Denys Sinyakov, Developer in San Francisco, CA, United States
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Denys Sinyakov

Verified Expert  in Engineering

Algorithmic Trading Developer

San Francisco, CA, United States
Toptal Member Since
April 28, 2015

Denys is a seasoned software engineer, engineering manager, and entrepreneur with over 11 years of experience. He specializes in distributed and scalable web applications targeted to run in the cloud. Has a track record of using diverse programming languages and technologies with Java being a favorite one. Since the start of his career, he has been an advocate for readable, maintainable, and testable code.


Cisco Systems
Amazon Web Services (AWS), OpenStack, AMQP, MongoDB, Mesos, Apache Avro...
Max2 (via Toptal)
MySQL, Redis, Akka, Play Framework, Scala, Apache Kafka, Java
Amazon Web Services (AWS), VMware, CSS, HTML, Akka, ZeroMQ, Apache Thrift...




Preferred Environment

Amazon Web Services (AWS), Docker, Linux, MacOS, Git, IntelliJ IDEA

The most amazing...

...thing I've coded was a MapReduce that could process and modify the data of more than a billion records in less than 10 minutes.

Work Experience

Senior Software Engineer

2015 - PRESENT
Cisco Systems
  • Built an API gateway and data processing/aggregation microservices using Springboot for a distributed monitoring solution.
  • Made key contributions to the design and implementation of a Java auth framework based on Oauth2.
  • Implemented a project management system on top of Openstack API.
  • Increased stability and security of an open sourced monitoring Ruby-based agent by refactoring and implementing the authentication layer.
  • Boosted performance of the data ingestion service by 60% by analyzing code with profiling tools and fixing identified issues (decreased auth overhead, optimized payload processing).
  • Implemented product licensing capabilities in monitoring solution by building middle-tier services and integrating with licensing service.
Technologies: Amazon Web Services (AWS), OpenStack, AMQP, MongoDB, Mesos, Apache Avro, PostgreSQL, Redis, Elasticsearch, Apache Kafka, Docker, Jersey, Ruby, Spring, Python, Go, JavaScript, Java

Java Developer

2015 - 2016
Max2 (via Toptal)
  • Hardened mobile app Java back-end API security by introducing a signed request feature (Amazon API like).
  • Boosted performance of API back-end pagination requests by 50% by implementing Redis-based pagination.
  • Increased the robustness of the API by introducing JSON schema and automated payload field validations.
  • Made code more reliable and testable by refactoring and applying testability best practices.
Technologies: MySQL, Redis, Akka, Play Framework, Scala, Apache Kafka, Java

Founder and Lead Developer

2014 - 2015
  • Designed and implemented a VPS infrastructure orchestration layer in Python.
  • Built a cloud provisioning system based on a custom work queue implemented with Java and
  • Designed and implemented a cloud control panel with PHP and AngularJS.
  • Built integration with Amazon AWS via Java API.
  • Created the main company website.
Technologies: Amazon Web Services (AWS), VMware, CSS, HTML, Akka, ZeroMQ, Apache Thrift, Play Framework, AngularJS, Python, PHP, Java

Engineering Manager

2012 - 2014
Google (via EPAM)
  • Implemented a number of BI system plug­ins for proprietary file systems, databases, and data warehouses.
  • Designed and implemented a web application that served as a meta­data dictionary for the data delivered to multiple data warehouses.
Technologies: Protocol Buffers, CSS, HTML, GWT, AngularJS, JavaScript, Java

Software Engineer

2011 - 2012
Google (via EPAM)
  • Developed a multi-­purpose Java query tool based on MapReduce.
  • Participated in the migration of the application from a MySQL to a NoSQL database.
Technologies: JavaScript, Python, Java

Software Engineer

2010 - 2011
Google (via EPAM)
  • Implemented a GWT front­-end framework that served as the basis for application development for a CRM administration application.
  • Implemented a quick search feature that improved the UX.
  • Re­-engineered the application's mail queue administration view.
  • Covered the application functionality with functional automated tests.
Technologies: NoSQL, MySQL, MapReduce, Protocol Buffers, Python, GWT, Java

Software Test Engineer

2006 - 2010
  • Developed a testing framework in Java/Selenium for a web application.
  • Created a number of JavaScript extensions for the Java/Selenium testing framework.
  • Wrote a parser in Perl that helped to fix thousands of legacy automated tests written in Tcl.
Technologies: Selenium, WebDriver, JavaScript, Perl, Python, Java

Java Quant/algorithmic Trading Framework

The framework is implemented based on Interactive Brokers Java API and open sourced back-testing engine. Allows to easily implement new trading strategies and backtest them, using historical data from multiple sources: Interactive Brokers API, Yahoo Finance API, Database, CSV files.


A web application that allows for sharing of photo albums across multiple social networks. Technologies used include Facebook API, Instagram API, VK API, AngularJS, Redis, and Play!


Developed a PaaS for PHP, RoR, Python, and Java app deployment. Technologies used include Go!, Ruby on Rails, MongoDB, and Docker.


Java, Perl, HTML, CSS, Ruby, Scala, Python, Go, CSS3, PHP, JavaScript, HTML5, SQL


Spring, Play Framework, AngularJS, Selenium, GWT, Akka, Jersey, Bootstrap 3, Apache Thrift, Django


Interactive Brokers API, WebDriver, AMQP, ZeroMQ, Instagram API, Facebook API, jQuery


Amazon Elastic Container Service (Amazon ECS), Apache Avro, Mesos, Amazon Virtual Private Cloud (VPC), IntelliJ IDEA, Git, VirtualBox, VMware, Vagrant


Docker, Linux, Amazon Web Services (AWS), Apache Kafka, OpenStack, AWS Lambda, Amazon EC2, FreeBSD, MacOS


Algorithmic Trading, Quantitative Finance, Natural Language Processing (NLP), Protocol Buffers, GPT, Generative Pre-trained Transformers (GPT)


Agile Software Development, MapReduce


Elasticsearch, NoSQL, MongoDB, MySQL, H2, PostgreSQL, Redis

1999 - 2004

Master of Science Degree in Radio Electronics Engineering

Khmelnitsky National University - Ukraine

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