Krzysztof Kwiecień, Developer in Warsaw, Poland
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Krzysztof Kwiecień

Verified Expert  in Engineering

Software Development Developer

Warsaw, Poland
Toptal Member Since
December 2, 2020

Krzysztof has three years of experience in Deloitte Digital as a full-stack developer, currently in a management position. During his tenure, he worked for various clients from the banking, insurance, pharmaceutical, retail industries, and public sectors. Before that, he spent two years in Accenture as both web developer and team leader, where he worked on projects regarding insurance and financial services.


Engineering Management, React, Amazon Web Services (AWS), Docker, TypeScript...
Engineering Management, Delivery Management, React, Amazon Web Services (AWS)...
Deloitte Digital
SCSS, Azure, Salesforce, Software Evaluation, Recruiting, CSS, HTML, Express.js...




Preferred Environment

Git, MacOS, Visual Studio Code (VS Code)

The most amazing...

...project I've worked on is introducing the client's IT team to scrum development, Angular, and Node.js, and developing an app from scratch in three months.

Work Experience

Engineering Manager

2022 - PRESENT
  • Managed engineering delivery in a group of three teams. Led and mentored 11 engineers, including one engineering manager.
  • Led sign-in development with Klarna, Klarna Express button, and Express Checkout in all Klarna markets.
  • Released the SSO product for merchants in Sweden, getting 15% of all sign-ups overnight.
  • Led self-onboarding delivery for two products, focusing on the user journey for merchants and consumers, minimizing effort for the PST team.
  • Slashed IT spending by 30% through savvy budgeting. Optimized operations, eliminated redundant services, halved costs, and streamlined maintenance efforts.
  • Contributed to promoting three engineers to senior roles and one to a lead position.
  • Led cross-domain initiatives and contributed to unifying Klarna's APIs and credentials, wrote and reviewed API change documents, prepared implementation plan,s and executed parts of them.
Technologies: Engineering Management, React, Amazon Web Services (AWS), Docker, TypeScript, Node.js, Jenkins, Software Architecture, System Design, Front-end, Back-end

Engineering Manager

2021 - 2022
  • Crafted a visionary 3-year strategy for the front-end/Salesforce developers team, aligning technical initiatives with business goals.
  • Nurtured a team of seven software engineers, implementing personalized growth plans that resulted in two engineers advancing to the next level.
  • Established and cultivated a thriving partnership with one of the largest clients from the US, leading to an impressive extension of our initial engagement by an additional year, with an increased team size to support the collaboration.
  • Introduced a successful mentoring program, enhancing junior developers' skills and fostering a culture of continuous learning.
Technologies: Engineering Management, Delivery Management, React, Amazon Web Services (AWS), TypeScript, Node.js, PostgreSQL, Angular, GraphQL, Front-end, Back-end

Full-stack Developer

2018 - 2021
Deloitte Digital
  • Developed a React-web application integrated with SharePoint. Helped design and implement a dashboard, presenting detailed information regarding each funding application.
  • Implemented HTML and CSS3 for desktop, tablet, and mobile with Qlik-data integration. Built an interactive tool capable of achieving the overreaching goal of aid transparency.
  • Helped with the full-stack development for medical affairs and vaccines departments. Worked with Angular 7 and Node.js connected with the MySQL database.
  • Developed an Angular app hosted on Azure, used to facilitate calculating the needed amount and type of tools for a particular drilling project.
  • Designed a front-end architecture for a React web app, Next.js email template builder, and a platform to utilize these templates for one of the FAANG companies. Led a team of eight front-end developers on these two streams.
Technologies: SCSS, Azure, Salesforce, Software Evaluation, Recruiting, CSS, HTML, Express.js, TypeScript, Redux, RxJS, Microsoft SQL Server, Node.js, React, Angular, JavaScript

Rollout Consultant

2016 - 2018
BSH Hausgeräte
  • Contributed to the implementation of IT solutions in the fields of WCMS, eCommerce, and customer service.
  • Provided business and technical support to corporate and regional customers.
  • Maintained the problem documentation and managed the knowledge library.
  • Carried out on-site technical training for 30 people from many different countries.
Technologies: Confluence, Jira, CSS, HTML, JavaScript 6, React, eCommerce, Testing, E2E Testing, Project Management

Web Developer

2014 - 2016
  • Developed the front end of a crucial part of the CRM 360 dashboard view for users.
  • Improved the client's existing front-end JavaScript framework.
  • Developed a platform that connects insurance companies, garages, and vehicle owners. The app suggested cheaper replacement parts for users.
Technologies: Frameworks, PostgreSQL, AngularJS, Spring Boot, Jakarta Server Pages (JSP), CSS, HTML, JavaScript

Dashboard for Investment Banking Clients

An app made for a German investment bank. It shows the current state of an application that the users raised. I created only the front-end part since SharePoint was used as a back end.

React with Redux and TypeScript were used to speed up the development and create a library of reusable components that the client might use to extend the app.

First Point of Contact App for a Manufacturing Sector Client

The aim of developing this app was to digitize one step in the process of buying tools. Interactive and animated forms were used to make it more user-friendly and appealing. I created the app from scratch, including its front end, back end, and data layer.

Intranet for a Consulting Company

Developed an app that integrates data from many different systems that the clients can use and show appealingly. It also enables users to change the data while respecting all the client's business rules and policies.

Website for a Medical Clinic in Poland

Built a new website for a medical clinic based in Warsaw, Poland, called Przychodnia i Endoterapia Polskiej Fundacji Gastroenterologii.

The website includes pages for all the clinic's services, doctors who work there, and other various data essential to the patients. The traffic has increased by 15% since the new website was introduced.
2013 - 2017

Bachelor's Degree in Computer Science

Warsaw University of Technology - Warsaw, Poland

APRIL 2022 - APRIL 2025

AWS Certified Cloud Practitioner

Amazon Web Services


Agile Project Management Foundation

APMG International


React, Node.js, RxJS


Git, Jira, Confluence, Webpack, Jenkins


AngularJS, Angular, Jakarta Server Pages (JSP), Spring Boot, Redux, Express.js


JavaScript, HTML, CSS, TypeScript, SCSS, JavaScript 6, GraphQL

Industry Expertise

Project Management


Agile Project Management, E2E Testing, Testing


Amazon Web Services (AWS), MacOS, Salesforce, Azure, Visual Studio Code (VS Code), Docker


PostgreSQL, Microsoft SQL Server


Software Development, Front-end, Software Design, Software Architecture, eCommerce, Recruiting, Engineering Management, Back-end, Software Evaluation, Gatsby, Frameworks, Delivery Management, System Design

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