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Sean Sawyer

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Education

BS in Computer Science, December 2002, University of Georgia

Qualifications

I love to build data-heavy applications, most often using Python, Java and sometimes Scala. Under the hood of the things I’ve built in recent memory you’ll also find Elasticsearch, Kafka, PostgreSQL, and Redis.

In the past, I’ve built distributed systems with Erlang and web applications with PHP and Ruby.

Although it hasn’t been my primary focus, I’ve also done a decent amount of devops along the way - on bare metal, managed hosting, AWS and GCP - and have worked with both Puppet and Chef.

Professional Experience

Senior Software Engineer at MailChimp

May 2012 to present

Throughout my time at MailChimp, my efforts have focused on turning our data scientists’ research into production services that empower small organizations and businesses by putting the power of analytics and statistical modeling within their reach.

  • Designing and leading development of MailChimp’s data pipeline, which streams billions of row-level changes each day from the binlogs of our hundreds of MySQL instances. The underlying triptych of Scala applications produces Kafka topics representing each change as a Thrift-serialized struct.
  • Creating and maintaining client libraries and tooling related to MailChimp’s data pipeline, variously in Java, PHP and Python.
  • Designing and building MailChimp Pro’s reporting and segmentation service using Scala, PHP, PostgreSQL and Redis.
  • Designing and building MailChimp’s predictive analytics service using Python, R, Redis and RabbitMQ. The service maintains summary statistics on around 4 billion unique email addresses, which feed models for predicting bounce rates, optimizing campaign send times, and detecting bots.
  • Prototyping MailChimp’s predictive demographics service, as well as a BI tool enabling customers to perform ad hoc analysis on their MailChimp data using Python and BigQuery.
  • Contributing to the development of MailChimp’s in-house web framework, including improvements to its ORM, process management, and concurrency APIs.
  • Collaborating across a wide array of teams to facilitate access to data for stream and batch processing.

Staff Engineer at Vitrue

July 2010 to May 2012

As a lead developer on Vitrue’s Core Services team, I focused heavily on modularizing and scaling the core APIs behind Vitrue’s social marketing platform.

  • Developed a social data harvesting/notification service and caching API using Erlang, ZeroMQ, Redis and PostgreSQL. This distributed system replaced a slower, more limited Ruby application, realizing substantial performance and reliability gains.
  • Led development of Vitrue Publisher’s conversational features for Facebook and Twitter using Ruby, Rails and MongoDB.
  • Prototyped Vitrue’s location-based marketing offering: a self-service toolkit with Foursquare and Facebook Places integration, also built using Ruby, Rails and MongoDB.
  • Collaborated with other members of the team on devops-focused efforts, building and maintaining Vitrue’s EC2 infrastructure using Chef and Scalr.
  • Mentored junior engineers via frequent pair-programming and code review sessions, as well as organizing reading groups.

Senior Software Engineer at Mobilization Labs

May 2008 to July 2010

At Mobilization Labs, I helped drive development of Wildfire Platform, a SaaS web application used by primary by non-profits to manage and mobilize their supporters for grassroots action. The application was used by a diverse crowd of organizations, from the National Urban League, to the Atlanta Mission, to even the Jonas Brothers. Wildfire was built using Java, Spring and PostgreSQL.

  • Led development of the platform’s REST API and implemented a number of client applications powered by the API, including a live SMS survey application written in Scala, and a number of smaller-scale PHP solutions.
  • Created and maintainted a load testing suite (using Tsung) simulating common traffic patterns within the application based on analysis of access logs from periods of heavy production load.
  • Collaborated with other engineers in scaling the platform, including the integration of Terracotta for clustered heap and S3/Cloudfront for asset delivery.

Senior Software Engineer at InComm

January 2008 to May 2008

I helped guide the growth of InComm’s web development team by by agitating for improved development practices, mentoring other developers, and leading a range of improvements across the gaggle of web applications owned by this small team.

  • Designed and implemented a half-dozen new web applications (some internal, some user-facing) using Java and Spring, while supervising a team of five engineers. I also designed the UI for several of these applications, for better or for worse!
  • Planned and implemented a number of much-needed improvements to existing production applications on a variety of platforms (Ruby/Rails, Java/Spring, ColdFusion). These included UI overhauls, performance optimization and critical feature additions, as well as migration from Struts to Spring MVC.

Odds and Ends

During my time at Vitrue, my employer was kind enough to let me open-source an Erlang ISO 8601 library.

Long long ago, I worked as a Java developer at Hannon Hill and as a sysadmin and PHP developer at a small law firm.