Bartosz Chodnicki, Developer in Warsaw, Poland
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Bartosz Chodnicki

Verified Expert  in Engineering

Software Developer

Warsaw, Poland
Toptal Member Since
April 8, 2022

Bartosz (Bart) is a passionate back-end developer who enjoys the challenge of creating high-traffic applications. He is a fan of building microservice applications with tight integrations to machine learning platforms and streaming processing to optimize business impact. His products handle hundreds of millions of active users and have high-scale push notifications and ML models that make predictions. He is happiest transforming ideas into apps and seeing users enjoy the tools he has built.


Scala, Play, Akka, Akka Actors, Akka Streams, Functional Programming, gRPC...
Scala, Akka, Akka Actors, Play, Spark
Java, Python 3, PHP, Symfony, Django, Flask, Akka, Lua, Apache Kafka, MySQL...




Preferred Environment

Linux, IntelliJ IDEA, Scala, Apache Flink

The most amazing...

...tool I've developed is a streaming application based on Apache Flink that can detect "not nice" or "inappropriate" users.

Work Experience

Senior Scala Developer

2020 - 2022
  • Developed microservices that handle hundreds of millions of active users.
  • Created streaming pipelines for real-time alerts.
  • Built an MLOps platform firmly integrated with other microservices.
Technologies: Scala, Play, Akka, Akka Actors, Akka Streams, Functional Programming, gRPC, REST, Apache Kafka, Cassandra, Redis, Elasticsearch, Kubernetes, Cloud, Google Cloud Platform (GCP), Prometheus, Grafana, Jenkins, Spinnaker, Flink, Machine Learning Operations (MLOps)

Senior Scala Developer

2020 - 2020
  • Developed web service that contain machine learning models used for making predictions.
  • Migrated and cleaned old repositories to newer technologies.
  • Completed benchmarks and tests of different technologies to meet client requirements.
Technologies: Scala, Akka, Akka Actors, Play, Spark

System Architect

2015 - 2019
  • Designed and developed many services used for different marketing channels.
  • Developed a high-scale push notification system used for advertisement campaigns.
  • Designed and optimized databases used with our applications.
  • Analyzed network traffic with bot detection streaming algorithms.
  • Communicated with the business, planned project roadmaps, and worked in an Agile environment.
Technologies: Java, Python 3, PHP, Symfony, Django, Flask, Akka, Lua, Apache Kafka, MySQL, MongoDB, Redis, Pandas, Git, CI/CD Pipelines, Jenkins, Angular, Celery, Flink

Full-stack Developer

2011 - 2015
  • Developed a network quality monitoring system that allows the creation of different testing scenarios and presents results on a web platform.
  • Developed active robots based on the Linux operating system that allows network monitoring from an E2E perspective.
  • Deployed a network monitoring system in various European countries.
  • Contacted clients, gathered system requirements, planned the roadmap, and assisted with system usage.
Technologies: PHP, Linux, jQuery

ML Server with ZIO
This is an example of how to create an HTTP server for serving ML prediction with the ZIO HTTP library and MLeap. It enables the use of machine learning models made in Python or Spark with Scala applications. The project shows how to load the ML model saved in a file and use it to make predictions for incoming HTTP requests.
2007 - 2012

Bachelor of Science Degree in Engineering of Informatics Systems

Warsaw University of Technology - Warsaw, Poland


Akka Streams, jQuery, Pandas, ZIO


Git, Flink, Jenkins, Celery, Grafana, IntelliJ IDEA


Play, Akka, Angular, Symfony, Django, Flask, Spark, gRPC


REST, Microservices, Functional Programming


Scala, PHP, Python 3, Java, Lua


MySQL, MongoDB, Redis, Cassandra, Elasticsearch


Linux, Apache Kafka, Kubernetes, Google Cloud Platform (GCP), Spinnaker, Apache Flink


Software Development, Akka Actors, Cloud, CI/CD Pipelines, Prometheus, Machine Learning, HTTP, Machine Learning Operations (MLOps), MLeap

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