Radek Ostrowski
Verified Expert in Engineering
Ethereum Developer
Phuket, Thailand
Toptal member since September 24, 2014
Radek is a certified Toptal blockchain engineer particularly interested in Ethereum and smart contracts. In the fiat world, he is experienced in big data and machine learning projects. He is a triple winner in two different international IBM Apache Spark competitions, co-creator of PlayStation 4's back end, a successful hackathon competitor, and a speaker at conferences in Australia, Poland, and Serbia.
Portfolio
Experience
Availability
Preferred Environment
GitHub, MacOS, Unix
The most amazing...
...achievement I've had is winning two international Apache Spark competitions run by IBM.
Work Experience
Blockchain Consultant
StartOnChain
- Engaged with clients wanting to enter the blockchain space, especially in the Ethereum ecosystem.
- Won a prize for my "Time Locked Wallet" demo project in ConsenSys, a uPort Blockchain and Identity hackathon.
- Designed and deployed smart contracts for tokens and ICOs including token vesting, refund vaults, and multi-signature wallets.
- Performed smart contract security audits both automated and manual.
Ethereum Engineer
British Asset – Kauri Crypto (via Toptal)
- Created and deployed a staking contract for the platform token.
- Created a demo DApp for the staking contract.
- Implemented and deployed the graph for the staking contract tracking all events and allowing more advanced queries.
Ethereum Engineer
Zipmex Exchange (via Toptal)
- Created an upgradable erc20 token contract using a call delegate proxy.
- Deployed the project to mainnet, verified on Etherscan, and provided instructions to the team on how to use it.
Blockchain Engineer
LLPS, LLC (via Toptal)
- Built a prototype of a real estate-backed loans platform.
- Designed and built the Ethereum smart contracts forming the back end of the platform.
- Created a user interface to the blockchain back end using React and Drizzle.
Blockchain Engineer
Grayblock (via Toptal)
- Helped to design and build a POC platform leveraging blockchain to improve electricity generation finance.
Blockchain Engineer
IDEX – Aurora Labs S. A. (via Toptal)
- Investigated various optimizations to Ethereum transaction throughput and gas cost for IDEX, currently the biggest on-chain exchange.
- Prototyped several optimizations including scheduling and specialized smart contracts.
Solidity Expert
Coinuma SL (via Toptal)
- Helped to integrate Ethereum into the cryptocurrency exchange being built.
- Demonstrated wallet generation, ether and token transfers, balance checks, and listening for events.
- Advised on best security practices.
Blockchain Engineer
Fan Hero (via Toptal)
- Provided consultancy on Ethereum.
- Researched the use of permissioned blocks and IPFS.
- Investigated transferring tokens without ether.
- Prototyped a token contract.
Ethereum/Solidity Developer
Kryptonex LLC (via Toptal)
- Helped to integrate Ethereum and ER20 tokens into an exchange that is currently being built. It included address generation, token listing, and basic wallet operation related to ether and tokens using Web3.js.
Big Data Engineer
Commonwealth Bank of Australia
- Provided consultancy on big data technologies and data science.
- Architected and designed scalable solutions.
- Developed solutions mainly with Apache Spark and Scala.
- Employed machine learning techniques to maximize profit.
- Led a team to victory in an internal hackathon—developed a Slack bot for knowledge discovery, deployed on AWS.
Big Data Engineer
Taulia, Inc. (via Toptal)
- Designed and built a new generation of Taulia’s data analytics platform.
- Effectively processed financial data and extracted useful information both in batch and real time.
- Built the platform in Scala, Spark Streaming and SQL, Cassandra, Kafka, Docker, and Redshift, running on Kubernetes on AWS.
Big Data Engineer
Method Mill
- Helped integrate various data sources on a large scale.
- Built a pipeline from MySQL to Amazon Redshift.
- Created a syncing tool for Amazon S3.
Big Data Engineer
Max2, Inc. (via Toptal)
- Helped design and build a community-powered venue discovery platform offering personalized recommendations, planning with friends, and curated and real-time information.
- Used SparkSQL with DataFrames for data ingestion and Spark Streaming and MLlib for analytics.
- Coded in Scala with Akka and Kafka and run on Mesos.
Senior Developer/Docker Evangelist
Tesco Bank
- Introduced Docker to the development environment.
- Helped improve the CI pipeline.
- Extended the credit card portal.
- Improved the user journey experience for a loan portal.
Big Data Engineer
Expedia, Inc.
- Helped to automate the build and run process.
- Prototyped with Apache Spark.
- Updated existing Hive and MapReduce workflows.
Senior Software Developer/Team Leader
Sony
- Built a production RESTful Java web service for Sony devices and platforms mainly for Sony PS4 and 4K-TV handling hundreds of thousands of transactions.
- Developed on top of Spring Framework and Cassandra.
- Offered authentication and authorization capabilities based on OAuth2.
- Focused on quality of the code by employing unit testing with 100% code coverage, BDD with Cucumber, code reviews with GitHub pull requests, and Jenkins.
- Produced a project collecting, analyzing, and visualizing statistics from Sony devices. The data is stored in Amazon S3 and processed using Hadoop (MapReduce and Hive). The data collection server and the BI portals are Java based (Spring MVC and REST). I secured the access to the web services (by extending Spring Security) and the relational databases. Other technologies used include Apache Karaf (OSGi) and Maven.
- Worked on the “One Account – All Sony” global unified accounts integration project for Playstation and other devices.
- Led a team of three in Brussels and collaborated closely with the rest of the team in San Diego.
Senior Developer
DeltaDNA (GamesAnalytics)
- Tackled the challenges of real-time data collection, predictive analytics, data measurement, and user engagement for the millions of online and mobile computer game sessions, personalizing the user’s gaming experience and increasing retention and revenue as a result through optimized game design and individually targeted in-game messaging.
- Designed, developed, and provided continuous updates and enhancements of new features as part of an Agile in-house development team for the platforms and mobile SDKs.
Applications Consultant
EPCC (University of Edinburgh)
- Led “Work Package 3: Test, Delivery, and Support” from start to finish in an Excellent-rated, data-intensive research project for the EU.
- Designed and implemented the test platform, new software components based on Java, REST, Spring, Hibernate, and HDFS and extended existing software components such as OGSA-DAI during the lifespan of the project.
- Worked on a master of science in high-performance computing, “test infecting” the students by lecturing and leading tutorials on unit testing and extreme programming and Agile methods; also created and gave a lecture on cloud use cases.
- Developed a RESTful presentation layer based on Jersey for the software program OGSA-DAI.
- Designed and developed an iPhone application for the UK National Supercomputing Service.
- Fixed performance problems involving CUDA, C, JNI, and Java code and improved its graphical user interface via a spinout company.
- Contributed to the project investigating the usage of Hadoop/MapReduce and clouds (Amazon EC2/Eucalyptus) for the analysis of post-genomic data.
- Enabled the integration of the UKQCD community with the International Lattice Data Grid by implementing a web service layer in Java.
Experience
Topcoder/ConsenSys - uPort Blockchain and Identity Hackathon
https://github.com/radek1st/uport-time-locked-walletsMy Perfect Weather - IBM Spark Competition
Dipping into the Big Data River: Stream Analytics at Scale
https://github.com/radek1st/BigDataRiverhttp://data.yowconference.com.au/profile/?id=radek-ostrowski
Kaggle - Data Science Competitions
https://www.kaggle.com/radek1st* Top 6% (100/1984) in Expedia Hotel Recommendation
* Top 9% (84/979) in Outbrain Click Prediction
iWisps - IBM Spark Competition
Scala for Data Science
Contributions to Spark Notebook
https://github.com/andypetrella/spark-notebook/pull/191Contributions to Stubby4j
https://github.com/azagniotov/stubby4j/pull/50Contributions to the Spring Security OAuth
https://github.com/spring-projects/spring-security-oauth/commits?author=radek1stEducation
Master of Science (with Distinction) Degree in High Performance Computing
University of Edinburgh - Edinburgh, UK
Bachelor of Science (with Honors) Degree in Computing
Edinburgh Napier University - Edinburgh, UK
Bachelor of Science Degree in Physics with IT
Nicolas Copernicus University - Torun, Poland
Certifications
Architect Certification for Apache Cassandra
DataStax
Developer Certification for Apache Spark
Databricks
Java Web Services Certified Expert
Oracle
Skills
Libraries/APIs
Web3.js, Spark Streaming, Node.js, React.js, Drizzle
Tools
Git, Spark, Cucumber, Jenkins, GitHub, Splunk, Chef, Apache
Languages
Solidity, Scala, Java, Python, JavaScript, C++, Fortran, C
Frameworks
Truffle, Big Data Architecture, Play Framework, Spring, Hadoop, OAuth, Spark, Akka
Paradigms
Agile Development, Functional Programming, Scrum Master Consulting, Kanban Project Management, REST, Distributed Computing
Platforms
Android, Drupal Design, Blockchain, Ethereum, Docker, Linux, MacOS, Kubernetes, Hyperledger, R3 Corda, Apache Kafka, AWS, Amazon EC2, iOS, Unix, Web Development
Storage
NoSQL, Cassandra, Redshift, Hadoop, Amazon S3, VoltDB, Azkaban, Redis, MySQL
Other
Ethereum Smart Contract, Data Science, Machine Learning, Data Engineering, Freelance Design, Altcoin, Smart Contract Development, NFT, IPFS, Web 3.0, DApps, GRAPH, Compilers, Data Structures, Web3
How to Work with Toptal
Toptal matches you directly with global industry experts from our network in hours—not weeks or months.
Share your needs
Choose your talent
Start your risk-free talent trial
Top talent is in high demand.
Start hiring