Erik Bernhardsson    About

Contact information

️ 690 Greenwich Street, Apt 4A, New York NY 10014
Swedish citizen, green card holder


I am an engineering manager who manages a team of about 40 engineers and 10 product managers at Better. My specialties include engineering management, building consumer technology, machine learning, and math. I have managed teams for almost ten years, and I have been doing machine learning for more than ten years.


Work experience

Head of Engineering
Feb 2015 –
New York City
  • Joined as one of the first 10 employees.
  • Working closely with the recruiters, doing 800+ interviews in the first 3 years.
  • Taking the engineering team from 2 people to 40.
  • Also running the product team, consisting of about 10 people.
  • Migrating the legacy tech stack to AWS, Postgres, Python, and microservices.
  • Writing code together with the team, building many critical components in Python and Node.js.
  • Managing and mentoring engineers.
  • Having several managers reporting to me.
  • Actively involved in fundraising, meeting investors and the board.
Engineering Manager
Feb 2009 – Feb 2011 (Stockholm),
Oct 2011 – Feb 2015 (New York City)

2011 – 2015 (New York City)

  • Built up the core of the music recommendation system (80% of the current system is still my algorithms, according to people still at Spotify).
  • Built an open sourced a data pipeline engine (Luigi) still used by Spotify and many other companies (Capital One, Foursquare, …).
  • Built an open sourced a library for approximate nearest neighbors (Annoy) still used by Spotify and other companies (Uber, Instacart, …).
  • Managed the music recommendation team, consisting of about 15 engineers.
  • Invented and implemented many large scale machine learning algorithms, processing terabytes of data daily.
  • Awarded three patents on recommender systems.
  • Brought in a deep learning researcher in 2014 and prototyped a content-based music recommendation system.
  • Tech lead for a larger group of engineers working on music recommendations, about 25 engineers in total.
  • Spoke at several conferences and meetups.
  • Left when Spotify was roughly 1,600 people.

2009 – 2011 (Stockholm)

  • Joined in 2008 to work on my Master's Thesis when Spotify was roughly 30 people.
  • Joined full-time in February 2009.
  • Built and managed a small data team with three people reporting to me
  • Reported directly to the CTO.
  • Laid the groundwork for a our data strategy at Spotify.
  • Ran the first A/B tests, price sensitivity analyses, any many other analyses.
  • Built a system to simulate and quantify the ad inventory, and identified an opportunity to optimize ad delivery that saved several $MM/year.
  • Worked closely with the business team and sent them analyses going directly to labels and investors.
  • Left in Feb 2011, came back in Oct 2011 (after a brief stint at Graham Capital).
Graham Capital
High Frequency Trading, Associate
Mar 2011 – Sep 2011
Norwalk, CT
  • One half of a team managing a $700M+ portfolio.
  • Implemented high frequency trading strategies in C++ and C#, mostly for commodities and currency futures.
  • Researched new strategies in Python and R.
Software Engineer Intern
Sep 2006 – April 2007
Zurich, Switzerland
  • Took time off from university to work at Google for seven months.
  • Worked on embedded systems for Google's infrastructure.
  • Worked on large-scale data extraction for Google Maps.


Royal Institute of Technology (KTH)
Sep 2003 — Mar 2009
M.Sc. in Engineering Physics
  • Spent six months at TU Berlin as an exchange student.
  • Master's thesis ”Implementing a Scalable Music Recommender System“ was awarded best Master's Thesis in Sweden by Naturvetarna (a union).
  • Represented university at the ACM international collegiate programming championship twice – in San Antonio 2006 and Tokyo 2007.
  • Won the Nordic programming championship six times.
Danderyds Matematikgymnasium (high school)
Sep 2000 — Jun 2003


  • Co-organizer of the NYC Machine Learning meetup which has about 11,000 members.
  • I write a blog on software engineering which has about 200,000 readers per year.
  • Authored of a few open source projects: in particular Luigi which is a workflow management system with over 8,000 stars on Github, and Annoy which is a library for approximate nearest neighbors.
  • Fluent in Swedish, English, and German.