Dan Napierski, Developer in Boston, MA, United States
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Dan Napierski

Verified Expert  in Engineering

Software Developer

Boston, MA, United States
Toptal Member Since
April 28, 2016

Dan is a software architect and technology professional focusing on applications of blockchain technologies. He has years of experience providing professional consulting services to clients ranging from startups to global corporations. He specializes in bringing rigorous testing and bulletproof code to tough engineering challenges. He has deep expertise in many aspects of artificial intelligence, blockchain, machine learning, and automation.


Napierski Consulting
Stellar SDK, Ethereum, Litecoin, Bitcoin, Blockchain
Phfeast, Inc.
OAuth, Azure SQL, Microsoft SQL Server, Entity Framework, Swift, .NET...
PolyRemedy, Inc.
Mobile, Android, Microsoft SQL Server, Web Services, C#, .NET




Preferred Environment

Xcode, Git, Python, Node.js, Atom

The most amazing...

...thing I've coded was able to process legal contracts to determine key dates and amounts specified within.

Work Experience


2014 - PRESENT
Napierski Consulting
  • Developed and deployed Solidity contracts on Ethereum blockchain using Truffle as well as a custom Node.js React front end. Executed RPC commands using Web3.js to publish and execute contracts on test and main networks.
  • Architected the payment and collateral system on Stellar blockchain. Developed a fork of Stellar core in C++ to support custom ledger features.
  • Created an alt-coin, forked from Litecoin, capable of storing and querying text records on the blockchain.
  • Developed signal and trading bots using cryptocurrency exchange APIs in Node.js.
  • Administered full Ethereum, BTC, and LTC nodes in a local development environment and in virtual infrastructure using Ansible, Terraform, and Docker.
  • Audited a complex Node.js React/Redux web application to identify security concerns and performance issues. Recommended steps to automate deployments in Azure and manage pull requests in Git.
  • Led the development of several models using AWS SageMaker, Python, and Mathematica. Each accurately predicted home listing prices in a large metropolitan area using MLS listings in a supervised learning environment.
  • Created a chatbot using IBM’s Watson that processed legal contracts to determine effective dates and critical clauses contained within.
Technologies: Stellar SDK, Ethereum, Litecoin, Bitcoin, Blockchain


2014 - 2016
Phfeast, Inc.
  • Founded Phfeast, Inc., as a software company engaged with social issues. Developed a loyalty program that provided free restaurant meals to families in need.
  • Created a suite of secure, high-performance, RESTful web services in .NET responsible for fully supporting both a popular AngularJS web app and mobile app prototype.
  • Developed an automated email alert subscription service and profile management system, regularly sending thousands of custom messages per day.
  • Performed a web application performance audit and analysis that led to significant page load time improvements.
  • Implemented automated functional tests, load tests, and executive reports, employing .NET tools, SQL Server Reporting Services, and Lua web API scripts.
  • Integrated Google maps, Amazon Web Services, OAuth providers, and social media plugins within a responsive web offering.
  • Implemented SEO pre-rendering techniques to support proper indexation of AngularJS pages by internet search engines.
Technologies: OAuth, Azure SQL, Microsoft SQL Server, Entity Framework, Swift, .NET, RESTful Web Services

Director of Software Engineering

2012 - 2013
PolyRemedy, Inc.
  • Delivered a complete Android smartphone app, a RESTful web service API, and a dynamic HTML5 user interface within a 12-month timeframe.
  • Produced a first-in-class web service platform for in-home patient assessment and therapeutic fulfillment by healthcare professionals.
  • Drove the transformation of an existing engineering group into a high performing team through the implementation of Agile methods, code reviews, and automated testing.
  • Managed the engineering department budget, staffing, and multiple product schedules throughout the development lifecycle.
  • Worked closely with heads of marketing, clinical research, and operations to coordinate product deliveries.
  • Analyzed camera sensor data from multiple smartphone models.
  • Incorporated event-driven text messaging into our mobile app.
Technologies: Mobile, Android, Microsoft SQL Server, Web Services, C#, .NET

Software Engineering Team Lead

2011 - 2012
PolyRemedy, Inc.
  • Led a distributed team of engineers, designers, and quality assurance professionals in releasing an innovative software product for home health aides and visiting nurses.
  • Turned diverse user needs and stakeholder desires into achievable milestones, resulting in on-time and well-tested product delivery.
  • Managed web application availability and medical product fulfillment operations.
  • Served as software architect, DevOps manager, and security chief.
  • Produced a scalable SQL Server database design and Entity Framework mapping for efficient querying and retrieval by .NET web services and automated services.
Technologies: JavaScript, HTML, Microsoft SQL Server, Web Services, C#, .NET

Principal Software Engineer

2009 - 2011
Unidesk Corporation
  • Integrated LDAP user accounts, VMware vSphere and View resources, and external APIs to create a broad set of secure .NET web services to manage virtual machines and application deployment.
  • Integrated ActiveMQ messaging and inter-process communication using .NET remoting for a scalable, distributed architecture.
  • Redesigned critical business applications to improve performance, reliability, and maintainability.
  • Served as Scrum master to a cross-functional team of six developers working on a range of product features.
  • Automated testing and deployment in both Microsoft .NET IIS and Linux Apache Mono environments using Python, NUnit, NCover, and Bamboo.
Technologies: JavaScript, VMware vSphere, LDAP, ASP.NET, Python, Microsoft SQL Server, Web Services, C#, .NET

Founder and Chief Architect

2006 - 2009
Napierski Consulting
  • Directed software development within a client team during development of a large-scale data-driven web application offering custom financial reports.
  • Redesigned a client data model using SQL Server and NHibernate to facilitate efficient database querying.
  • Advised large and medium sized clients in the adoption of Agile development methods.
  • Completed evaluations of internet technologies for clients to improve website performance, security, and usability.
  • Developed custom software testing tools for Mathematica.
Technologies: Mathematica, JavaScript, Java, NHibernate, Microsoft SQL Server, ASP.NET, .NET, C#

Senior Software Engineer

2004 - 2006
Arts Alliance Labs, Inc.
  • Developed a recommendation server for a large DVD rental company based upon collaborative filtering technology.
  • Designed and implemented the membership and administration systems for multiple websites in a widespread European digital cinema initiative.
  • Drove the adoption of a number of best practices including test driven development.
  • Set up a continuous integration server to automate builds and deployments.
  • Created a tiered architecture for a high-performance web application.
Technologies: NUnit, Microsoft SQL Server, XML, HTML, .NET, ASP.NET, C#

Software Engineer and Scientist

2001 - 2004
Charles River Analytics, Inc.
  • Redesigned an advanced human behavior representation (HBR) based upon the recognition-primed decision (RPD) model for a government research project.
  • Developed a component-based architecture that allowed users to construct a wide variety of autonomous intelligent agents.
  • Organized communication between the development team and the government sponsor.
  • Co-authored and presented a research paper on the project at the Conference on Behavior Representation in Modeling and Simulation.
  • Implemented Bayesian network, fuzzy logic, and expert system technologies integrated within a Department of Defense simulation.
Technologies: Python, JavaScript, MATLAB, Java
2016 - 2016

Certificate Backed By MIT in Fintech: Future Commerce

GetSmarter - Online

2000 - 2001

Master of Science Degree in Computer Science

Harvard University - Cambridge, MA

1994 - 1998

Bachelor of Science Degree in Economics

Duke University - Durham, NC


API Development, Web3.js, Node.js, Google API, Amazon API, Google Maps, D3.js, Entity Framework, React, Twilio API, jQuery, Facebook API


Mathematica, Microsoft Visual Studio, Ninject, Xcode, Git, Microsoft Team Foundation Server, Atom, VMware vSphere, Stellar SDK, Eclipse IDE, MATLAB


.NET, Flutter, NUnit, NHibernate, Entity, ASP.NET, ASP.NET MVC 5, ASP.NET Web API, ASP.NET MVC, AngularJS, Bootstrap


Agile Software Development, Continuous Integration (CI), DevOps, Cross-platform, Concurrent Programming, Object-oriented Design (OOD), Test-driven Development (TDD), Design Patterns


C#, PHP, Solidity, Python, Java, Swift, C++, SQL, JavaScript, XML, HTML, Haskell, Lua


Blockchain, Windows, Ethereum, iOS, Android, Azure, Mobile, Linux


Microsoft SQL Server, Azure SQL, MySQL

Industry Expertise

Banking & Finance


Bitcoind, Fintech, Cryptocurrency, Machine Learning, RESTful Web Services, Artificial Intelligence (AI), Web App Development, Mobile App Development, API Design, DApps, Software Development, ÐApp, Blockchain Development, Front-end Development, IBM Watson Analytics, Mobile Wallet, Bitcoin, SSL Certificates, Cryptography, Agile Software Testing, Video Streaming, Computer Graphics, Natural Language Processing (NLP), Computer Vision, Location Services, Network Programming, Optimization, Virtualization, Bayesian Statistics, Generative Pre-trained Transformers (GPT), OAuth, Web Services, LDAP, Litecoin

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