Krzysztof Czernek, Developer in Kraków, Poland
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Krzysztof Czernek

Verified Expert  in Engineering

Full-stack Developer

Location
Kraków, Poland
Toptal Member Since
February 19, 2019

Krzysztof is a product-minded, full-stack developer with several years of experience, collaborating directly with startup founders and CEOs to bring their ideas to life and work on projects for Fortune 500 companies. He is passionate about lean product development and consulting. Thanks to his technical expertise, business focus, and ability to communicate in a clear and reasoned fashion, Krzysztof is a great partner for brainstorming ideas and delivering incredible products.

Portfolio

Deliveroo
JavaScript, TypeScript, React, Ruby, Ruby on Rails (RoR), Go, Terraform...
Pfizer
TypeScript, JavaScript, React, Node.js, PostgreSQL, Git, Docker, CSS...
Iterate Labs (via Toptal)
JetBrains, MacOS, REST, Lean Startups, Business Requirements, Team Leadership...

Experience

Availability

Part-time

Preferred Environment

Amazon Web Services (AWS), Slack, Google Chrome, JetBrains, GitHub, Git, Bash, MacOS, Agile

The most amazing...

...algorithm I've created analyzed meteorological phenomena areas and their impact on flight routes.

Work Experience

Senior Software Engineer

2021 - PRESENT
Deliveroo
  • Worked as a full-stack developer in a platform engineering team.
  • Maintained and improved an internal release management application used by hundreds of engineers daily. Helped rewrite the front end of the application, introducing a new design and refactoring a big part of the codebase.
  • Contributed to various elements of the development tooling ecosystem across the organization.
Technologies: JavaScript, TypeScript, React, Ruby, Ruby on Rails (RoR), Go, Terraform, Amazon Web Services (AWS), PostgreSQL, Docker, CircleCI, Git, CSS, GraphQL, Architecture, Front-end, Back-end

Tech Lead | Full Stack Developer

2020 - 2021
Pfizer
  • Led a distributed front-end development team of three people to create, from the ground up, a modern collaborative platform to replace the Excel-based processes of an internal team.
  • Contributed to the back-end development, database design, cloud architecture, and deployment processes and practices for the whole project.
  • Delivered the first MVP, from design specs to regular production deployments, in under three months.
  • Collaborated with business owners, designers, and technical stakeholders in defining requirements and designs.
Technologies: TypeScript, JavaScript, React, Node.js, PostgreSQL, Git, Docker, CSS, Architecture, Leadership, Front-end, Back-end, Next.js

Lead Software Engineer

2020 - 2020
Iterate Labs (via Toptal)
  • Maintained, improved, and scaled an AWS-based infrastructure for a real-time IoT data processing system of 1000s of events per second.
  • Designed and conducted end-to-end tests of the full data pipeline prior to production release.
  • Implemented and deployed admin applications for end users and back office administration of the system.
  • Implemented monitoring, alerting, data retention policies, and performance improvements across critical systems.
  • Collaborated with the in-house data science team on integrating data processing models into the system.
Technologies: JetBrains, MacOS, REST, Lean Startups, Business Requirements, Team Leadership, System Architecture, IT Consulting, ECMAScript (ES6), Consulting, Lean Product Development, Technical Leadership, APIs, GitHub, Algorithms, Amazon Kinesis, AWS Lambda, Ruby on Rails 5, Amazon S3 (AWS S3), Amazon EC2, Ruby, Bash, Software Consulting, Agile Software Development, Agile, Git, Amazon Web Services (AWS), Full-stack, Kubernetes, Docker, PostgreSQL, SQL, JavaScript, React, Ruby on Rails (RoR), CSS, Architecture, Leadership, Front-end, Back-end

Tech Lead | Full-stack Developer | Consultant

2013 - 2020
u2i
  • Maintained a mobile app, developed a data processing pipeline and helped with data migration from on-premise to the cloud in a healthcare institution.
  • Created a service for correlating data from disparate sources with a reference database of hundreds of millions of records.
  • Worked directly with a founder to take the idea from conception to a working prototype.
  • Created a collaborative platform for municipal governments from the ground up while working directly with a startup's CEO.
  • Helped multiple clients refine their ideas and develop plans for prototypes and MVPs.
  • Advised clients on technology, product development, and lean practices.
  • Helped find new clients, took an active part in early sales interactions, and contributed to writing proposals.
  • Ran workshops on JavaScript, functional programming, and organized hackathons.
  • Helped design and implement the recruitment process for junior, mid, and senior developers and conducted interviews.
  • Helped streamline the transition to remote work, developed internal tools, and improved internal processes.
Technologies: JetBrains, HIPAA Compliance, Functional Programming, MacOS, REST, Business Consulting, Semantic UI, Lean Startups, Business Requirements, Team Leadership, System Architecture, IT Consulting, ECMAScript (ES6), Consulting, Lean Product Development, Technical Leadership, APIs, GitHub, Algorithms, React Native, PostgreSQL, AWS Lambda, RxJS, TypeScript, Amazon S3 (AWS S3), Amazon EC2, MySQL, Bash, Software Consulting, Express.js, Redux, Agile Software Development, Agile, Amazon Web Services (AWS), Full-stack, Git, Terraform, Docker, SQL, Flask, Ruby on Rails (RoR), Node.js, React, Python, Ruby, JavaScript, CSS, Architecture, Leadership, Front-end, Back-end, Next.js

Software Engineer Intern

2013 - 2013
Smart4Aviation
  • Worked on algorithmic solutions to area related problems.
  • Analyzed meteorological phenomena and their impact on flight routes.
  • Mentioned in an errata for finding a mathematical mistake in "Some Algorithms for Polygons on a Sphere" by Robert G. Chamberlain and William H. Duquette (NASA Jet Propulsion Laboratory).
Technologies: Algorithms, Java, Back-end

Software Engineer

2013 - 2013
Schibsted Tech Polska
  • Built an iPhone application for sports statistics from the ground up, in two months, with no prior experience with iOS and Objective-C.
Technologies: JetBrains, MacOS, APIs, GitHub, Bash, Agile Software Development, Agile, Git, SQL, Full-stack, Java, Objective-C, Back-end

Release Management Application

Internal release management application used by hundreds of engineers daily.

I handled the full-stack development, executed a major web application redesign, and introduced improvements to the release management process across the organization.

Technologies: JavaScript, TypeScript, React, Ruby on Rails, Docker, AWS, Terraform, Go, CircleCI

Data Processing Pipeline and Mobile App | Healthcare

I handled the full-stack development of a data processing pipeline and maintenance of a cross-platform mobile app in the healthcare space along with the migration from on-premise to a cloud-based infrastructure.

I took an active part in all stages of the project: from proposals and defining requirements to technical strategy planning and hands-on full-stack development. I also worked in a team of four developers for over a year.

• Client's review: https://clutch.co/profile/u2i#review-1392252

Technologies: Python, JavaScript, Flask, Apache Airflow, React Native, React, Docker, Terraform, AWS

Data-matching Service

A service for correlating data from disparate sources with a reference database of hundreds of millions of records, heavily utilizing string similarity algorithms. This is a mission-critical system that's been running in production for over two years now with minimal maintenance and support required.

I handled the full-stack development and architecture design from the ground up. I worked in a team of two developers for nine months.

Technologies: Ruby, Ruby on Rails, MySQL, Terraform, Chef, Capistrano

Citymart Opportunity Builder

A collaborative platform for municipal governments to streamline and improve procurement processes.

I handled the full-stack development and architecture design from the ground up and for two years, I worked in a team of 2-4 developers.

• Review: https://clutch.co/profile/u2i#review-409571

Technologies: JavaScript, React, Redux, RxJS, Webpack, Jest, Node.js, Python, Flask, PostgreSQL, Docker, Terraform, AWS

Personal Knowledge Management System

A prototype for a personal knowledge management system to help business people better manage their information.

I handled the full-stack development and architecture design from the ground up. I worked in a team of two developers for six months.

Review: https://clutch.co/profile/u2i#review-764612

Technologies: JavaScript, TypeScript, React, Redux, RxJS, Webpack, Jest, Node.js, Neo4j, Docker

Articles on Functional Programming in JavaScript

A series of articles on functional programming in JavaScript. It was published in DailyJS on Medium.

Articles on Consulting and Lean for Software Developers

https://hackernoon.com/@krzysztof.czernek
A series of articles on Consulting and Lean for Software Developers. It was published in Hacker Noon at Medium.

Languages

JavaScript, ECMAScript (ES6), SQL, TypeScript, Bash, Ruby, HTML, Objective-C, Java, Python, Go, CSS, GraphQL

Frameworks

Redux, Express.js, Material UI, Jest, Ruby on Rails 5, Ruby on Rails (RoR), React Native, Next.js, Flask

Libraries/APIs

Node.js, React, RxJS

Tools

GitHub, Git, Terraform, CircleCI, JetBrains

Paradigms

Agile, Agile Software Development, REST, Functional Programming, HIPAA Compliance

Platforms

Amazon Web Services (AWS), Docker, Amazon EC2, AWS Lambda, MacOS, Kubernetes, Firebase

Storage

Amazon S3 (AWS S3), PostgreSQL, MySQL

Other

Technical Leadership, Full-stack, APIs, Lean Product Development, Consulting, Architecture, Leadership, Front-end, Back-end, Software Consulting, Team Leadership, System Architecture, Business Requirements, Algorithms, Lean Startups, IT Consulting, Business Consulting, Semantic UI, SaaS, Amazon Kinesis

2011 - 2015

Bachelor of Engineering Degree in Computer Science

AGH University of Science and Technology - Kraków, Poland

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