Kristof Leroux, Developer in Genk, Belgium
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Kristof Leroux

Verified Expert  in Engineering

Blockchain Developer

Genk, Belgium
Toptal Member Since
November 10, 2022

Kristof is a professional developer with almost 20 years of experience in the IT industry. He specializes in developing iOS and Android mobile apps with C, C++, C#, .NET, Ionic, TypeScript, Ruby on Rails, and Python. His expertise also includes data, machine learning, and blockchain development with Solidity on Ethereum and Tezos. Kristof launched and sold two startups, one for hosting and the other for social media management.


ENGIE Impact
Python 3, Flask, Pytest, PostgREST, TimescaleDB, Amazon Kinesis, Apache Kafka...
Python 3, FastAPI, Pydantic, Pytest, Azure Cosmos DB, MongoDB, Apache Kafka...
Go, Gorilla, Gorm, Amazon Web Services (AWS), Ethereum, Solidity...




Preferred Environment

MacOS, Linux, Python 3, Python 2, C, Solidity, JavaScript, React, Amazon Web Services (AWS), SQL, Blockchain, Smart Contracts, Ethereum, Bots, Blockchain Platforms, Cryptocurrency, Non-fungible Tokens (NFT), CTO

The most amazing...

...thing I've launched is a startup in 2012, winning the first edition of Startupbootcamp Amsterdam.

Work Experience

Freelance Senior Python Engineer

2021 - 2022
ENGIE Impact
  • Developed and maintained the power feature team's applications, such as Hedgie, AssetRep, and Opnl, used by traders to hedge risk using futures contracts.
  • Delivered many solutions using tools such as Python, Flask, pytest, Postgres, TimescaleDB, Kinesis, Vue, GitHub, Drone CI, Azure, AWS, Grafana, Kibana, Elasticsearch, Sentry, Kubernetes, Docker, and Jira.
  • Developed and maintained apps of a renewable energy services team, including Mon Pilotage Elec (MPE), Tegami, and GEPO, to monitor and control the electrical grid's stability with activation or curtailment if needed.
Technologies: Python 3, Flask, Pytest, PostgREST, TimescaleDB, Amazon Kinesis, Apache Kafka, Vue, GitHub, CI/CD Pipelines, Azure, Amazon Web Services (AWS), Grafana, Kibana, Elasticsearch, Sentry, Kubernetes, Docker, Jira, Slack, Teams

Freelance Senior Python Engineer

2020 - 2021
  • Contributed to various automated investment solutions for a European fintech company helping financial institutions retain their clients by defending their market positions against nimble B2C fintech disruptors.
  • Developed and maintained back-end services with Console API, Entity, Storyteller, Elasticsearch, and Interactive Brokers integration. These services were part of the robo-advisor and asset management platform.
  • Used different tools and technologies, including Python, FastAPI, pydantic, pytest, Cosmos DB, MongoDB, Kafka, gRPC, GitLab CI/CD, AWS, Kubernetes, Docker, Helm, Istio, Jira, Miro, and many more.
Technologies: Python 3, FastAPI, Pydantic, Pytest, Azure Cosmos DB, MongoDB, Apache Kafka, Elasticsearch, gRPC, Protobuf, GitLab CI/CD, Azure, Amazon Web Services (AWS), Interactive Brokers API, Kubernetes, Docker, Helm, Istio, Jira, Miro, Fintech

Senior Back-end Developer

2018 - 2019
  • Worked for TiiQu, a blockchain-based platform that uses immutable, verifiable blockchains to create digital "passports," i.e., helps to prove identity, previous work experience, qualifications, performance metrics, and so on.
  • Started when they were bootstrapping and helped with the architecture, DevOps, the CI/CD pipeline, smart contract development, and security proofing.
  • Wrote technical white papers and other documents.
Technologies: Go, Gorilla, Gorm, Amazon Web Services (AWS), Ethereum, Solidity, Smart Contracts, Ethereum Smart Contracts, Web3.js

Automata Studio

I applied cutting-edge machine learning and deep learning to asset selection and portfolio management while managing risk levels. I also predicted the evolution of price, volume, and volatility of indices and assets while performing algorithmic and high-frequency trading. Some of the technologies used in this project include Python, NumPy, pandas, TensorFlow, PyTorch, Keras, Apache Spark, Kafka, Databricks, MLflow, microservices, Flask, and React.


I cofounded SocialExpress, a social business intelligence solution to bridge the gap between consumers and management.

We participated at Startupbootcamp Amsterdam and became one of the ten finalists. In two years, we raised almost one million euros and had a lot of media coverage.

I was the CTO and developed the back end in Python with Flask. We used Machine Learning techniques like advanced sentiment analysis and topic modeling with Latent Dirichlet Allocation. I managed a team of five developers.
2003 - 2005

Master's Degree in Artificial Intelligence

Maastricht University - Maastricht, The Netherlands

2000 - 2003

Bachelor's Degree in Computer Science

Hasselt University - Diepenbeek and Hasselt, Belgium


Executive Program in Algorithmic Trading (EPAT)



PostgREST, NumPy, Pandas, Web3.js, Node.js, React, Vue, TensorFlow, PyTorch, Keras, Pydantic, Protobuf, Interactive Brokers API


Pytest, GitHub, Slack, MATLAB, Grafana, Kibana, Sentry, Jira, Kafka Streams, GitLab CI/CD, Helm, Istio, Miro, Gorilla


MacOS, Linux, Blockchain, Amazon Web Services (AWS), Software Design Patterns, Docker, Ethereum, Blockchain Platforms, Apache Kafka, Azure, Kubernetes, Databricks


Flask, Apache Spark, gRPC, Gorm, Django, Bootstrap, Knockout (Knockout.js), AngularJS


Python 3, Python 2, C, Solidity, SQL, Rust, JavaScript, Go


Elasticsearch, PostgreSQL, Databases, Azure Cosmos DB, MongoDB


Microservices, Management


Cryptocurrency, Software Development, Algorithms, Data Structures, Matrix Algebra, Software Engineering, Machine Learning, Neural Networks, Artificial Intelligence (AI), Smart Contracts, Bots, Fintech, Non-fungible Tokens (NFT), CTO, Algebra, Calculus, Informatics, Artificial General Intelligence (AGI), Philosophy, TimescaleDB, Amazon Kinesis, CI/CD Pipelines, Teams, Delta Lake, MLflow, FastAPI, Quantitative Finance, Backtesting Trading Strategies, Finance APIs, Markets, Risk, Models, Time Series Analysis, Ethereum Smart Contracts, Flask-Admin, Natural Language Processing (NLP), Generative Pre-trained Transformers (GPT)

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