Steven Espinal
Verified Expert in Engineering
Full-stack Engineer and Developer
New York, United States
Toptal member since October 12, 2026
Steven is a full-stack engineer with six years of experience building revenue-focused products in eCommerce and regulated healthcare. At Thesis, an 8-figure DTC wellness brand, Steven drove more than $250,000 in incremental annual revenue through A/B testing and landing page optimization. He also shipped HIPAA-compliant software at BrightInsight and works primarily in React, Node.js, and TypeScript.
Portfolio
Experience
- Node.js - 7 years
- TypeScript - 7 years
- Git - 7 years
- Next.js - 7 years
- JavaScript - 7 years
- React - 7 years
- Shopify Hydrogen - 5 years
- PostgreSQL - 5 years
Preferred Environment
React, React Native, Next.js, Shopify, PostgreSQL, Claude API, Node.js, TypeScript, JavaScript
The most amazing...
...analytics pipeline I've built consolidated 356+ million live events into a single source of truth powering 12+ live dashboards and A/B test decisions.
Work Experience
Software Engineer
Thesis
- Drove over $250,000 in incremental annual revenue by designing and launching A/B tests on landing pages, product bundles, and cart optimization using GrowthBook, influencing roadmap decisions through data-driven insights.
- Led the migration of the analytics stack to a centralized Fivetran, Snowflake, and Amplitude pipeline, merging 356+ million events from Shopify, Recharge, and Klaviyo into a single source of truth powering 12+ live dashboards and A/B test decisions.
- Built custom Shopify REST API integrations connecting internal systems with 3rd-party services (Embeddables/analytics platforms), handling authentication and rate limiting across 10,000+ daily transactions and three product teams with 99.9% uptime.
Software Engineer
BrightInsight
- Improved patient data accessibility for clinicians by 30% by developing a React and TypeScript health portal that securely visualizes device metrics (e.g., diabetes, blood pressure) via interactive charts, enabling enhanced health monitoring.
- Optimized API request efficiency, cutting redundant data fetches by 70%, reducing server load and cloud costs by 35% across development, staging, QA, and production environments.
- Ensured regulatory compliance, i.e., audit readiness, and reduced future development time by 25% by authoring comprehensive technical documentation, including API specifications, system designs, and workflows, in Jama and Confluence.
Software Engineer
Cazton
- Increased platform flexibility by 35% within the first month by building a dynamic component rendering system driven by configuration files, laying the groundwork for multi-tenant features.
- Improved server query response time by 20% for the BrightInsight data microservice by partnering across QA, product, and back-end teams.
- Earned conversion from contract to full-time employee based on delivery speed and code quality on the BrightInsight platform.
Software Engineer
PLNETWORKS SRL
- Spearheaded a team of three engineers, improving feature delivery by 20% through rigorous code reviews, strategic technical roadmap discussions, sprint planning, and mentoring junior developers.
- Automated data entry workflows using Node.js, Google Vision AI, and Puppeteer, eliminating 30 hours of manual work per week, and enabling the creation of new data validation roles.
- Contributed to three new products by collaborating directly with the CTO on the full end-to-end development cycle.
Experience
Disease Management Solution
https://www.youtube.com/watch?v=1OreGEnAMBEEducation
Bachelor's Degree in Computer Science
Western Governors University - New York, NY, USA
Skills
Libraries/APIs
React, Node.js, Puppeteer, REST APIs, Claude API
Tools
Git, Claude Code, Confluence, Google Vision AI, Expo, Systemd, Shopify Plus
Languages
TypeScript, JavaScript, Java, GraphQL, SQL, Snowflake
Frameworks
Next.js, Shopify Hydrogen, React Native, Redux, Tailwind CSS
Storage
PostgreSQL, MongoDB
Paradigms
Microservices, Agile
Platforms
AWS IoT, Google Cloud Platform (GCP), Shopify, Klaviyo
Other
Algorithms, Data Structures, Operating Systems, Jama, Google Cloud Platform, WebSockets, Vite, GrowthBook, Fivetran, Amplitude, ReCharge, OAuth
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