Senior Machine Learning Engineer

letgo, Barcelona

Buy and sell straight from your smartphone.

letgo's the largest and fastest growing app to buy and sell locally. With over 100M downloads and hundreds of millions of listings to date, letgo’s been named among the “Hottest Startups” by Wired and “Best Apps” by Google, and it’s the second fastest growing app in America since its 2015 launch. Business Insider calls letgo “the go-to app for selling your stuff” and it’s been featured by The New York Times, The Today Show, USA Today, The Verge, Fast Company, The Wall Street Journal, Fortune and hundreds of others worldwide.

Already among the most popular apps in America, letgo’s marketplace is filled with everything from electronics and cars to clothing and furniture. Listing something on letgo is as simple as taking a photo thanks to its advanced technology. It’s the only app of its kind that can automatically title and categorize an item using artificial intelligence. Plus, users can easily browse local listings, chat instantly in the app, and view each other’s profiles, ratings and reviews.

Based in our New York and Barcelona offices, our team of over 230 represents more than 30 nationalities. Fueled by our diverse expertise, letgo’s goal is to build the largest marketplace of its kind in the world. We’re looking for people who are as passionate as we are about creating something our users love and - just as importantly - who are excited by the challenge.

As a Machine Learning (ML) Engineer, you will be working closely with the Data Engineering and Data Science teams in order to develop and deploy ML models that power features used by millions of people.

We’re looking for someone who wants to build something huge and that people love because it makes their lives simpler:

We’ve built a company for people who want to do impactful work, surrounded by great people. We have a well-defined, mature culture — and we’re always making it better.

Your challenge:

  • Build infrastructure to support rapid development and deployment of ML models
  • Identify opportunities for application of ML across letgo
  • Support Data Engineering and Backend teams to adopt best practices and infrastructures to enable integration of ML models anytime anywhere
  • Work with Data Engineering teams to build a Data Platform that enables fast iteration in development and deployment of ML models

You must have:  

  • PhD. or MSc. in Computer Science, Mathematics, Statistics or related fields
  • Proven experience building, testing, deploying and maintaining ML models for low-latency, high-throughput production requirements
  • Deep understanding and experience with ML deployment architectures under batch and streaming scenarios (data lake, feature stores, model serving, monitoring and instrumentation, etc...)
  • Strong software engineering skills and advanced knowledge in at least one of the following: C++, Java, Scala or another OO compiled programing language
  • Extensive experience with big data platforms and tools: Spark, Hadoop, Kafka, Cassandra, Hive, Presto, etc.
  • Strong quantitative skills (statistics, probability, machine learning) as well as knowledge of algorithms/data structure

Nice To Have

  • Experience with on-device machine learning   
  • Experience with mobile Deep Learning models (Tensorflow lite, Apple's coreml) and model quantization/compression techniques
  • Familiarity with AWS ecosystem
  • Experience in a Data Scientist role
  • Knowledge of the Scala language and frameworks for building service-oriented architectures

letgo perks:

  • 100% covered medical, vision, and dental care premiums for you and your family
  • Competitive salary and stock options
  • Beautiful, new office in the heart of Soho and along the beach in Barcelona
  • Potential opportunities to travel to - and work in - both of our offices
  • Robust relocation package
  • Massage therapy (Barcelona office)
  • Fully stocked kitchens
  • Team-building activities
  • Language and other courses

letgo is proud to be an Equal Opportunity and Affirmative Action employer. Ensuring a diverse and inclusive workplace where we learn from each other is core to letgo's values. We do not discriminate based upon race, religion, color, national origin, gender (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender, gender identity, gender expression, transgender status, sexual stereotypes, age, status as a protected veteran, status as an individual with a disability, or other applicable legally protected characteristics.

About letgo

With over 100M downloads and 400M listings, letgo is the biggest and fastest growing app to buy and sell locally. One of America’s most popular apps, letgo’s marketplace is filled with everything from electronics, cars and collectibles to housing, clothing and furniture. With innovative features like video listings and letgo Reveal, the free app makes it easy to list what you don’t need and find great deals nearby on anything you do. Listing something is as simple as taking a photo because letgo’s technology automatically suggests a title, price and category. letgo was founded in 2015 by Alec Oxenford and Jordi Castello, with cofounder Enrique Linares joining soon after. Business Insider calls letgo “the go-to app for selling your stuff” and it’s been featured by The New York Times, The Today Show, Fast Company, The Wall Street Journal, Fortune and many others worldwide.

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Want to learn more about letgo? Visit letgo's website.