As an engineer, led the creation of a number of prominent product features. Led a team responsible for Mailchimp's audience storage infrastructure which houses the records for many billions of subscribers. Maintained and, at times, rescued the systems that record clicks and opens for all email campaigns. Wrote or maintained many core libraries and systems that were used across all of engineering, including the feature flagging system, libraries for configurable retry and internal rate limiting, the distributed tracing system, various internal operational tools, and Mailchimp's internal PHP & Go application framework.

As an engineering leader, helped shape the overall technical direction adopted by all engineering teams and helped to shape the broader engineering culture. This included a push to begin building towards a service oriented architecture even while the majority of engineering work continued within a monolith. Provided guidance to nearly every team at Mailchimp at some point. Worked directly with the CTO to help shape technical direction and also directly with engineering teams to try to apply that direction to real problems and projects. Was instrumental in the adoption of a continuous deployment model where we went from shipping a release every 2 weeks to one where we ship nearly 200 changes daily. In general, tried every day to make Mailchimp engineering better than it was the day before.

Senior member of Etsy's Search Experience team, responsible for buyer search, discovery and exploration in all of Etsy's platforms. Led the creation of Etsy's updated exploratory search experience. Wrote and maintained a new version of product search in the Etsy Anddroid App. Along with a small group of senior engineers, established Etsy's Architectural Review Groups which was responsible shaping Etsy's technical infrastructure through a healthy mix of concensus building and guidance. Heavily focused on scaling a healthy engineering culture. Wrote and released as open source the Hound Code Search Engine which was used extensively within engineering.

Co-founded with Joel Webber, Bruce Johsnon, and Scott Voigt; Fullstory is a pioneer in the Digital Experience space. Involved at the very beginning of the product taking it from unproven product hypothesis to prototype and then to minimum viable product. Proud to have introduced some names and concepts that are still very much pressent in the product, including Rage Clicks and the name Fullstory. Released a couple of open source tools including Underpants, an oauth2 reverse proxy for protecting admin interfaces in cloud environments, and pork, some web tooling used by Fullstory engineering for many years.

Work was primarily focused on web browsers, building complex web applications and developer tools for expanding what was possible in web browers at the time. Served a number of roles including individual contributor, engineering manger and tech lead. Worked on a number of recognizeable products in some form or another, including Google Web Toolkit (2006–2010), Speed Tracer (2008–2010), AdWords (2009), Google Wave (2009–2010), Dart (2011), WebKit (2009–2012), Google Chrome (2012). Won an OC award (the 2nd highest award for innovation at Google) in 2009 for web performance work on AdWords.

Became a committer in 2009. Built the first version of the renderer performace tracing that first appeared in the Timeline view of Chrome's Developer Tools. Later established a team in Atlanta to maintain WebKit's SVG implementation.

Led a small team with the goal of bringing a new set of low-level primitives to the web platform. Involved in the very early stages of the “dart platform” and worked on a variety of projects to support its initial public launch. The most visible of which was https://try.dartlang.org which made it possible to try the language and libraries in a browser.

Led the creation of Speed Tracer, a Chrome extension that exposed deep performance insights from tracing data in WebKit. Took the idea from a 20% project that worked on both Chrome and IE7 and ultimately shipped the public version as a Chrome extension that was part of the Google Web Toolkit. Led the small team responsible for Speed Tracer which was widely regarded as a highly impactful team. Three years after active development had ceased, Speed Tracer still maintained hundreds of thousands of 7 day actives.

Worked on pretty much every part of the product at some point. Very early member of the GWT team and served as Tech Lead on more than one occassion. Contributions include the first debugger (“Hosted Mode”) for Mac, the plugin-based degugger (”Dev Mode”), and the low-level Elemental library to name a few. “Embedded” with a number of major projects at Google using GWT, including AdWords and Wave. In 2010, he won an OC Award (the second highest award for innovation at Google) for his performance work with AdWords. Spoke on multiple occassions at Google IO and other technical conferences representing Google.

Spant a summer working with IBM's Advanced Internet Technology Group on some special projects ranging from semantic web to data visualization.

Member of John Maeda's Physical Language Workshop research group. Research work spanned collaborative creative tools, digital art and online digital art markets that maintained chains of provenance. The group's work with OpenStudio seems remarkably prescient given the recent popularity of NFT art markets. Significant contributions to all the group's projects, including Open Studio. Thesis explored a system for expanding visual designs to screens of all sizes, aspect ratios and color depths by leveraging both computer automation and human experts. The work pre-dated the proliferation of screens that became a part of every day life with the releases of the iPhone and the Android operating system.

Co-founded with Shawn Coyne and Peter Flur. Connexxia's primary product, AdmissionsGenie, helped colleges and universities more effectively recruit students by connecting them to real people through the web. It showed consistent results improving yield for college admissions and hosted the admissions sites for a number of schools, including some big names like Duke University, Emory University and Georgia Tech. Connexxia was acquired by Internet marketing firm James Tower. Later, James Tower decided to focus the entire company on the higher education market and rebranded themselves Blue Hue Education. In 2013, AdmissionsGenie was still the name of their premier product. Kelly was actually targeted by his own recruiting tool when he neared graduation at MIT.