---
# System prepended metadata

title: GREG RYNKOWSKI

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# GREG RYNKOWSKI

hackmd-resume[at]rynkowski[dot]pl<br/>

[Website](https://rynkowski.pl) | [Github](https://github.com/rynkowsg) | [LinkedIn](https://linkedin.com/in/rynkowsg/) | [Twitter](https://twitter.com/rynkowski_dev)


### About me

With nearly 13 years of commercial experience and a background in programming that predates my professional career, I have honed a solid understanding of algorithmics and programming models. My professional journey began delving into the internals of mobile operating systems before transitioning to the mobile apps space and ultimately landing in backend/fullstack development.

Throughout my career, I've wielded a diverse array of languages and platforms, including C++, Java, Kotlin, and most recently, finding Clojure/Script to be both effective and enjoyable to work with.

Driven by a passion for productivity, I am perpetually on the lookout for tools that offer greater leverage and advocate for practices that maintain physical well-being and mental clarity.


### experience (Clojure)

* **_Obrizum - Senior Software Developer - 05/2023 to 11/2023_**

    Project: Adaptive learning platform
    - maintanance of existing product
    - tech: Clojure/Script, Babashka, re-frame, Fulcro, AWS Lambda, Datomic Ions


* **_ServedUp - Senior Android Developer (Contract) - 10/2021 to 11/2022 (1 yr 2 mos)_**

    Project: POS app - android project, but I used Clojure for various reasons:
    - scripting of CI/CD
    - automating internal reporting about devices fleet
    - tech: Clojure, Sunmi, AWS DynamoDB, S3, Sentry, CircleCI


* **_CGT tax calc (personal project) - Sole Developer - 2021, 2024_**
    
    Project:
    - domain heavy algorithm to calculate Capital Gains Tax in the UK
    - tech: Clojure, malli, clerk, Datomic


* **_YouView - AWS micro-services - Cloud Services Engineer (Contract) - 06/2018 to 10/2018 (5 mos)_**

  Project: Maintenance and development of micro-services
  
  The project involved:
  - building micro-services in CQRS model from scratch
  - exposition to several AWS services: EC2, ECS, CloudFormation, Kinesis
  - introducing Clojure to junior team members
  - tech: Clojure, Postgres, AWS, CircleCI


### experience (other)

* **_ServedUp - Senior Android Developer (Contract) - 10/2021 to 11/2022 (1 yr 2 mos)_**

    Project: POS app - maintanance and development
    - led 2-3 people team (incl. myself)
    - carried on architecture redesign on the app due to accrued tech debt
    - tech: Android SDK, Material Design, Kotlin, Coroutines, Dagger 2, REST, AWS IoT, Sunmi devices, ESC/POS printers


* **_ServedUp - Senior Android Developer (Contract) - 07/2020 to 11/2020 (5 mos)_**

    Project: POS app
    - built single-handedly from scratch
    - depends on mode the app was capable to make orders, manage sales and/or delivering orders to kitchen/bar.
    - first device was ready for field-testing within 2-3 months from starting the project.
    - tech: Android SDK, Material Design, Kotlin, Coroutines, Dagger 2, REST, AWS IoT, Sunmi devices, ESC/POS printers


* **_ChargedUp - Senior Android Developer (Contract) - 09/2019 to 05/2020 (9 mos)_**

    Project 1: Large-screen device renting power banks in Westfield shopping centres
    
    - Built single-handedly from scratch
    - The project involved:
        - serving UI,
        - serial port communication (incl. discovering the protocol by reverse engineering)
        - IoT communication,
        - building sub-system for delivering updates,
        - building sub-systems for onsite & remote admin operations.
    - First release was scheduled for Christmas and was delivered on time (~3 months).
    - Tech: Android SDK/NDK, Kotlin, Coroutines, RxJava, Dagger, REST, AWS IOT
    
    Project 2: Refactor of legacy mobile app (app for ordering the rentals)
    
    - A one-man project. 
    - My main focus was on improving the quality of the codebase by revisiting all features, reduction and simplification.
      The final outcome was:
      - app modularised by separation of features
      - app with a solid object lifecycle management (with Dagger 2) and control over async operations (with Coroutine scopes).
      - app size reduced by over 60%
     - Tech: Android SDK, Kotlin, Java, Coroutines, Flow, Dagger 2, REST


* **_YouView - Android Hybrid app - Senior Android Developer (Contract) - 01/2018 to 06/2018 (6 mos)_**

  Project: Android TV container app hosting an existing HTML/JS TV app
  
  - a one-man project, built from scratch
  - it involved:
      - building two-directional communication bridge between a native container and HTML/JS app,
      - proxying network communication,
      - bringing on a few AOSP modifications.
  - the project succeeded, earned recognition and grew in the team after the initial incubation stage.
  - tech: Java, Kotlin, TypeScript, RxJava, Dagger, Android SDK, Android TV, Clean Architecture


* **_Hopster  - Lead Core Engineer - 06/2017 to 12/2017 (8 mos)_**

  Project: Cross-platform multimedia app - stewardship and re-architecture
  
  - Some of the accomplishments:
      - Redesigned the build process of the main app and its modules. 
      That change improved build time, reduced crash rate (by improving ABI
      compatibility) and made them work with modules much easier.
      - Introduced a CI process with running jobs on Linux in cloud and Mac locally
      - Synced to the latest version of Cocos2d-x from quite an obsolete version of
      engine with plenty of company own patches (including an upgrade of Spine engine)
      - Helped CTO in making his decisions related to the mobile app.
      - Awoke at developers the spirit of ownership and continues self-growth.
  - tech: C++, Java, Objective-C, JNI,  Python, cocos2d-x, Android SDK/NDK, GCP, Jenkins


* **_Hopster - Mobile Engineer - 11/2015 to 5/2017 (1 yr 7 mos)_**

  Project: Cross-platform multimedia app - development and maintenance
  
  - Some of the activities:
      - building animation rich features
      - Integrating external tools/SDKs, including marketing tools like Facebook SDK, Google Analytics, Swrve, Tune (MAT), Branch.io
      - Helped marketing team in designing and running campaigns as well as interpreting data
      - Working closely with web frontend team on building React-based screen running inside of Android Webview and UIWebView
      - Accomplished to introduce quite a lot of good practices in an existing counting 8 people mobile team
      - Leading up the chain of command in terms of mobile app decisions.
  - tech: C++, Java, Objective-C, JNI, cocos2d-x, Android SDK/NDK


* **_Samsung - Tizen Frameworks - Software Engineer  - 1/2012 to 3/2015 (3 yr 3 mos)_**

  Project: web-runtime of Tizen OS - *1/2013 - 3/2015 (2 yrs 3 mos)*
  
  - goal to provide an environment similar to modern-day environments provided by web browsers to plugin developers.
  - main parts: platform frameworks, installation mechanism, runtime environment, app security.
  - it involved usage of:
      - Linux programming techniques,
      - low-level drivers,
      - popular open source projects like browser rendering tools (WebKit, Blink, Chromium),
      - JavaScript engines (JSCore, V8), multimedia framework (GStreamer)
      - windowing systems (X11, Wayland),
      - variety of programmable boards like Odroid, Raspberry, and custom once.
  - other activities
      - open source licenses compliance using 'Black Duck' software
      - conducting algorithmic training
  - tech: C++98/11, JavaScript, Bash, CMake, Gerrit, Tizen OS, boost

  Project: P2P library for sharing audio/video - *8/2012 - 12/2012 (5 mos)*
  
  - it involved:
      - usage of P2P protocols (XMPP, Jingle) and networking protocols (TCP/IP, STUN, TURN, ICE)
      - focusing on performance of transmission what involved
  - tech: Java, C++, JNI, Bash, Android NDK, p2p, XMPP, libjingle, SVN

  Project: Samsung stock apps - *1/2012 - 07/2012 (7 mos)*

  - development of a custom launcher app
  - development of a photo editor app
  - maintenance of Samsung stock application and platform frameworks
  - tech: Java, C++, Android SDK/ NDK, AOSP, JNI, Perforce


*You may notice some gaps in my employment history. These occur because I periodically take breaks between long-term roles. Every time I find these intervals to be incredibly productive and enlightening, allowing me to explore both areas related to my profession and entirely different fields.*

### education

|||
|---|---|
|2008-2012|Bachelor of Software Engineering - Computer Science<br>Warsaw University of Technology (Poland)|
|2007-2008|Participant in Olympiads in Informatics (Poland)|


### other

- Living in Uruguay
- Languages: Polish, English, Spanish (basics).
- Hobby: squash, chess, BJJ
- Husbend and father of three.

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_Updated on 04 Apr 2024._
