KSI - Software developer`s portfolio
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Full-stack developer, front-end, back-end. Full-stack developers outsourcing. Full stack developer
& freelancer...
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Application development


  • HTML5, XHTML, HTML4 - document structure and content.
  • CSS3, CSS - cascading style sheets.
  • JavaScript ( vanillaJS ) - To avoid overloading the website with unnecessary scripts I always try to use pure JS. Of course, there are situations when such actions are not profitable and only then I use for external Frameworks.
  • WebComponents - integrated with any modern browser tool to create your own universal components. Components supports: templates, reactivity, objects are hermetic.
  • WebSockets - when a WEB application requires constant communication with the server.
  • WebAudio - audio recording, processing and playback.
  • WebAssembly - if the application needs a lot of computing power and JS is too slow.



  • PHP - is my main back-end programming language. I use it to create CMS tools, websites but also as a support for back-office or CRM applications.
  • C/C++ - if I need to write something that is small and fast.


Desktop applications

  • Embarcadero C++ Builder / Delphi 10.X - cross-platform environment that allows to create native applications for all popular operating systems.
  • C# - Visual Studio Windows Forms (if there is such a need to write something in it).
  • Java + Swing - only small applications (more as a hobby).
  • OpenGL - 3d graphics creation.
  • SDL - universal cross-platform libraries for graphics, audio and external devices.
  • BASS - libraries for efficient audio signal processing and playback


Mobile applications


Communication between systems

When there is a need to integrate an application with an external system then I can use:


  • REST-API - a simple way to communicate between systems working in network. Communication based on HTTP/HTTPS, usually using JSON format for data transfer.
  • SOAP - an older, very formal and powerful way to exchange information between applications.
  • JSON, CSV, XML, EXCEL, ODT, TXT - data exchange formats.
  • TCP/IP, UDP - good solution for fast and continuous communication between servers or applications.
  • RS232 / RS485 / RS422/ I2C - serial communication usually used for communication with peripheral devices such as fiscal printers, ID card readers, automation controllers (also via WiFi or Ethernet).
  • MT940 - specialized format for exchanging information, e.g. from bank statements.


API, data sources, external services

  • Google Maps API - provider of a map service system,
  • MapBOX API - second very good provider of a map service system,
  • Deepl.com - API for automating text translations based on neural networks, very good for specialized texts,
  • Google Translator API - for translations,
  • Przelewy24, dotPay - online payments systems popular in Poland,
  • Stripe.com, PayPal.com - universal payment systems with international range,
  • MDSWS - Polish database of tourist offers.


Systems and platforms

I develop applications running under the control of the following operating systems or platforms:


  • Microsoft Windows,
  • Linux,
  • MacOS / iOS,
  • Android,
  • AVR - Microchip Studio / KiCad,
  • 8051 - Small Device Compiler / SDCC,
  • DOS / FreeDos - Assembler / Pascal / C++.



Applications that require cooperation with database I build using:


  • MySQL - popular cheap to maintain database that gives most of the necessary functionality needed to work on large collections of information.
  • Oracle - for use where it is required.


System design

When designing more complex applications I use tools like:


  • Visual Paradigm - UML diagrams,
  • Swagger - preparing API documentations,
  • MySQL WorkBench - database structure / ERD.