Michal Salajka, Linked Data Developer in Leipzig, Saxony, Germany
Michal Salajka

Linked Data Developer in Leipzig, Saxony, Germany

Member since June 24, 2018
Michal is a full-stack developer who enjoys creating well-tested responsive web applications. He contributes to open-source projects including social networks for hospitality exchange, collaboration, and food-sharing. He loves to learn by doing and to experiment with new ideas, concepts, and technologies. He enjoys collaboration and sharing, and he approaches work as play.
Michal is now available for hire




Leipzig, Saxony, Germany



Preferred Environment

Vim Text Editor, Linux, Git

The most amazing...

...project I've created is a tool for visualizing and sharing abstract mathematics knowledge as a directed acyclic graph.


  • Full-stack Developer

    2016 - 2020
    • Implemented collecting statistics with Grafana and StatHat.
    • Fixed security bugs. Improved member security by implementing an improved algorithm for randomizing user location.
    • Reviewed code and supported other contributors in learning code base and related technology.
    • Implemented displaying user statistics (i.e., response rate and response time) in user profiles.
    • Created endpoints for API written in Node.js and Express.js.
    • Wrote automatic tests for API following a practice of behavior-driven development (BDD).
    • Collaborated on building a reference system to improve member security.
    • Implemented the web application's internationalization with react-i18next. Supported other contributors.
    • Progressed with the migration of the web app from Angular.js to React. Supported other contributors.
    Technologies: React, MongoDB, Angular, Express.js, Node.js
  • Full-stack Developer

    2018 - 2018
    Karrot.world (volunteering)
    • Implemented emoji reactions to posts in both Django API and Vue.js app following the practice of Behavior-driven Development.
    Technologies: Vue.js, Django, Python
  • Co-founder and Developer

    2015 - 2018
    • Designed and built a major part of a REST API using Express.js and Node.js.
    • Created a data model based on a social graph using ArangoDB.
    • Designed and built the majority of a front-end app using Angular 5 and TypeScript.
    • Created detailed tests following the practice of behavior-driven development (BDD).
    • Performed server administration (Debian, nginx).
    Technologies: TypeScript, JavaScript, ArangoDB, Angular, Express.js, Node.js


  • ditup.org

    Platform connecting people for collaboration.

    REST API written in Node.js, Express.js, and ArangoDB. The app is written in Angular 5+.

    User data are stored as a social graph.

    Users can find each other based on subjects they care about.

  • Influenced

    A web app that visualizes how well-known people influenced each other.

    Based on linked data from dbpedia.org.

    Main technology: React, redux, d3, SPARQL.

    In collaboration with Agata Andrzejewska (https://www.toptal.com/resume/agata-andrzejewska).

    Open source.

    App runs at https://influenced.livegraph.org

  • Osm2pdf

    A Node.js global package for downloading openstreetmaps.org maps to a PDF file. It downloads either a map of a track provided in GPX format or a rectangular area specified by its GPS coordinate boundaries.

  • Trustroots Scraper

    A web crawler that collects user contacts of https://trustroots.org in order to display a social graph.

    Written in JavaScript (Node.js).

  • Cellular Encoder

    This web tool can encrypt and decrypt messages using the randomness created by elementary cellular automatons.

    The original idea is based on Steven Wolfram's book A New Kind of Science.

    Written with Angular and HTML Canvas.

    The app can be seen at https://mrkvon.github.io/narozeninova/

    It's a birthday present.

  • Minimalistic Blogging System

    A minimalistic blogging system written in Golang.

    Data managed with JSON and Markdown.

    It was a hobby project to play with Golang.

    Runs in production on author's personal website.


  • Languages

    JavaScript, Python, TypeScript, HTML, CSS, SPARQL, RDF
  • Frameworks

    Express.js, Angular, Django, JSON Web Tokens (JWT), Redux
  • Libraries/APIs

    Node.js, React, NgRx, Vue.js, GatsbyJS, D3.js
  • Tools

    Git, Vim Text Editor
  • Paradigms

    Behavior-driven Development (BDD), REST
  • Platforms

    Linux, Amazon Web Services (AWS)
  • Storage

    MySQL, MongoDB, ArangoDB
  • Other

    AWS, Linked Data, Semantic Web, Solid Apps (solidproject org)


  • Completed courses towards a bachelor's degree in Physics
    2008 - 2012
    Charles University - Prague, Czech Republic
  • Completed courses towards a bachelor's degree in Environmental Sciences
    2007 - 2012
    Charles University - Prague, Czech Republic

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