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Full-stack software engineer with 12 years of experience building reliable web applications, SaaS products, backend APIs, and production systems using TypeScript, React, Next.js, and modern cloud platforms. Focused on maintainable architectures, responsive mobile-first UX, strong security, and dependable delivery. Experienced integrating OpenAI capabilities with structured outputs and validation, and implementing SaaS payments/subscriptions (Stripe), authentication/authorization, analytics, and production deployment through Vercel and GitHub. Comfortable owning end-to-end features from requirements and database design through testing, monitoring, and iteration.…Full-stack software engineer with 12 years of experience building reliable web applications, SaaS products, backend APIs, and production systems using TypeScript, React, Next.js, and modern cloud platforms. Focused on maintainable architectures, responsive mobile-first UX, strong security, and dependable delivery. Experienced integrating OpenAI capabilities with structured outputs and validation, and implementing SaaS payments/subscriptions (Stripe), authentication/authorization, analytics, and production deployment through Vercel and GitHub. Comfortable owning end-to-end features from requirements and database design through testing, monitoring, and iteration.

Karol Piotrowski

Full Stack Developer, Web Developer, Back-End Developer, +2

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Full-stack software engineer with 12 years of experience building reliable web applications, SaaS products, backend APIs, and production systems using TypeScript, React, Next.js, and modern cloud platforms. Focused on maintainable architectures, responsive mobile-first UX, strong security, and dependable delivery. Experienced integrating OpenAI capabilities with structured outputs and validation, and implementing SaaS payments/subscriptions (Stripe), authentication/authorization, analytics, and production deployment through Vercel and GitHub. Comfortable owning end-to-end features from requirements and database design through testing, monitoring, and iteration.…Full-stack software engineer with 12 years of experience building reliable web applications, SaaS products, backend APIs, and production systems using TypeScript, React, Next.js, and modern cloud platforms. Focused on maintainable architectures, responsive mobile-first UX, strong security, and dependable delivery. Experienced integrating OpenAI capabilities with structured outputs and validation, and implementing SaaS payments/subscriptions (Stripe), authentication/authorization, analytics, and production deployment through Vercel and GitHub. Comfortable owning end-to-end features from requirements and database design through testing, monitoring, and iteration.

Available to hire

Full-stack software engineer with 12 years of experience building reliable web applications, SaaS products, backend APIs, and production systems using TypeScript, React, Next.js, and modern cloud platforms. Focused on maintainable architectures, responsive mobile-first UX, strong security, and dependable delivery.

Experienced integrating OpenAI capabilities with structured outputs and validation, and implementing SaaS payments/subscriptions (Stripe), authentication/authorization, analytics, and production deployment through Vercel and GitHub. Comfortable owning end-to-end features from requirements and database design through testing, monitoring, and iteration.

Skills

Experience Level

Expert

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Expert

Work Experience

Senior Full-Stack SaaS Developer at Consensys

June 1, 2021 - Present

Architected production-grade web applications with Next.js, TypeScript, and React, emphasizing straightforward boundaries, responsive interfaces, and maintainable full-stack ownership. Engineered reusable frontend experiences with Tailwind CSS, component-driven architecture, responsive layouts, and accessibility practices. Integrated backend APIs through Next.js server capabilities with validation, authorization, structured error handling, and secure request processing for SaaS workflows. Modeled relational data with PostgreSQL (normalized schemas, indexes, constraints). Implemented authentication/authorization with Supabase Auth and Row Level Security. Connected OpenAI capabilities using structured outputs, schema validation, deterministic parsing, and human confirmation steps before persisting AI-derived information. Built subscription/entitlement workflows with Stripe, including checkout, recurring billing, webhook processing, and account/payment synchronization. Deployed through

Software Engineer at UCB

June 1, 2018 - April 1, 2021

Built scalable web interfaces with React and TypeScript, delivering responsive experiences using reusable components and predictable application behavior. Designed RESTful backend services and API contracts separating presentation from business logic. Refactored relational database structures and SQL queries in PostgreSQL to improve maintainability and performance. Established authentication and authorization controls across endpoints with secure session handling, permission checks, validation, and defense-in-depth. Introduced automated testing (unit, integration, API) to increase confidence and shorten feedback cycles. Streamlined deployment using GitHub source control and automated build workflows. Integrated third-party services via authenticated APIs and webhooks with retry handling, payload validation, idempotency protections, and failure recovery. Improved frontend responsiveness via rendering/state optimization and reduced avoidable client-side processing. Coordinated migratio

Software Developer at Razor Inc

March 1, 2014 - May 1, 2018

Developed business applications using JavaScript, web technologies, and relational databases with a focus on maintainable full-stack delivery. Implemented interactive, reusable UI components and responsive patterns for consistent behavior across screen sizes. Constructed backend endpoints with validation, error handling, authentication checks, and structured responses. Migrated legacy functionality into cleaner modules to reduce duplicated logic and improve boundaries. Optimized SQL queries and indexing to improve frequently used operations. Automated recurring development/deployment tasks via scripting and source control. Tested critical workflows across browser, API, and database layers to identify integration defects early. Documented technical decisions, API behaviors, database structures, and deployment procedures. Diagnosed complex failures by tracing requests across frontend, backend, and persistence layers and applying targeted fixes without unnecessary rewrites. Enhanced se