Alexander Nikolaev
Verified Expert in Engineering
Machine Learning Developer
Alex is a software engineer with vast experience in data science. He has strong back-end engineering skills and loves digging deep into data to obtain valuable insights and hidden gems. He is an excellent communicator with proficiency in navigating teams to ensure successful project delivery. Alex's expertise lies in creating efficient end-to-end machine learning solutions with a strong understanding of business requirements and KPIs.
Portfolio
Experience
Availability
Preferred Environment
Jupyter, PyCharm, IntelliJ IDEA, Git, Linux
The most amazing...
...program I've developed is a machine learning model which reduced the company's losses due to fraud by USD $2.5 million a year.
Work Experience
Software Engineer
Agoda
- Developed an account protection API in Scala and Play, which is responsible for detecting suspicious activities in a user's account.
- Implemented a machine learning model for showing CAPTCHA, which reduced the number of false positives by 50%.
- Implemented a machine learning model for customer fraud detection, saving the company approximately 2.5 million USD a year.
- Supervised a team of six people in machine learning protocols.
- Implemented an anomaly detection framework for bots, and the detection of suspicious users. More specifically, this framework allowed the identifying of high-volume or credential stuffing attacks in near real-time.
- Consulted a wide range of teams on machine learning approaches, and helped develop a quick, and efficient POC.
- Developed a data replication mechanism across five data centers using Apache Kafka.
Data Scientist
Sberbank
- Implemented an analytical library in Python for a credit scoring models' validation.
- Automated ETL jobs.
- Developed the framework for anomaly detection in loan applications using TensorFlow.
- Consulted managers and executives on data science, and industry best practices.
- Organized events, and competitions for data scientists.
Software Engineering Intern
- Implemented efficient minimum engagement operators in an archive index using Apache Lucene, and Twitter EarlyBird.
Data Analyst
Yandex
- Developed look-alike models for ads targeting, and audience segmentation by behavior, age, and gender using Python, and Java.
- Gathered and pre-processed the data, trained the models, ran A/B testing, and followed through to production.
- Contributed to the development of an analytical framework.
- Improved performance of the age detection classifier by 10% (in terms of AUC).
Experience
Real-time Data Processing, and Analysis Using Raspberry Pi
Technologies used: Python (scikit-learn, Pandas, NumPy), SQLite, Apache Kafka.
Age Detection Based On Users' Behavior on Website
Technologies used: Python (scikit-learn, Pandas, NumPy), XGBoost, Vowpal Wabbit, MatrixNet.
Fraud Detection Pipeline
Technologies used: LightGBM, PMML, Scala Play, Apache Kafka, Couchbase, Docker.
Anomaly Detection Framework
Technologies used: Spark, Scala, DBSCAN, Grafana.
React-SPA
Technologies used: React, Redux, Saga, Webpack.
Skillset
Languages
Python, SQL, Scala, Java, JavaScript
Libraries/APIs
Scikit-learn, TensorFlow, Apache Lucene, React, Monix
Paradigms
Data Science, REST, Functional Programming, MapReduce
Other
Machine Learning, Data Structures, Statistics, Software Development, Algorithms, Probability Theory, Vowpal Wabbit
Frameworks
Hadoop, Spark, LightGBM, Play, Django, Akka
Tools
Impala, Git, IntelliJ IDEA, PyCharm, Jupyter, Tableau, MATLAB, RabbitMQ
Platforms
Jupyter Notebook, Apache Kafka, Linux, Docker
Storage
Couchbase, NoSQL, Cassandra, Microsoft SQL Server, MySQL
Education
Bachelor's Degree in Applied Mathematics, and Computer Science
National Research University – Higher School of Economics - Moscow, Russia
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