Twitter: Senior Software Engineer (Backend) - ML Platform Tools - Cortex
245 West 17th Street
New York, NY 10011

Who We Are

Cortex empowers internal teams to efficiently leverage ML by providing a platform and by unifying, educating, and advancing the state of the art in ML technologies within Twitter. We win when our customers win by helping our users stay informed, share and discuss what matters; by serving the public conversation. We’re building an AI-first company and every major initiative is increasingly dependent on the successful application of machine learning. Cortex is at the nexus of this evolution.

Our team of ML software engineers are constructing one of the strongest machine learning platforms in the world by marrying the latest ML industry practices with engineering excellence and the need to perform at Twitter scale. Our customers are all the ML engineers at Twitter and our goal is to provide tooling that allow these engineers to focus on what they are good at, building ML models, and abstract the way the complexities of bringing these models into a production environment with novel approaches.

We care deeply about:

  • Engineering excellence such as good design abstractions, API stability, unit testing, leading best practices for other engineers to follow, and solid documentation.
  • Staying abreast and compatible with a quickly shifting technology landscape for ML platform components and related open source solutions.
  • Creating the best ML Platform environment for Twitter that provides an exceptional developer experience for our engineering customers.
  • Encouraging engineering creativity and innovative solutions

Our Current projects include:

  • Developing an ML focused workflow platform powered by Airflow 
  • Building out Jupyter Notebooks as a first class offering at Twitter
  • A central web based UI environment for ML tooling at Twitter

What You'll Do

If this sounds like a team you want to be part of, great! We are looking for engineers who are passionate about writing code, have a desire to learn new technologies, love working in collaborative teams, and are committed to serving their customers.

Your responsibilities include:

  • Designing elegant abstractions, shareable libraries, and robust APIs.
  • Actively looking for ways to improve the end-to-end experience for developers across Cortex’s product portfolio.
  • Educate and support our customers with excellent written documentation, forming/sharing best practices, and by coaching.
  • Integrating products seamlessly with Twitter’s serving, data infrastructure, and cloud environments.
  • Working closely with product managers, engineers and stakeholders across the company.
  • Shaping the direction of our toolchain and product portfolio.
  • Adapting, extending and contributing to open source and third party solutions to seamlessly function within our toolchain.

Who You Are

  • You find building platform tools for customer engineers exciting and inspiring.
  • You have a passion for machine learning.
  • You wish to tackle hard product and engineering challenges working in concert with smart people.
  • You're excited to ramp up on new technologies to build awesome things with us!
  • You have the ability to take on complex problems, learn quickly, iterate, and persist towards a good solution.
  • You are adamant about studying customer needs and enabling their success through our products.
  • You take pride in polishing and supporting our products.
  • You have a strong desire to craft easy-to-use and delightful customer engineering experiences.


  • You have 5+ years of applicable software engineering experience
  • You have a sound grasp on OOP concepts, data structures and algorithms.
  • You have a durable approach to writing unit and integration tests.
  • You have working knowledge of an OOP language (e.g. Java or Scala) and a scripting language (e.g. Python)
  • You have knowledge of distributed computing architectures.
  • You easily articulate complex concepts in writing and speech.
  • BS, MS, or PhD in Computer Science or equivalent work experience.
  • You’re no stranger to microservices.
  • You have operational knowledge of relational and non-relational databases (e.g. MySQL/Postgres and Cassandra/ElasticSearch).

Equal Opportunity Statement

We are committed to an inclusive and diverse Twitter. Twitter is an equal opportunity employer. We do not discriminate based on race, color, ethnicity, ancestry, national origin, religion, sex, gender, gender identity, gender expression, sexual orientation, age, disability, veteran status, genetic information, marital status or any legally protected status.


Hiring Process

Step 1

After you apply, a recruiter may reach out to you for an introductory call.

Step 2

If your background is a match for the role, you may phone interview with 1-2 people.

Step 3

If you continue through the process, you will come onsite 1-2 times to interview with a total of 5-10 people.