Grzegorz is available for hire
Hire GrzegorzGrzegorz Pawlik
Verified Expert in Engineering
Front-end Developer
Porto, Portugal
Toptal member since March 24, 2022
Bio
Grzegorz is a software engineer with over ten years of experience in companies ranging from startups to multinational enterprises. He focuses on React, React Native, Node.js, and JavaScript. As an open-minded professional with technical and problem-solving skills that add value to every project, Grzegorz enjoys writing clean code and collaborating with a team to encourage innovation and empower them to take ownership of the product.
Portfolio
The Economist
React, React Native, TypeScript, GitHub, Amazon Web Services (AWS), iOS...
Gocompare.com
React, React Native, TypeScript, Node.js, Azure, GitHub, Back-end, REST APIs...
British Gas
React, React Native, JavaScript, Flow, GitHub, Amazon Web Services (AWS)...
Experience
- JavaScript - 9 years
- React - 6 years
- TypeScript - 6 years
- Redux - 6 years
- React Native - 5 years
- PHP - 4 years
- Node.js - 4 years
- GraphQL - 3 years
Preferred Environment
MacOS, Slack, Jira, ClickUp
The most amazing...
...thing I've worked on is the new React Native version of the Hive app, one of the highest-rated smart home apps in the UK with over 70,000 customer reviews.
Work Experience
Senior React Native Developer
2021 - PRESENT
The Economist
- Completed migration of the main The Economist app to React Native, replicating all the screens and functionalities from the existing native apps.
- Implemented best practices and optimization techniques to improve the app's performance and reliability, as it was reaching an audience of about 10+ million users.
- Developed the audio-related features, including article playback and audio download. It involved working on the native side with Swift and Java to accommodate all the missing audio functions and fix the issues and edge cases.
Technologies: React, React Native, TypeScript, GitHub, Amazon Web Services (AWS), iOS, REST APIs, Application State Management, React Native for Web, Expo, EAS, TestFlight, SQLite, Tailwind CSS, i18next, Android, Mobile Design, Mobile UI Design, UI Animation, UI Design, UI Engineering, User Interface (UI), Web Design, Artificial Intelligence (AI), Mathematical Modeling, SaaS, Stripe API, Stripe Connect, Blockchain, Cryptocurrency, Fintech, AI Agents, Google Maps API, Flutter, React Components, Software Architecture, Third-party APIs, Data Pipelines, AI-assisted Development
Senior React Native Developer
2020 - 2021
Gocompare.com
- Created integrations with several core company products, allowing users to find the cheapest car insurance and manage their insurance policies.
- Developed a car diagnostics mobile app that relies on the OBD device connected to the users' vehicle. The app notifies the user about any potential issues with their car, includes the history of recent journeys, and provides driving habits breakdown.
- Implemented the Node.js back-end API that covered push notifications management and relied on the Azure infrastructure (Azure DevOps, AD B2C, and Cosmos DB).
Technologies: React, React Native, TypeScript, Node.js, Azure, GitHub, Back-end, REST APIs, Application State Management, React Native for Web, Expo, EAS, TestFlight, SQLite, Tailwind CSS, Firebase, GraphQL, Mobile Design, UI Animation, UI Design, UI Engineering, User Interface (UI), Web Design, AI Integration, Full-stack, Software as a Service (SaaS), Twilio, Claude Code, Dashboards, Gemini API, React Components, Architecture, Data Pipelines, AI-assisted Development
Senior React Native Developer
2017 - 2020
British Gas
- Contributed to a large-scale project for British Gas, the UK's leading energy and smart home services company. The biggest challenge was the migration of the native mobile apps to React Native, which was effectively completed.
- Created a set of performance solutions that allowed the new app to outperform the native app in terms of speed and quality.
- Developed the architecture for the automated tests.
Technologies: React, React Native, JavaScript, Flow, GitHub, Amazon Web Services (AWS), REST APIs, Application State Management, Responsive Web Apps, Expo, EAS, TestFlight, APIs, GraphQL, Minimum Viable Product (MVP), Blockchain, Cryptocurrency, Fintech, Mobile App Development, Prisma, Dashboards, Vibe Coding, React Components, Architecture, Role-based Access Control (RBAC), Software Architecture, Software Design, Agentic Coding, Prompt Engineering, Cursor AI
Senior JavaScript Developer
2017 - 2017
NearForm
- Implemented data migration platform using Node.js and Hapi.js for several renowned online magazines, such as Vogue, Glamour, GQ, and Vanity Fair.
- Created a set of scripts that allowed the content creators to improve the quality of the articles.
- Developed several UI features on the new front-end app.
Technologies: JavaScript, Node.js, GitHub, Back-end, REST APIs, Responsive Web Apps, Next.js, NestJS, APIs, Firebase, PostgreSQL, REST, Java, Apache Kafka, API Integration, Full-stack, Stripe, Prisma, IT Security, Vite, AWS Cloud Architecture, LangGraph, Docker, Elixir, Role-based Access Control (RBAC), Software Design, Third-party APIs, Data Engineering
Senior JavaScript Developer
2016 - 2017
CornerJob
- Improved the microservices architecture using Node.js, MongoDB, and Elasticsearch, which powered the React web app and native mobile apps, achieving the goal of 99.9% production uptime.
- Implemented numerous features on the client side to increase the number of subscribers.
- Carried out the web app's performance improvements (SSR, code splitting, and offline caching) that reduced time to interactive by over 40% and achieved load time under 2.5 seconds over 3G.
Technologies: JavaScript, React, Node.js, Redux, Full-stack Development, Large Language Models (LLMs), Supabase, Python, Amazon MSK, DevOps, Stripe Subscriptions, Vercel, Twilio, IT Security, Google Cloud Platform (GCP), SendGrid, Redis, Technical Leadership, Agentic Coding
JavaScript Developer
2012 - 2016
eDreams ODIGEO
- Created a new front-end web app with JavaScript and Backbone.js used by 2+ million customers daily in more than 40 markets.
- Optimized a functional test architecture that helped increase coverage from less than 20% to over 90% using Selenium and Cucumber, significantly improving code reliability and decreasing the number of bugs.
- Won the internal Hackathon together with two workmates with an MVP project that was added to the company product portfolio a few months later.
- Supported the marketing and data science department by creating front-end solutions with JavaScript and React, helping to analyze and easily manage SEM campaigns.
- Used Java, Python, and MySQL to develop multiple scripts on the back-end side to automate the creation of AdWords campaigns with a total yearly budget exceeding €1 million, which provided a significant cost optimization to the company.
- Created and maintained a CMS platform with JavaScript, PHP, MySQL that was used to generate and run over 250 marketing contests, helping to increase the user base from 10,000 to 350,000 in less than two years.
- Oversaw the development of the new blogging multi-site system with WordPress and Drupal running on six markets and achieved a 150% increase in user daily visits compared to the previous solution.
Technologies: JavaScript, PHP, React, Laravel, Backbone.js, GraphQL, Redux, Terraform
Experience
The Economist
The Economist is an award-winning, trusted filter on global affairs, offering in-depth analysis of everything from business, finance, and politics to science, technology, and economics.
I contributed to migrating the native apps to the React Native app, including delivering a complete redesign and new features related to the audio and podcast content.
The app provides:
• the latest news analysis and highlights from the weekly issue,
• short morning briefing on the day’s global news,
• full access to the weekly version of The Economist newspaper,
• the audio version of the weekly edition to listen while on the go,
• selection of podcasts,
• reading times that are highlighted on each article, and
• bookmarks to save articles for later or create personal reading lists.
I contributed to migrating the native apps to the React Native app, including delivering a complete redesign and new features related to the audio and podcast content.
The app provides:
• the latest news analysis and highlights from the weekly issue,
• short morning briefing on the day’s global news,
• full access to the weekly version of The Economist newspaper,
• the audio version of the weekly edition to listen while on the go,
• selection of podcasts,
• reading times that are highlighted on each article, and
• bookmarks to save articles for later or create personal reading lists.
Hive App
https://www.hivehome.com/Hive is the UK's leading provider of smart-home technology and aims to deliver a seamless smart home experience for everyone. Their intelligent products work in conjunction with one another to control the home's heating, security, lighting, sockets, and even potential water pipe leaks.
With over 1,000,000 users in the UK, Hive helps automate the home to free up time for other things in life. Their products are fully compatible with Apple HomeKit, Amazon Alexa, and Google Assistant.
I worked on the new React Native version of the Hive app, one of the highest-rated smart home apps in the UK with four stars* from over 70,000+ customer reviews.
With over 1,000,000 users in the UK, Hive helps automate the home to free up time for other things in life. Their products are fully compatible with Apple HomeKit, Amazon Alexa, and Google Assistant.
I worked on the new React Native version of the Hive app, one of the highest-rated smart home apps in the UK with four stars* from over 70,000+ customer reviews.
Scalable Job Marketplace Web Platform
I worked as a Senior JavaScript Developer on a high-traffic job marketplace platform built with React, Node.js, MongoDB, and Elasticsearch. My main focus was improving the microservices architecture powering both the React web app and the native mobile applications. I helped strengthen back-end reliability, optimize search and data retrieval, and support production stability with a target of 99.9% uptime. On the front end, I implemented subscriber-focused features and improved performance through server-side rendering, code splitting, and offline caching. These optimizations reduced time to interactive by more than 40% and helped achieve load times under 2.5 seconds on 3G connections.
Education
2004 - 2010
Master's Degree in Computer Science
Wroclaw University of Technology - Wroclaw, Poland
Skills
Libraries/APIs
React, Node.js, REST APIs, React Native for Web, Stripe, Stripe API, Google Maps API, Stripe Connect, Backbone.js
Tools
GitHub, Expo, TestFlight, Prisma, Claude Code, SendGrid, Terraform, Flow, Slack, Jira
Languages
TypeScript, JavaScript, GraphQL, HTML, CSS, Python, Java, PHP, Elixir
Frameworks
React Native, Redux, Next.js, Tailwind CSS, i18next, NestJS, Flutter, Laravel, LangGraph
Paradigms
Microservices, Mobile Design, Mobile UI Design, UI Design, REST, DevOps, Role-based Access Control (RBAC)
Platforms
Amazon Web Services (AWS), Firebase, Apache Kafka, Vercel, Blockchain, Twilio, iOS, Android, Docker, Google Cloud Platform (GCP), Azure, MacOS
Storage
MongoDB, PostgreSQL, Data Pipelines, SQLite, Redis
Industry Expertise
Web Design
Other
Back-end, Application State Management, Responsive Web Apps, APIs, EAS, UI Animation, UI Engineering, User Interface (UI), Artificial Intelligence (AI), Full-stack Development, Large Language Models (LLMs), Supabase, AI Integration, Mathematical Modeling, Amazon MSK, API Integration, Full-stack, Minimum Viable Product (MVP), SaaS, Software as a Service (SaaS), Stripe Subscriptions, Cryptocurrency, Fintech, Mobile App Development, IT Security, Dashboards, React Components, Architecture, Technical Leadership, Software Architecture, Software Design, Third-party APIs, AI-assisted Development, Agentic Coding, Data Engineering, Prompt Engineering, Cursor AI, AI Agents, Gemini API, Vibe Coding, Vite, AWS Cloud Architecture, ClickUp, Offline Caching
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