Li Haoyi



San Francisco, CA / Singapore

Staff Software Engineer, Tech Lead - Developer Experience

Oct 2017 - Present
  • Managed a distributed team of 6 across 5 countries in 3 timezones, onboarding 5 new engineers of varying seniority and teaching them everything necessary to be productive and effective at Databricks
  • Led the Devtools prioritization process: surveying engineers on their pain points, aggregating feedback, and planning projects to improve things. Increased the average self-reported happiness score from 3.1 to 3.8/5.0
  • Ran weekly tech talks with internal speakers to share knowledge, at both org-wide and team-specific levels
  • Architected Databrick's distributed CI system, an elastic distributed task runner with improved stability, scalability, and usability to replace our aging Jenkins infrastructure. Elastically scales up and down 10,000s of cloud CPUs daily to run CI workflows while being robust against misuse, bugs, and underlying infrastructure failures.
  • Architected Databricks' elastic "Dev Box" service: on-demand, high-performance cloud development environments, managing an elastic pool of 100s of remote development environments.
  • Re-architected Databricks' cloud integration testing platform from a rough prototype to a production-ready system, managing 10,000s of kubernetes pods split across multiple clusters, regions, and three different cloud providers
  • Optimized and sped up many core developer workflows (compiling Scala, CI validation, etc.) by 5-10x
  • Implemented the config language used throughout Databricks including its high-performance compiler (500-1000 times faster than the upstream implementation) and IDE plugin
  • Cloud cost optimizations, saving on the order of millions of USD/year. Storage optimizations, networking optimization, workflow efficiency optimizations, etc.


San Francisco, CA

Software Engineer - Developer Tools, Web Platform, Dropbox for Business

Aug 2013 - Oct 2016


    Hands-on Scala Programming

    • A 400-page book that teaches you how to use the Scala programming language in a practical, project-based fashion.

    • Available on Amazon (paperback) and Gumroad (e-book formats). Part of the official book recommendations on the Scala Language website

    Open Source


    I authored and maintain a number of popular, widely-adopted open-source libraries. These form a large part of the open-source Scala ecosystem, and total over 20,000,000 monthly downloads. Some highlights include:

    Ancient History

    Massachusetts Institute of Technology

    Cambridge, MA

    Undergraduate Computer Science, GPA 4.8/5.0

    Sep 2010 - Jun 2013


      San Francisco, CA

      Software Engineer Intern, API Team

      May 2012 - Aug 2012


        Palo Alto, CA

        Software Engineer Intern, Messaging Team

        May 2011 - Aug 2011

          Singapore Armed Forces


          Lieutenant, Platoon Commander, 35th Battalion Singapore Combat Engineers

          Jan 2008 - Nov 2009


            Featured Articles

            More Articles on my personal programming blog

            Featured Talks

            A Deep Dive into the Mill Scala Build Tool

            The com.lihaoyi Ecosystem: Executable Scala Pseudocode that's Easy, Boring, and Fast!

            Scala at Scale at Databricks

            Getting Things Done in the Scala REPL

            Speedy Scala Builds at Databricks

            More Talks on my personal programming blog