Deniz Kalayci,
full stack developer

Personal Statement

As an exceptionally focused software developer with many years of experience in a variety of software technologies, I work at all times in an organised and systematic manner with a keen eye for detail. This enables me to deliver detailed solutions in solid coding, resulting in professional and reliable software. Clean Code is a part of my life philosophy. Some of my core strengths are understanding the customer and maintaining communication throughout the entire developmental process of a project, ensuring a continuous and mutually satisfying business relationship.


German (native), English (fluent), Turkish (fluent)


TypeScript & JavaScript

Core Capabilities

As a full stack developer, I offer a broad knowledge of object-orientated software development in both frontend and backend. This includes web servers, such as Apache; operating systems, such as Linux and MacOS; SQL databases; and industry-leading web technology such as PHP 7, JavaScript, CSS3 and HTML5 for the development of fully responsive and state-of-the-art websites.

My skill set includes extensive expertise in PHP (Symfony); JavaScript (React, Vanilla-JS, jQuery, Node, Webpack); CSS (Plain- CSS, Bootstrap); CSS Pre-Compiler (SCSS, LESS); database systems (PostgreSQL, MySQL); as well as development tools such as IntelliJ, Git, Docker and the Atlassian products for documentation, continuous integration, development boards (Kanban) and versioning (Confluence, Bitbucket, Bamboo, Jira). Due to my strong analytical competence as well as my inner composure, I invariably make the right decisions, even when under considerable pressure. Since I have been active as a web developer, I have worked in an agile team of software developers.


Project - Fintory

Berlin, March 2020 - current

Fintory is a digital web agency offering a broad range of services including the design and development of web and mobile apps. I was tasked with extending two existing single page applications written in TypeScript and React. Additionally, I had responsibility for two backends written in Ruby on Rails, both functioning as an API and serving a React web app or a React Native mobile app.

My main task involved building a frontend for one of their bigger clients. It was a trading platform where customers trade currency and cryptocurrency in real time. In order to build a sustainable frontend architecture, I decided to use the current version of React including React Hooks, TypeScript 4 and the current version of Redux Toolkit. Working in an agile team of designers and backend developers, I designed the architecture and built the frontend myself.


  • Architectural design and development of a React web app
  • Extending an existing React web app
  • Extending existing Ruby on Rails APIs
  • Extending an existing React Native mobile app
  • Bug analysis and bug fixing
  • Deployment to Google Cloud

Technologies used

  • React.JS
  • Redux Toolkit
  • TypeScript
  • Ruby on Rails
  • React Native


Berlin, September 2019 - December 2019

OZCULPTURAL, an architect and artist, came to me seeking an online shop that could be expanded easily in the future. Straight away I decided to use Sylius, a Symfony e-commerce framework, for the project as it provides the basic structure for a shop. Together we designed a minimalistic and responsive website, which I then implemented.

I am continuing to support OZCULPTURAL with all of his technical needs, digital business processes and software implementation. As a Symfony project, the website is very developer-friendly and new features can be added to it quickly and easily.


  • UI / UX design & implementation
  • Building a custom template from scratch for Sylius
  • Adjusting the website to the exact needs of the client

Technologies used

  • Sylius
  • Symfony
  • jQuery

Project - Legal one GmbH

Berlin, August 2019 - current

I returned to Legal One GmbH to take on new projects, as well as to extend the systems I put in place when I worked with them previously. My main task was a legacy project that needed to be rewritten and modernised. It allows clients to give their assigned lawyer a power of attorney and to agree to the terms & conditions as well as payment. I utilised Symfony 4 to get a quick result and release an MVP. With an A/B test, we compared the classic approach of using Symfony & Twig against using Symfony as an API with a React single page application as its frontend.

I was also asked to improve some of their internal systems by adding features with third party services such as SaaS. For these features, I have written automated test cases.


  • Building legacy software clone from scratch
  • Extension of various software projects
  • Bug-analysis and fixing bugs
  • Writing tests

Technologies used

  • React.JS
  • Symfony 4

Project - Klarna AB

Berlin, August 2018 - July 2019

I was tasked with rewriting Klarna’s technical documentation platform. When I analysed the platform to begin rewriting it, it was a GatsbyJS static website with markdown files as the content. I was required to recreate the same platform, but I utilised React-Static for a more lightweight building process and a better design system. Additionally, I added custom React components to be used in markdown. Thus, authors of the platform can mix and match markdown and React components according to their needs, resulting in a perfectly designed developer portal.

I also created a new frontend with React.JS and Redux.JS for a tool in Klarna’s ‘Merchant Portal’, a collection of web-based tools for businesses that have integrated Klarna into their online shops.


  • Developer portal from scratch
  • Frontend for logs app in Klarna’s ‘Merchant Portal’ from scratch
  • Supporting Developers’ Experience Team with bug fixing for all frontend matters

Technologies used

  • React.JS
  • Node.JS
  • Redux.JS
  • SCSS
  • webpack
  • React-Static
  • MDXC

Project - Legal one GmbH

Berlin, December 2017 - July 2018

I worked for Legal One GmbH on many varied projects, which mainly entailed analysing bugs and then fixing them. I used React.JS to develop a password generator widget, based on their former PHP password generator. The widget generates password options for the client and additionally features a password generator widget builder, where the user can change the appearance and colours of the widget and embed it on their own page. The password generator is completely safe as the code is executed on the client’s side, rather than on the server.

My main task involved rewriting a React.JS-based web project that is used to generate qualified leads. It is based on ‘’. This web project called ‘Lead Funnel’ is used for different segments of the market and, therefore, the branding and content are adjusted manually. I was tasked with generalising it and making it easily adjustable with just a single configuration so that any new Lead Funnel project can be deployed quickly in the future.


  • Extension of various software projects
  • Bug-analysis and fixing bugs
  • Deployment on the production server

Technologies used

  • React.JS
  • Symfony 3

Employment - Medici Living Group

Berlin, September 2015 – November 2017

Starting as a Junior Developer, it only took me a short while to acquire enough expertise to begin making architectural and visual (design) decisions as the Lead Developer in various software projects.


  • Planning, developing and maintaining a variety of web projects
  • Code analysis and debugging
  • Server setup (local & stage systems)
  • Trouble shooting, as well as problem resolution
  • Specialist support for my colleagues in development and technology
  • Technical documentation & manuals

Technologies used

  • Symfony 3
  • jQuery
  • React.JS

Apprenticeship - Deutsche Rentenversicherung Bund

Berlin, September 2012 – July 2015

My career as a software developer commenced with an apprenticeship at the Deutsche Rentenversicherung as a ‘Fachinformatiker für Anwendungsentwicklung’ (Computer Scientist for Application Development).


  • Planning and development of various software projects
  • Expansion of the company intranet
  • Management of a fictitious company, in order to understand a true commercial process
  • Negotiating with internal clients about products from specification to implementation
  • Insights into several development environments and languages
  • Regular training courses and seminars relating to software development