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I am Mateusz Sadowski, a Senior Software Engineer with over 10 years of experience building scalable, full-stack applications and automation platforms for enterprise financial services. I specialize in Flutter, Supabase, Stripe integration, and modern cloud-based architectures to deliver production-grade mobile and web solutions that streamline operations and enable multi-market growth. I am passionate about transforming traditional industries through transparent, efficient, and user-centric technology, mentoring team members, and delivering impact at scale. Throughout my career I have led cross-functional initiatives, designed robust backend services, and built intuitive interfaces that reduce manual effort and improve stakeholder outcomes. I thrive in collaborative environments that value quality, security, and continuous improvement, and I enjoy sharing knowledge to elevate the entire engineering organization.…I am Mateusz Sadowski, a Senior Software Engineer with over 10 years of experience building scalable, full-stack applications and automation platforms for enterprise financial services. I specialize in Flutter, Supabase, Stripe integration, and modern cloud-based architectures to deliver production-grade mobile and web solutions that streamline operations and enable multi-market growth. I am passionate about transforming traditional industries through transparent, efficient, and user-centric technology, mentoring team members, and delivering impact at scale. Throughout my career I have led cross-functional initiatives, designed robust backend services, and built intuitive interfaces that reduce manual effort and improve stakeholder outcomes. I thrive in collaborative environments that value quality, security, and continuous improvement, and I enjoy sharing knowledge to elevate the entire engineering organization.

Mateusz Sadowski

Full Stack Developer, Web Developer, Back-End Developer, +4

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I am Mateusz Sadowski, a Senior Software Engineer with over 10 years of experience building scalable, full-stack applications and automation platforms for enterprise financial services. I specialize in Flutter, Supabase, Stripe integration, and modern cloud-based architectures to deliver production-grade mobile and web solutions that streamline operations and enable multi-market growth. I am passionate about transforming traditional industries through transparent, efficient, and user-centric technology, mentoring team members, and delivering impact at scale. Throughout my career I have led cross-functional initiatives, designed robust backend services, and built intuitive interfaces that reduce manual effort and improve stakeholder outcomes. I thrive in collaborative environments that value quality, security, and continuous improvement, and I enjoy sharing knowledge to elevate the entire engineering organization.…I am Mateusz Sadowski, a Senior Software Engineer with over 10 years of experience building scalable, full-stack applications and automation platforms for enterprise financial services. I specialize in Flutter, Supabase, Stripe integration, and modern cloud-based architectures to deliver production-grade mobile and web solutions that streamline operations and enable multi-market growth. I am passionate about transforming traditional industries through transparent, efficient, and user-centric technology, mentoring team members, and delivering impact at scale. Throughout my career I have led cross-functional initiatives, designed robust backend services, and built intuitive interfaces that reduce manual effort and improve stakeholder outcomes. I thrive in collaborative environments that value quality, security, and continuous improvement, and I enjoy sharing knowledge to elevate the entire engineering organization.

Available to hire

I am Mateusz Sadowski, a Senior Software Engineer with over 10 years of experience building scalable, full-stack applications and automation platforms for enterprise financial services. I specialize in Flutter, Supabase, Stripe integration, and modern cloud-based architectures to deliver production-grade mobile and web solutions that streamline operations and enable multi-market growth. I am passionate about transforming traditional industries through transparent, efficient, and user-centric technology, mentoring team members, and delivering impact at scale.

Throughout my career I have led cross-functional initiatives, designed robust backend services, and built intuitive interfaces that reduce manual effort and improve stakeholder outcomes. I thrive in collaborative environments that value quality, security, and continuous improvement, and I enjoy sharing knowledge to elevate the entire engineering organization.

Skills

Experience Level

Expert

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Language

Polish

Fluent

English

Advanced

Work Experience

Forward Deployed Software Engineer at Palantir Technologies

July 1, 2022 - June 1, 2026

Architected and deployed full-stack enterprise solutions using Flutter for mobile and React for web dashboards, serving over 1,200 daily users across financial institutions including the Bank of England. Built backend services with Supabase and PostgreSQL, implementing real-time data synchronization that reduced latency from 450ms to 85ms and improved cross-platform UX. Integrated Stripe for payments and subscription management, processing over 50,000 transactions monthly and lowering payment failures from 6.5% to 1.2%. Created automation workflows with Python and FastAPI to streamline document processing and reporting, reducing manual work from 8 hours to 22 minutes per week. Designed scalable marketplace-style matching algorithms that improved match accuracy by 40% and reduced response times from 3 minutes to 18 seconds. Led multi-platform UX consistency, achieving high user satisfaction and lowering support tickets. Integrated AWS S3 and Twilio, and mentored 4 junior engineers on Fl

Senior Software Engineer at Vodeno

February 1, 2019 - May 1, 2022

Developed full-stack banking applications with React frontend and Java Spring Boot microservices, supporting real-time payments for over 2 million active users across European markets. Implemented RESTful APIs with OAuth 2.0 and JWT authentication, integrating with third‑party payment gateways and reducing API latency from 280ms to 85ms. Built automation workflows for transaction monitoring and fraud detection, reducing manual review time from 45 minutes to 7 minutes per flagged transaction. Engineered event-driven architectures with Apache Kafka and RabbitMQ, processing over 50,000 transactions per second with 99.99% reliability. Created responsive web interfaces using React/TypeScript with Redux, achieving Lighthouse scores around 92 and boosting user engagement by 35%. Implemented automated CI/CD pipelines using GitHub Actions and Docker, reducing deployment time from 4 hours to 12 minutes. Optimized PostgreSQL performance with indexing and query refactoring across 200+ tables.

Full Stack Java Developer at HRS Group

May 1, 2018 - January 1, 2019

Developed enterprise hotel booking platform using Java Spring Boot microservices and PostgreSQL, processing 10,000 daily bookings across 50,000 global properties. Built RESTful APIs with OpenAPI/Swagger, integrating with external payment gateways and reducing API latency from 210ms to 75ms. Implemented Redis caching for frequently accessed inventory data, reducing database load by 45% and improving page load times from 1.8s to 0.6s. Created automated testing frameworks using JUnit and Mockito, reducing regression testing cycles via Jenkins. Optimized PostgreSQL query performance with advanced indexing and query rewriting, achieving 55% improvement in complex joins across 15 million records. Collaborated with cross-functional teams in Agile sprints to deliver features aligned with the product roadmap.

Java Developer at Decerto sp. z o.o.

September 1, 2015 - May 1, 2018

Designed and developed enterprise web applications for insurance clients using Java EE and Oracle databases, serving 500,000 policyholders across multiple European countries. Built RESTful web services with Jersey framework and integrated with external claims systems, reducing data exchange latency from 450ms to 120ms. Implemented complex business logic modules for policy management and claims processing using JPA and EJB, reducing manual processing time from 45 minutes to 7 minutes per claim. Created batch processing solutions using Quartz Scheduler for nightly data synchronization, eliminating manual reconciliation errors and saving 6 hours of weekly maintenance. Performed code reviews, mentoring 3 junior developers and producing technical documentation and SQL optimization guides to improve team productivity.