Andrew Duffy - Software. Since childhood.

Principal Software Engineer at TripAdvisor



Current location


Work category

IT and Technology



I wrote my first program when I was about ten or eleven - a lotto number picker in GW-BASIC. I started programming for money at fifteen - websites, a Lotus Notes-based work tracking system for a waste company, even a web search engine for the Irish Government's fledgling website, where I was known onsite as "the kid".

Since then, I've worked for and founded several startups. My first full-time job (while still attending university "full-time") was as the first employee of a network management startup, which was later sold. I've since started two of my own - one that does enterprise search and tagging, and one that does network troubleshooting software.

Lately I've been working as a senior or principal engineer in a number of web companies - Amazon, GIlt Groupe and TripAdvisor.

Andrew Duffy's Professional Experience

2014 - Present

TripAdvisor - Principal Software Engineer

TripAdvisor helps people around the world to plan and have the perfect trip.

- Working on the personalisation team on various front- and back-end projects.

Key Skills
Ajax CouchDB Hive Java JavaScript Mootools
2012 - 2014

Gilt Groupe - Senior Software Engineer

Gilt Groupe is a market leading online flash sales site that invites every member to visit at exactly the same time every day, leading to one of the biggest traffic spikes in e-commerce.

- Designed the APIs and lead development of a large project to change how Gilt provisions hardware and deploys software to a new model based on immutability and lightweight containers.
- Regularly took lead in diagnosing and fixing performance- and stability-related issues in production.
- Acted as an internal consultant for architectural- and implementation-related performance engineering.
- Participated in hiring by setting homework challenges, interviewing candidates, and continually improving the hiring and onboarding process.

Key Skills
gatling HTTP Java Jmeter mongoDB Performance rest Scala
2011 - 2012

Amazon - Software Development Engineer (contract)

The hardware load balancers team in Amazon manages the devices which handle virtually all traffic to and from Amazon’s retail sites and S3 along with traffic between internal services.

- Designed and developed a distributed service to provide near-realtime status for every load balanced service instance in Amazon.
- Redesigned and reengineered a complex service for allowing safe deployments that had proven incapable of scaling horizontally at the 50% per year required for an Amazon service. This is used by most teams in the company and has clients installed on tens of thousands of machines.
- Transitioned from an unmanaged development process to an agile process inspired by Kanban cards.

Key Skills
Java Json memcached rest SOAP Spring
2011 - 2011

Data Fusion International - Head of Software Development (contract)

Data Fusion ( was formed to further develop and market software acquired from another company that optimises online research into people’s assets and behaviour by law enforcement or the financial industry.

- Designed and helped implement a series of enhancements to an existing online research workflow system. This uses a web-scraping tool called Denodo to normalise the search experience over multiple hidden-web data sources and creates auditable research files on each target.
- Designed a graphical tool to explore connections between passengers on incoming flights in partnership with ARINC. This was built upon the output of an innovation partnership with the TSSG in Waterford Institute of Technology.
- Maintained and added features to a legacy custom work tracking system implemented in Java, JSP and XSLT.
- Managed a small development team using Scrum, and outsourced development for an EU project.

Key Skills
Agile Balsamiq Mockups Denodo GreenHopper Hibernate IceFaces Java JIRA JSP Oracle scrum Seam Servlets Subversion XSLT
2009 - 2011

DANG Networks - Founder and VP Engineering

DANG Networks ( was founded to develop and sell UltraView, a network management dashboard that uses NetFlow and SNMP and is designed to incorporate other data sources to eventually compete with market leader SolarWinds Orion. The product was launched in May 2010 and has achieved some success in the market.
- Designed the product and managed its development.
- Developed the NetFlow and SNMP data collection and aggregation engine. This presented a significant challenge due to the huge amount of information – NetFlow in particular accounts for every flow of traffic across the router or switch and often amounts to tens or hundreds of gigabytes per day.
- Hired an intern programmer and a junior developer and oversaw development of the front end.
- Handled payroll and HR.
- As company secretary, worked closely with the VP of Business Development to prepare documentation for an external investment.

Key Skills
Ajax Balsamiq Mockups Business Development Cisco IOS css Data Processing ETL Flex Groovy HTML HTTP Java JavaScript JSP MySQL NetFlow Network Management Nullsoft Installer OLAP Prototype Servlets snmp Subversion Trac
2009 - 2009

Private Contract - Software usability consultant

I carried out a detailed usability analysis of NetFlow Auditor from IdeaData Pty. on behalf of Atlantic Business Development Corp., a reseller of the product. Following submission of the analysis most of the highlighted problems were fixed.

Key Skills
NetFlow UI usability
2008 - 2009

Simiolus - Sole founder

I started Simiolus to develop and bring to market Kyral, a knowledge location and sharing tool built on full-text search and collaborative tagging. After the product was successfully deployed with its first trial user I put it on hold to focus on DANG Networks.
- Designed and developed the software; challenges included designing a user interface to express a complex concept to non-technical users, and dealing with the diverse range of unusual document formats found on old corporate networks.
- Contributed bug fixes to the open-source libraries Lucene and PDFBox.
- Carried out all company administration – book-keeping, accounts, payroll, VAT, returns.
- Hired and managed an intern programmer.

Key Skills
Ajax Bookmarklets Cross-browser css derby Groovy HTML HTTP Java JavaScript JSP lucene Nullsoft Installer Office Plugins Prototype Scripting Servlets Subversion Trac Web Application Windows Explorer Plugins
2007 - 2008

Fluke Networks - Senior Software Engineer

Following Crannog Software's acquisition I remained at Fluke Networks for a year where I continued to develop NetFlow Tracker and worked with a team in the USA to integrate it with a new distributed management system.

Key Skills
Cisco Java JSP MySQL NetFlow OLAP snmp
1998 - 2007

Crannog Software - Chief Technical Architect

Crannog Software was formed in 1998 to develop and market innovative network management software in competition with several huge market leaders. I was the first employee and later became a shareholder. The company was acquired in early 2007 by Visual Networks ( which still markets NetFlow Tracker.
- Designed and solely developed NetFlow Tracker, a system for analysing network traffic by receiving and processing NetFlow and sFlow information generated by routers and layer 3 switches. The release of NetFlow Tracker in 2004 marked a turning point in the company’s development, allowing revenues to double year-on-year for the three years to 2006, when the company came 13th in the Deloitte Technology Fast 50. At acquisition over 70% of the company’s turnover was comprised of sales of NetFlow Tracker.
- Designed the management portal OneView; ResponseWatch, a simulated response time management tool that uses Cisco's IPSLA; and PFR Manager, a tool developed in partnership with Cisco to manage a new performance-based dynamic routing technology.
- Designed and developed the network management server for NetWatch and a generic reporting system for ISDNwatch, both earlier products in the company’s portfolio.

Key Skills
Ajax Applets C++ Cisco css ETL HTML HTTP Java JavaScript JSP Linux mfc MySQL NetFlow Network Management OLAP Servlets sFlow snmp Solaris Windows Installer
1995 - 2003

Dublin Waste - Custom software developer (contract)

Dublin Waste was a waste removal and processing company based in Dublin that was acquired by Greenstar in 2003.
- Developed and maintained an order tracking and work assignment system for Dublin Waste, written in Lotus Notes to take advantage of its built-in replication. Switching from paper to an electronic work tracking system allowed the company to grow its turnover from under £1m to over €5m.

Key Skills
Lotus Notes
1998 - 2000

CMOD - Custom software developer (contract)

CMOD ( is the Irish government’s central IT service.
- Developed and maintained a web search engine that was available on the government’s web site for over two years. The system was written in Java and used modest hardware to index and search about one gigabyte of text.

Key Skills

Andrew Duffy's Education and Qualifications


Bachelor/Degree - Computer Applications


Andrew Duffy's Additional Information




Good espresso, good food, working out to keep in shape after too much good food.