I make and maintain software.
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Josh Duff


I've spent over a decade building desktop and web applications for various industries. I turn customer needs into technical specs and deliver software slowly and steadily over many small iterations/deliverables.

I've delivered software solutions by myself, and as a member of small teams.

I have experience with large web frameworks, but am comfortable building a toolbox out of composable libraries. I have worked with various database systems, but spend the most time with MySQL.

Previous employers

Cake (consumer software), 2016-2017 (remote)

With two other developers, added features and fixed bugs to get the node.js/Express/React app Cake closer to shipping.

eDataSource (email marketing industry), 2013-2016 (remote)

  • With a team of 3-4 developers:
    • Built and maintained a distributed Java application that processes millions of emails per day, indexing the commercial email campaigns and storing the results in MySQL and ElasticSearch
    • Developed a client-facing AngularJS application Email Analyst, used by email marketers to determine the effectiveness of their marketing campaigns and diagnose email deliverability problems
    • Maintained Boxbe, a spam-filtering service used by 1M+ users
  • Built the internal admin site used to manage the domain/brand/company taxonomy, and administrate client user accounts

ISoft Data Systems (car parts and heavy truck parts industries), 2005-2013

In roughly chronological order:

  • Performed maintenance and feature development for an inventory/point of sale application built with C++/MySQL
  • Wrote a minimal CRM tool for internal support use, using PHP and MySQL
  • Wrote an AJAX-based clock-in system with a PHP/MySQL back-end
  • Worked with partner customers to develop an enterprise application, writing specifications and delivering features
  • Developed a push-based replication tool for MySQL databases
  • Became lead developer/designer of legacy Windows application
  • Codified standards for internal documentation in the company wiki, curating and maintaining all input
  • Developed an XMPP chatbot for use in company chat rooms using C++/Gloox
  • Developed an application for performing queries directly against Quickbooks company files
  • Developed a prototype for a PhoneGap-capable mobile version of parts search portal HeavyTruckParts.net with jQuery Mobile, PHP, TinyMVC
  • Developed a web application for enterprise inventory software, for use on mobile hardware with barcode scanners
  • Developed a client framework in JavaScript capable of running in Windows CE's IE6, and Safari Mobile
  • Developed API frameworks for the server-side in both PHP and JavaScript (using node.js)

As the sole phone support tech during my first year at ISoft:

  • Handled all incoming support calls for a Windows-based application
  • Maintained and added to a suite of reports built with Crystal Reports and MySQL queries
  • Travelled to customer locations to perform installations and training
For a long-form description of my time at ISoft, click here.

Open source

Larger projects

An arbitrary selection of my smaller libraries

  • sql-concat, for building SQL statements programmatically
  • financial-arithmeticator, for arbitrary-precision arithmetic on financial values
  • mannish, a mediator focused on reducing coupling between stateful modules in larger apps

For a more complete list of libraries I've published, see tehshrike.github.io.


I have written a few posts related to my software projects:


  • Over a hundred packages published to npm
  • Thousands of lines of code published under an open license (tehshrike.github.io)
  • Retrospectives of projects and explanation for tech problems at joshduff.com

Familiar Technologies

Delivered products/features using:

  • JavaScript
    • node.js
    • AngularJS
    • React
    • Redux
    • Express
    • Koa
  • Java
  • PHP
  • C++
  • MySQL
  • SQLite
  • ElasticSearch
  • Redis

I'm particularly interested in the chance to work with Clojure, Elm, Elixir, or other languages focused on simplicity through pure functions.