consumer-facing Shopify extension, merchant admin portal, and the Vandra admin portal using React, Python, PostgreSQL, and the Shopify API.
- Engineered a data pipeline and H2O machine learning models that powered AI-driven discounting decisions for the Shopify extension.
- Automated order syncing, merchant performance analytics, and ML data pipelines by building a suite of microservices.
Senior React Developer
REITIUM Technologies Inc.
- Built the front end of a consumer-facing real estate investment platform using Next.js, TypeScript, and Tailwind CSS.
- Shipped core user-facing features: authentication, onboarding, and the full investment and payment flows.
- Collaborated in a three-person engineering team, delivering features on a one-week agile sprint cadence.
Experience
CreatorGen
https://creatorgen.ai/I developed the product end-to-end—a React front end (Zustand, Tailwind, Material UI) and a Node.js, Express, and MongoDB back end—and built the AI generation pipeline by integrating OpenAI, Replicate, Fal AI, Runway ML, and ElevenLabs for AI image, video, and text-to-speech output, with media stored and served via AWS S3. I also implemented the full SaaS business layer: Stripe subscription billing, a usage-based credit system, Web3 authentication through Privy, an admin dashboard, and a content marketplace. The platform was monitored with Sentry and PostHog and deployed on Heroku.
Vers
https://vers.sh/I developed the application end-to-end in Next.js, TypeScript, React, and PostgreSQL, building GitHub OAuth via NextAuth, organization management, role-based access control, API-key issuance, and multi-tier subscription billing. On the front end, I built two standout pieces: an in-browser web terminal emulator with Xterm.js and interactive 3D visualizations of live VM branch trees using Three.js and React Three Fiber, animated with Framer Motion and Lottie. I also shipped the marketing landing page, a blog system, and developer documentation, instrumented with PostHog analytics and covered by Playwright and Jest, all containerized with Docker.
Vandra
I also engineered the data and ML layer behind Vandra's core value: a data pipeline feeding H2O machine learning models that generated AI-driven discounting decisions in real time. To support it, I built a suite of microservices that automated order syncing, calculated merchant performance analytics, and managed the ML pipelines, giving merchants clear visibility into how dynamic discounting moved conversion and revenue.
REITIUM
https://reitium.com/I built the core member experience—email authentication, the investor dashboard, a marketplace for browsing and committing to private real estate and fixed-income deals, and a portfolio view for tracking holdings—wiring the front-end to back-end services through REST APIs and MongoDB. The result was a polished, trustworthy investing experience that let individuals discover, evaluate, and invest in offerings that were previously hard to access.
Education
Bachelor's Degree in Computer Science and Economics
Columbia University - New York, NY, USA
Skills
Libraries/APIs
React, Node.js, Scikit-learn, Web3.js, Puppeteer, NumPy, SciPy, X (formerly Twitter) API, jQuery, Vue, Matplotlib, REST APIs, Three.js, Playwright, Stripe
Tools
Figma, GitHub
Languages
JavaScript, TypeScript, Python, SQL, CSS, HTML, Solidity, PHP 7, PHP, GraphQL
Frameworks
Next.js, React Native, Flask, Bootstrap, NestJS, Redux, Express.js, Tailwind CSS, Jest, Agentic Frameworks
Storage
MongoDB, PostgreSQL, Databases, NoSQL, MySQL, Amazon DynamoDB
Paradigms
Automation, REST, Management
Platforms
Amazon Web Services (AWS), Ethereum, Google Cloud Platform (GCP), Blockchain, Shopify, Docker
Other
Full-stack, Front-end, Back-end, Back-end Development, Full-stack Development, Minimum Viable Product (MVP), APIs, User Experience (UX), User Interface (UI), Web & Mobile Applications, Web3, AI Agents, AI Tools, Prompt Engineering, Generative Artificial Intelligence (GenAI), Customer Research, Fundraising, Product Management, Web Marketing, Sales, Smart Contracts, DApps, Non-fungible Tokens (NFT), Decentralized Finance (DeFi), ERC-721, Decentralized Applications, Decentralized Autonomous Organizations (DAO), ERC-20, Freelancing, Product Development, API Integration, Artificial Intelligence (AI), Machine Learning, Business, Startups, Xterm.js, NextAuth.js, React Three Fiber (R3F), Large Language Models (LLMs), OpenAI, Content, AI Marketing, Agentic AI, Agentic AI Systems, Containerization, Leadership, Retrieval-augmented Generation (RAG)
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