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David Pfeffer

David Pfeffer

Annandale, NJ, United States
Member since May 6, 2016
David is a software engineer and an adjunct computer science professor at Stevens Institute of Technology in Hoboken, NJ. He’s been involved in a number of startup businesses as well as worked in the financial services sector on high bandwidth/high transaction computing. He’s an expert in C#/.NET and TypeScript, having used both since initial betas, and he does regular work with .NET Core and Node as well as React, Angular, Cordova, and Ionic.
David is now available for hire
Portfolio
Experience
  • C#, 17 years
  • .NET, 17 years
  • Microsoft SQL Server, 10 years
  • ASP.NET MVC, 6 years
  • MongoDB, 6 years
  • TypeScript, 5 years
  • React, 3 years
  • Angular, 3 years
Annandale, NJ, United States
Availability
Part-time
Preferred Environment
Git, Visual Studio Code, C#, TypeScript
The most amazing...
...project I've helped build is a real-time trading exchange with a true stock order book for trading shares in teams during sporting events.
Employment
  • CTO
    2016 - PRESENT
    BallStreet Trading
    • Developed a greenfield mobile app in Ionic2.
    • Guided a UX consulting team to produce beautiful designs for our platform.
    • Managed several part-time developers.
    • Built a real-time trading engine to power our system, with a true stock market style order book, and near-instantaneous settlement of trades.
    • Helped pitch to a multitude of investors to raise capital for the company.
    Technologies: TypeScript, MongoDB, JavaScript, HTML5, Ionic2, Angular2, CSS, ASP.NET Web API, .NET Core
  • Adjunct Professor
    2011 - PRESENT
    Stevens Institute of Technology
    • Taught introductory programming.
    • Taught advanced systems programming for Unix environments.
    • Taught advanced network stack code, including a reimplementation of the TCP/IP networking stack.
    • Managed graduate students who wanted to pursue independent study.
    Technologies: C++, JavaScript, TypeScript, C
  • CTO
    2012 - 2016
    FunnelFire
    • Built a real-time sales intelligence engine from the ground up.
    • Wrote sophisticated back-end code that crawled various APIs such as Facebook and Twitter as well as scraping various internet pages to build rich profiles on companies.
    • Built a real-time front-end that integrated with the back-end using SignalR/WebSockets to update company profiles on the user's screen as soon as new information was available.
    • Fetched news from a variety of sources, such as Facebook feeds, RSS, and a news API, and stored it in ElasticSearch before generating feeds that were relevant to company profiles.
    • Managed and mentored several developers.
    Technologies: C#, TypeScript, MongoDB, ElasticSearch, RavenDB, RabbitMQ, Facebook, Twitter, LinkedIn, ASP.NET MVC, SignalR, Web Sockets, Angular, Ionic, SendGrid, Email
  • CTO
    2010 - 2014
    FivePM Technology
    • Developed a real-time vehicle tracking and dispatch system.
    • Worked with Windows Azure cloud technology to use as back-end infrastructure in order to ensure the fulfillment of service level agreements.
    • Used enterprise service bus middleware technology to handle all requests by users or vehicles.
    • Developed hardware and software for a Linux-based embedded computer platform to put onto vehicles to report vehicle location, handle fare collection, and deliver information needed by passengers or operators.
    • Managed interns responsible for large projects such as a system-wide administrative console intuitive for city administrators.
    • Interfaced with the cell phone text message system to develop a short-code SMS mechanism for locating buses.
    • After a senior citizen user study, built a call-in system that used text-to-speech to read the vehicle location and ETA.
    • Developed apps for iOS, Android, and Windows Phone 7 by leveraging the MonoTouch and Mono for Android SDKs (Now Xamarin).
    Technologies: C#, .NET, ASP.NET MVC, SignalR, TypeScript, JavaScript, RavenDB, SQL Server, RabbitMQ, Ubuntu, Linux, Gentoo, Embedded Linux, Twilio, SMS
  • Software Developer/Analyst
    2009 - 2012
    Deutsche Bank
    • Developed a real-time log file analysis engine for legacy bank applications.
    • Created automated testing framework for trades processing loader, facilitating an upgrade to Geneva 7.6.
    • Developed “high-bandwidth” framework in C# in parallel to and compatible with a Java framework, avoiding garbage collection and other activities that could cause a performance lag.
    • Implemented and managed a collaborative development environment, bringing teammates from Bangalore, the United Kingdom, and the United States together on one platform. Developed business processes for use of environment.
    • Created a scheduler system allowing business users unfamiliar with IT to schedule complex jobs.
    • Created a wrapper around a buggy vendor tool to avoid a $15,000 redevelopment task by the vendor.
    Technologies: Geneva, C#, .NET, Java, Prism, MVVM
  • IT Integrations Consultant
    2008 - 2009
    World Travel Group
    • Planned, tested, and integrated a full overhaul of IT solutions, replacing a dozen legacy servers with a virtualization platform.
    • Successfully outsourced email to Microsoft Hosted Services on an Exchange platform after a test period involving both Google Mail and Microsoft Exchange.
    Technologies: SMTP, Postfix, Google Apps, Windows Server, HyperV, VMWare, Microsoft Exchange
Experience
  • BallStreet App (Development)
    https://play.google.com/store/apps/details?id=com.ballstreettrading

    Using Cordova, React, and Onsen UI, I built a trading app for simulated "stocks" representing a team winning a sporting event. Real-time market information is transmitted via web sockets from the back-end, and graphs/charting is done with the D3 library. An iOS and Android version of the app is now released.

  • BallStreet Proof-of-Concept App (Development)
    https://play.google.com/store/apps/details?id=com.ballstreettrading

    Using Ionic and then Ionic2, I built a trading app for simulated "stocks" in the outcome of a team winning a sporting event. Real-time market information is transmitted via web sockets from the back-end, and graphs/charting is done with the D3 library. We did a MVP release in Ionic, and then ported to Ionic2. We were ultimately forced to move off of Ionic2 because the platform was not released by the time we were nearing our debut, but the port was very easy to accomplish and the platform worked very well.

  • FunnelFire Back-end Engine and Architecture (Development)

    I built a real-time sales intelligence tool for researching information and the latest news about companies while at FunnelFire. It is intended to be used for pre-call research as well as to stay up-to-date on a company's behavior.

    The engine was built in C# on a service bus architecture, with a series of ingestors running to pull data from a variety of data sources (Facebook API, Twitter API, CrunchBase, Lexis Nexis, Freebase, AngelList, web crawling, etc) in response to messages and then to publish results as they were found back onto the bus. A company comparison algorithm then compares the company profiles found, and, depending on match confidence, either merges the results into an existing company, creates a new company, or creates a potential merge for human verification via the Amazon Mechanical Turk. News stories are fed through the same bus when discovered, where they land on an ElasticSearch database for future querying. A trie of all company names is stored in a proprietary self-designed database system, rapidly matching company names found in the article to help start off various push notifications and email alerts.

  • Teaching Computer Science at Stevens Institute of Technology (Other amazing things)
    http://web.stevens.edu/facultyprofile/?id=1692

    I'm teaching a variety of courses to undergrads and grad students at Stevens Institute, such as advanced data structures and algorithms, introductory Computer Science, Linux systems programming, low-level TCP/IP networking, a crash course in "Advanced JAVA for C++ Developers," and software engineering topics such as QA.

  • FunnelFire App (Development)

    I built an Ionic (AngularJS) app during my time at FunnelFire. The app does not show off my ability to create beautiful apps--the app looks fairly kludgey--but rather my ability to rapidly iterate under strict time constraints. The app was built in less than a week in order to appease various sales managers who would not buy our product without there being a mobile app presence. Much of the code is shared with the front-end web application, since they're both built in AngularJS, which improved long-term maintainability.

  • MedChat (Development)
    https://www.medchatapp.com/

    I built the chat widget for MedChat, an Olark-like real time chat engine with medical compliance.

  • Real-time Vehicle Tracking System ("Treadmarks") (Development)

    While at FivePM Technology, I built a real-time vehicle tracking system for shuttle buses. The vehicles carried an onboard embedded Linux platform that I developed and maintained, a cellular modem, and communicated via a special low-byte count protocol I developed to transmit vehicle position to a server I wrote that sat on Azure. We then took those positions to calculate ETA to bus stops, and responded to requests via text message and phone calls via Twilio to report the ETA to a stop or the current shuttle locations. We also delivered the location of the vehicles on a live map online, using web sockets to update the vehicle positions and interpolating between data pushes.

    The entire platform was built on .NET, with Mono running on the buses and various workers written in C# and ASP.NET with SignalR powering the back-end and web app.

  • Taxi Hailing System (Development)
    http://www.hudsonreporter.com/view/full_story/12587964/article---Hoboken-launches-new-virtual-taxi-hailing-system

    I developed a primitive version of an "Uber" for the Hoboken, NJ taxi system. Hoboken's taxi drivers did not have smartphones and were reluctant to have a GPS device onboard due to "big brother" concerns. However, Hoboken is also only a square mile in area. Text message based hails indicating where a rider was located would trigger a message to be sent out to the highest rated drivers that had sent a text-based command into the system reporting that they were "online." One of those drivers could reply reporting that they are going to accept the ride. If they were the first to reply and the request hadn't timed out, they would be texted back with the location of the rider and the rider would receive a confirmation text. We then also used Twilio to allow the driver and rider to communicate via phone or text without releasing either of their phone numbers to one another. At the end of the ride, passengers were asked to rate their driver from 1 to 5, and low-rated drivers were deprioritized in the system for receiving text hails.

    The platform was built in C# with heavy utilization of Twilio. Ultimately, Uber of course took off and Hoboken gave up trying to control the internet-based hailing of their taxis.

  • StackOverflow Top 2% Overall Ranking (Other amazing things)
    http://stackoverflow.com/users/172029/david-pfeffer

    I am in the top 2% of overall user reputation on StackOverflow.

  • Guest Instructor at Webb Institute (Other amazing things)

    I taught a special topics course at Webb Institute, the renowned ocean/naval engineering school on Long Island, NY. The school did not have anyone capable of teaching a complex programming course, so I was brought in to instruct the students in a crash-course in programming coupled with data structures and algorithms over the course of a semester.

Skills
  • Languages
    C#, TypeScript 2, TypeScript, JavaScript, CSS, HTML5, HTML, SQL, CSS3, Java, F#, VB.NET
  • Frameworks
    .NET, Angular, Ionic 2, Cordova, Redux, Onsen UI, Ionic 3, .NET Core, ASP.NET MVC, AngularJS, Ionic, Express.js, Electron.js, React Native
  • Libraries/APIs
    React, React Redux, Flexbox, Facebook API, Google Maps API, Twitter API
  • Paradigms
    Concurrent Programming, Spatial Databases, MapReduce
  • Platforms
    Azure, Android, iOS, Amazon Web Services (AWS), Visual Studio Code, Docker, Embedded Linux
  • Storage
    MongoDB, RavenDB, Microsoft SQL Server, Elasticsearch, Couchbase
  • Other
    Distributed Systems, Software Architecture, Industrial IoT, TCP/IP, Bluetooth LE (GATT format)
  • Tools
    Adobe Photoshop
Education
  • Master of Science degree in Computer Science
    2007 - 2009
    Stevens Institute of Technology - Hoboken, NJ
  • Bachelor of Science degree in Computer Science
    2005 - 2009
    Stevens Institute of Technology - Hoboken, NJ
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