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Nathaniel Finger
Verified Expert in Engineering
React Developer
Mansfield, MA, United States
Toptal member since March 31, 2022
Bio
Nathaniel is a senior full-stack engineer with 9+ years of experience building scalable apps for DraftKings, Webflow, and fintech startups. He led teams of 30+ developers, reduced load times by 75%, and delivered products serving millions of users. He specializes in React, Node.js, and cloud architecture, transforming complex requirements into smart solutions. His proven track record of shipping ahead of schedule while mentoring teams makes him the ideal partner for ambitious technical projects.
Portfolio
DraftKings
TypeScript, React, Next.js, C#, Technical Leadership, Leadership, HTML, CSS...
Capybara Intelligence Incorporated
Python, AI Model Training, Back-end, WebSockets, Amazon Web Services (AWS)...
Reggora
React, Python, Flask, MongoDB, Technical Leadership, Amazon Web Services (AWS)...
Experience
- Python - 7 years
- React - 7 years
- Node.js - 6 years
- MongoDB - 6 years
- TypeScript - 6 years
- Flask - 6 years
- GraphQL - 4 years
- Next.js - 2 years
Preferred Environment
MacOS, Visual Studio, Slack, Zoom, Google Meet
The most amazing...
...accomplishment was delivering DraftKings' Pick6 platform in four months instead of six, saving $2 million while handling millions of daily users.
Work Experience
Senior Lead Software Engineer
2021 - PRESENT
DraftKings
- Accelerated mobile app delivery. Led a cross-functional team of four developers to deliver a white-label mobile application two months ahead of schedule (four months vs six months), maintaining quality standards and budget constraints.
- Launched the Pick6 gaming platform. Directed the frontend development team to successfully launch the Pick6 gaming platform within an aggressive 4-month deadline, ensuring on-time delivery for millions of daily fantasy sports users.
- Built and mentored an engineering team from 4 to 10 developers, establishing coding standards and technical review processes that improved code quality across the organization.
- Established a knowledge-sharing culture. Created and facilitated monthly company-wide technology forums, leading knowledge sharing initiatives across 50+ engineering staff and fostering collaborative learning.
- Delivered NFT marketplace features. Architected and supervised technical implementation of candle auction functionality for NFT marketplace, managing full development lifecycle from planning through deployment.
- Improved application performance. Led strategic migration from client-side to server-side rendering frameworks across all new product verticals, improving application performance by 50% and SEO capabilities.
- Enhanced operational efficiency. Redesigned internal operations tooling information architecture, streamlining workflows and improving user interface design to increase team productivity by 30%.
Technologies: TypeScript, React, Next.js, C#, Technical Leadership, Leadership, HTML, CSS, Web3.js, Apollo, Software Architecture, Decentralized Finance (DeFi), User Interface (UI), Front-end, GitHub, JavaScript, Front-end Development, REST, ECMAScript (ES6), OpenAI API, Agentic Frameworks, LangChain
Experienced Back-end Engineer
2025 - 2025
Capybara Intelligence Incorporated
- Developed proprietary AI algorithms to generate engaging social media content.
- Tracked and refined tickets using Linear. Created scalable DevOps practices using infrastructure as code.
- Oversaw critical development processes leading to a successful app store launch.
Technologies: Python, AI Model Training, Back-end, WebSockets, Amazon Web Services (AWS), Node.js, Multimedia, Large-scale Distributed Systems
Head of Engineering Enablement
2018 - 2021
Reggora
- Restructured our monolithic API into faster, more resilient microservices.
- Oversaw the development of countless full-stack features, including the order management system and job allocation algorithm.
- Implemented a payment management system and integration with stripe.
Technologies: React, Python, Flask, MongoDB, Technical Leadership, Amazon Web Services (AWS), Leadership, HTML, CSS, Apollo, Software Architecture, User Interface (UI), Front-end, Redux, GitHub, Styled-components, JavaScript, Front-end Development, REST, ECMAScript (ES6)
Lead Developer
2015 - 2018
Gemr
- Lead the conversion of a JavaScript application to an end-to-end TypeScript application.
- Manage sprint planning, allocation of time and resources, and significant feature planning.
- Coordinated the contributions of a team of several offshore engineers.
Technologies: Angular, Express.js, MongoDB, TypeScript, Node.js, Technical Leadership, Leadership, HTML, CSS, User Interface (UI), Front-end, Redux, GitHub, Styled-components, JavaScript, Front-end Development, REST, ECMAScript (ES6)
Experience
Full-stack Developer—Visual Web Development Platform
https://webflow.com• Contributed to Webflow's no-code website builder as a full-stack developer, focusing on dashboard features and payment systems.
• Developed React components for the user dashboard, implementing real-time project management features and analytics visualizations.
• Built payment integration with Stripe, handling subscription workflows, usage-based billing, and invoice generation for thousands of customers.
• Implemented comprehensive test coverage using Jest and Cypress, achieving 85% coverage on new features.
• Optimized dashboard performance through lazy loading and data virtualization, reducing load times by 40%.
• Collaborated with design teams to deliver pixel-perfect UI implementations while maintaining accessibility standards.
• Built Node.js APIs supporting dashboard features with caching strategies for high-frequency requests. This experience deepened my expertise in SaaS platforms and real-time collaboration features.
• Developed React components for the user dashboard, implementing real-time project management features and analytics visualizations.
• Built payment integration with Stripe, handling subscription workflows, usage-based billing, and invoice generation for thousands of customers.
• Implemented comprehensive test coverage using Jest and Cypress, achieving 85% coverage on new features.
• Optimized dashboard performance through lazy loading and data virtualization, reducing load times by 40%.
• Collaborated with design teams to deliver pixel-perfect UI implementations while maintaining accessibility standards.
• Built Node.js APIs supporting dashboard features with caching strategies for high-frequency requests. This experience deepened my expertise in SaaS platforms and real-time collaboration features.
Senior Frontend Engineer - Loan Operations Platform
Developed features for Sirvatus's loan operations platform as a Senior Frontend Engineer, building tools that give direct lenders centralized control over their loan portfolios. Led the implementation of real-time portfolio dashboards using Next.js and TypeScript, enabling loan operations teams to track thousands of loans across their lifecycle stages.
Built responsive UI components with React and Tailwind CSS, focusing on data-heavy interfaces that display complex loan metrics, payment schedules, and borrower information. Implemented real-time updates using WebSockets to ensure loan officers always had current data. Optimized performance for large datasets through virtualization and pagination strategies, handling portfolios with 10,000+ active loans.
Collaborated with product and design teams to transform fintech compliance requirements into intuitive user workflows. Wrote comprehensive test suites achieving 90% coverage, crucial for financial software reliability. Documented coding standards and established best practices for the growing engineering team.
This engagement deepened my expertise in fintech applications and reinforced my ability to build performant, data-intensive interfaces for regulated industries.
Built responsive UI components with React and Tailwind CSS, focusing on data-heavy interfaces that display complex loan metrics, payment schedules, and borrower information. Implemented real-time updates using WebSockets to ensure loan officers always had current data. Optimized performance for large datasets through virtualization and pagination strategies, handling portfolios with 10,000+ active loans.
Collaborated with product and design teams to transform fintech compliance requirements into intuitive user workflows. Wrote comprehensive test suites achieving 90% coverage, crucial for financial software reliability. Documented coding standards and established best practices for the growing engineering team.
This engagement deepened my expertise in fintech applications and reinforced my ability to build performant, data-intensive interfaces for regulated industries.
Japanese Soccer League NFT Marketplace
An NFT marketplace for the Japanese soccer league. I was the lead developer on this project and oversaw all planning and development of the project. This included coordinating with developers across time zones and working with a company that spoke mainly Japanese.
Genies
http://genies.comAn NFT Marketplace selling digital avatar accessories. This application is built using Next.js and Go. I was the Technical Architect and Lead Developer on this project. This project interacts with the Flow blockchain to store and read crucial data.
Education
2012 - 2016
Bachelor's Degree in Mathematics
University of Connecticut - Storrs, Connecticut, USA
Skills
Libraries/APIs
React, Node.js, OpenAI API, Web3.js
Tools
GitHub, Zoom, Visual Studio, Slack, Google Meet, Flow, Prisma
Languages
TypeScript, Python, GraphQL, HTML, CSS, JavaScript, ECMAScript (ES6), C#, Go, Rust, Fortran, SQL
Frameworks
Next.js, Express.js, Redux, Flask, Angular, Jest, Cypress, Agentic Frameworks
Paradigms
REST
Platforms
MacOS, Amazon Web Services (AWS), Vercel
Storage
MongoDB, PostgreSQL
Other
Technical Leadership, User Interface (UI), Front-end, Front-end Development, Leadership, Apollo, Software Architecture, Styled-components, Differential Equations, Calculus, Stochastic Modeling, Decentralized Finance (DeFi), QA Testing, Flux Architecture, Full-stack, LangChain, AI Model Training, Back-end, WebSockets, Multimedia, Large-scale Distributed Systems
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