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I am a software engineer with 9 years of experience delivering full-stack applications, backend services, and cloud-based platforms across EU and UK teams. Based in Poland, I collaborate remotely with cross-functional groups to ship reliable software and drive business outcomes. I leverage JavaScript, TypeScript, and Java, along with React, Node.js, and cloud-native patterns to build scalable solutions that users love. In my work, I translate product requirements into robust architectures, improve system reliability and performance, and empower teams with observable, secure APIs and end-to-end workflows. I enjoy turning complex problems into practical, maintainable solutions and continuously refining processes for faster, safer releases.…I am a software engineer with 9 years of experience delivering full-stack applications, backend services, and cloud-based platforms across EU and UK teams. Based in Poland, I collaborate remotely with cross-functional groups to ship reliable software and drive business outcomes. I leverage JavaScript, TypeScript, and Java, along with React, Node.js, and cloud-native patterns to build scalable solutions that users love. In my work, I translate product requirements into robust architectures, improve system reliability and performance, and empower teams with observable, secure APIs and end-to-end workflows. I enjoy turning complex problems into practical, maintainable solutions and continuously refining processes for faster, safer releases.

John William Lim

Full Stack Developer, Back-End Developer, Front-End Developer, +3

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I am a software engineer with 9 years of experience delivering full-stack applications, backend services, and cloud-based platforms across EU and UK teams. Based in Poland, I collaborate remotely with cross-functional groups to ship reliable software and drive business outcomes. I leverage JavaScript, TypeScript, and Java, along with React, Node.js, and cloud-native patterns to build scalable solutions that users love. In my work, I translate product requirements into robust architectures, improve system reliability and performance, and empower teams with observable, secure APIs and end-to-end workflows. I enjoy turning complex problems into practical, maintainable solutions and continuously refining processes for faster, safer releases.…I am a software engineer with 9 years of experience delivering full-stack applications, backend services, and cloud-based platforms across EU and UK teams. Based in Poland, I collaborate remotely with cross-functional groups to ship reliable software and drive business outcomes. I leverage JavaScript, TypeScript, and Java, along with React, Node.js, and cloud-native patterns to build scalable solutions that users love. In my work, I translate product requirements into robust architectures, improve system reliability and performance, and empower teams with observable, secure APIs and end-to-end workflows. I enjoy turning complex problems into practical, maintainable solutions and continuously refining processes for faster, safer releases.

Available to hire

I am a software engineer with 9 years of experience delivering full-stack applications, backend services, and cloud-based platforms across EU and UK teams. Based in Poland, I collaborate remotely with cross-functional groups to ship reliable software and drive business outcomes. I leverage JavaScript, TypeScript, and Java, along with React, Node.js, and cloud-native patterns to build scalable solutions that users love.

In my work, I translate product requirements into robust architectures, improve system reliability and performance, and empower teams with observable, secure APIs and end-to-end workflows. I enjoy turning complex problems into practical, maintainable solutions and continuously refining processes for faster, safer releases.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Intermediate

Intermediate

Intermediate

Intermediate

Language

English

Fluent

Work Experience

Senior Software Engineer at Slalom

March 1, 2023 - Present

Optimized mobile-facing fintech application flows by refining UI behavior, improving screen consistency, and resolving edge-case issues affecting transaction and wallet-related experiences. Debugged and stabilized API integrations across distributed services, reducing user-facing data mismatches and improving reliability in fintech workflows. Improved onboarding and navigation journeys for customer-facing fintech products by simplifying state handling, validation logic, and transition behavior across key entry points. Increased debugging efficiency through stronger logging, traceability, and diagnostic workflows for production issues impacting app stability. Reduced duplicate transaction-related issues by implementing idempotent request handling and consistent client-server interaction patterns. Improved data access performance by up to 40% through API and backend optimizations, enabling faster rendering for transaction-heavy fintech views. Partnered with product and engineering teams

Full Stack Developer at Kitrum

July 1, 2021 - February 28, 2023

Built and optimized mobile and web application features for fintech, ecommerce, and SaaS products using Flutter, React, Angular, Vue, and TypeScript. Refined reusable UI components and design patterns to improve cross-screen consistency, reducing frontend rew ork and accelerating feature delivery for fintech and SaaS interfaces. Reduced page load time by 25% through rendering optimization, lazy loading, and more efficient state management across user-facing apps. Improved API response time by ~15% via caching strategies, request optimization, and tighter frontend-backend coordination in fintech and commerce flows. Streamlined onboarding and checkout journeys by simplifying form interactions, validation states, and navigation behavior. Debugged third-party integrations including Stripe, PayPal, and Shopify, strengthening data flow reliability and reducing support issues during high-volume periods. Increased system throughput by ~20% during peak traffic by optimizing async workflows, UI

Backend Developer at NCS

September 1, 2019 - December 31, 2020

Built backend services supporting document workflows, OCR processing, and data extraction systems for enterprise software environments. Developed asynchronous pipelines using Kafka and Redis to improve throughput and reliability. Implemented search and retrieval services using Elasticsearch to support faster access to operational records. Supported integration reliability and service observability for workflow-driven applications used in regulated business contexts.

Software Engineer at Shopee

December 1, 2017 - December 31, 2019

Supported frontend enhancements, backend APIs, and debugging tasks for high-traffic e-commerce platforms. Improved UI responsiveness and contributed to feature delivery across user-facing product teams. Assisted with testing, integration work, and issue resolution to maintain release quality in fast-moving application environments.

Junior Software Developer at Shopee

December 1, 2017 - September 30, 2019

Built backend services and internal APIs for AI-powered features and automation tools supporting operational workflows at scale. Improved pre-processing, validation, and error-handling logic to reduce avoidable failures in production data pipelines.