Leonard Ossa

Software Development Engineer in Test / Senior Quality Engineer


I'm passionate about learning, automating daily tasks, and optimizing tools for efficiency. In my career, I've developed internal tools that streamline operations and have a strong background in creating and sharing knowledge bases. I excel in OSINT, capable of producing detailed software solution reports. I've led startup projects, notably an award-winning innovative mobile ANC device and developed a smart white-cane prototype for the visually impaired, recognized in Puls Biznesu. I advocate for FLOSS, use LineageOS, prioritize privacy, and am keen to expand my skills in software development, automation, reverse-engineering, and AI.


  • Expert
    Software Development Engineering in Test (SDET)
    Quality Engineering
    Quality Assurance
    Automated Testing
    E2E Testing
    System Testing
    API testing
    Selenium WebDriver
    Python 3
    Manual Testing
    Chrome DevTools
    Conventional Commits
    Clean Coding
    Software Development Life Cycle
    Cybersecurity Aware
    Problem solving skills
    Critical thinking
  • Advanced
    HTML 5
    Postman / newman / Insomnia / hoppscotch
    Behavior Driven Development
  • Competent
    reverse engineering
    CI/CD - Continuous Integration / Continuous Deployment
    Mobile app testing
  • Beginner
    Android development


  • Polish

  • English




2018-08 - 2023-11

Senior Software Quality Assurance Engineer, Nethone

Building automated testing framework from scratch using Playwright

Senior Software Quality Assurance Engineer, Poly

Being part of the architect group that was responsible for desigining and implementing testing framework from scratch. I was one of the main creators of the framework and introduced then implemented novel solutions (like sharing the same code base for an application tested on different platforms). In this position I had to deal with C++ code (that I used in my programming career) and multiple platforms (including iOS, Android, MacOS, Windows, ...) and hardware (headset, webcams, conference devices).

  • Being core of the architect team.
  • Being a mentor/teacher for other coworkers.
  • Introducing new concepts to the team and implementing them
  • Doing a lot of code review and mentorship
  • Setting standards for code quality and maintaining it
  • Doing technical part of candidate interview

QA Engineer, Boldare

I was part of the team responsible for the development of data-science webapp for external customer. At the team I was using Python and TypeScript for creating tests. I was also published on company website https://www.boldare.com/blog/quality-assurance-for-ux/

QA Tester, T-Mobile

I was solely responsible for designing and implementing the testing process, worked with 3 different teams in two departments. I was the only tester in the department at the moment of joining the team, making myself engaged in the testing process and introducing and integrating that process into the company's procedures according to Agile methodology.

  • Successfully implemented and integrated the testing process into the Agile teams.
  • Created working API health check (based on Postman) that was monitoring API and let developers postpone writing the custom solution and save time. Provided the team with detailed reports from API monitoring.
  • Created an internal side-project based on Microsoft Stream that let employees download and play training videos locally instead of playing them from the website (T-Mobile MS-Stream downloader). That helped people with poor connection quality, so they can watch without video playback stuttering.

Software Engineer, Technica Engineering

Using a mix of technology - including Python, C# and IronPython to write software that parsed, analyzed and processed data based on complex automotive protocols (LIN, CAN, FlexRay). That required learning and a deep understanding of data structure and functioning of industry-specific protocols at the hardware (bit-precisely) level.

  • By changing the previously used threading technique (manual creating&managing threads) to thread pooling I was able to significantly improve the performance of the software (C#). I used the knowledge acquired at one of my previous position at SENSE Software, where I was first introduced to this technique.
  • Wrote custom templates to Python Sphinx, and generated beautiful HTML documentation for a project
  • Wrote documentation for previously undocumented Python code

Manual Tester, Miinto

Being in the position of Manual Tester while having skills to write bash (but mostly used fish) scripts and automate my work I created an internal custom repository of tools accelerating my work a few times. Scripts I wrote used SSH, some of them run commands remotely on servers or parsed data fetched from servers like script using multitail to grab logs from a few different machines in real-time with highlighting custom syntax specifically wrote for this project.

  • Testing Front-end, investigating bugs and proposing solutions
  • Using PostgreSQL but also NoSQL database - Redis including simple operations on a database
  • Created custom scripts (all of those were internal side-projects) including:
  • Scripts for remote logs scraping , reading and filtering (using multitail)
  • Scripts for remote SQL database updates
  • Designed and implemented an absolutely new solution for tracking testers' tickets that allowed to check which tester was handling a specific customer order
  • Scripts for manipulating Redis database
  • Scripts for interacting with Google Sheets
  • Scripts for deploying environments for testers
  • Providing training for new testers in the team, but also:
  • Recording training sessions and:
  • Creating Knowledge Base for testing team

C# Developer, SENSE Software

Working in this position I was responsible for implementing new features into the software.

  • I was responsible for implementing parser&interpreter that allowed users to evaluate their own functions in the software (similar to Excel functions).
  • Testing software, investigating, reporting and fixing bugs


Main prize for the best startup project, WAW.ac - Warsaw Technological Startup Accelerator with hub:raum T-Mobile


Prize was for inventing, building and presenting working prototype of 'Husher' - mobile ANC (Active Noise Cancellation) device. The whole process from idea to present working prototype took around 4 days.


Cognitive science and neuroscience


I'm deeply fascinated with brain and its capabilities. I read a lot about mind, intelligence (human and animal one) and methods to improve intellectual functioning.



Biohacking allows me to live healthier and more productive life on every day basis.