Principal ML Engineer - NLP

The Position

Who we are

Twitter Cortex is the central machine learning organization at Twitter. Cortex’s mission is to empower internal teams to efficiently leverage machine learning by providing platform, modeling and research expertise while advancing the ML technologies within Twitter. 

Cortex Signals is the Applied Machine Learning pillar of Twitter Cortex. We apply machine learning expertise in various areas including NLP, Computer Vision, Topic modeling, Knowledge Graphs and partner closely with various teams at Twitter. We apply and advance state of the art ML techniques in these domains to invent new models and systems that can be used to improve various Twitter experiences for our customers. We tackle Twitter specific ML challenges such as the real-time, ever changing nature of our data and limited context. 

We encourage publishing papers while focusing on solving real-world problems that improve Twitter for our customers. We operate at scale whilst ensuring fair and ethical use of our models and data.

What You’ll Do

You are a strategist and will provide technical leadership to Cortex Signals, Twitter’s Applied Machine Learning organization. We’re looking for a Principal level individual contributor with a track record of successfully delivering machine learning models and systems end to end, who can lead, mentor and grow NLP modelers and engineers, along with the Engineering Manager.

You will partner with product management and your technical leads to build a high-value roadmap of innovation for your organization. You will lead by example to build your team culture in keeping with Twitter’s culture. You will partner with Engineering Managers in multiple organizations across Twitter and guide modelers and engineers with your technical expertise by contributing to design reviews and ideation. You will help mentor, coach and grow people.

You will work with our machine learning modelers and researchers to innovate and build new models and systems, improve and enhance existing ML systems as well as discover new opportunities to apply machine learning to solve critical problems. Your responsibilities will include:

  • Mentoring: Mentor the professional development of the team, in conjunction with the Engineering Manager.
  • Planning / Alignment: Plan and collaborate with other teams Twitter in delivering impactful changes, whilst working together with other Cortex teams for the long term. 
  • Provide oversight: Lead strategy with engineers and researchers to understand how everything fits together and how best to deliver meaningful impact. Understands when ML is applicable and when it is not, and what are the risks.
  • Execution: Make decisions which balance between immediate impact and long-term bets, as well as managing resourcing and prioritization.
  • Relationship management: You will forge close relationships with the Principal and Staff engineering community as well as with engineering and product management leaders in multiple organizations at Twitter and you will partner with them to deliver impact.
  • Cross functional partnership: Work closely with other teams from across the company to deliver impactful projects which may involve multiple disciplines. 



Who You Are

  • You are a Strategist and a lead looking to serve the team and achieve team goals.
  • You are an able problem solver who enjoys identifying business problems to which core machine learning techniques can be solved. You are adept at identifying simple solutions to complex problems. 
  • You will have a solid understanding of Machine Learning, Deep Learning and NLP or Knowledge Graph.
  • You have prior experience as a machine learning modeler/scientist/researcher/engineer and are familiar with the workflow and motivations of machine learning modelers and engineers.
  • You are a strong source of machine learning and engineering talent and are comfortable closing applicants for your team and the business.
  • You have technical depth in machine learning and see the “big picture”. You understand the differences in technical disciplines (particularly on ML side), and which problems are for ML to solve and which are not.
  • You are up to date with recent developments in Machine learning and are familiar with current trends in the wider ML community and also preferably in one or more of Natural Language Processing, Topic Modeling or Knowledge Graphs.
  • You are an innovator with a proven track record conceiving of significant innovations that result in substantial positive impact to customers. 
  • You have proven execution track record that is customer-centric in prioritization - looking to deliver projects that serve the company’s needs and understand the impact.
  • You are a good communicator with clear and concise, active listening and empathy skills. 
  • You collaborate well with teams with different backgrounds / expertise / functions.
  • You bring a strong perspective that motivates engineers to develop simple, pragmatic solutions to complex problems.
  • You have the technical experience to win respect from ML modelers and engineers and NLP experts and are comfortable diving into the fray to help drive resolution.


  • MS or PhD in machine learning, computer science, math or equivalent work experience. PhD is a plus. 
  • 10+ years of experience as a hands on expert-level practitioner of machine learning and/or natural language processing. You have built large scale machine learning models and systems. Experience in modeling in Natural Language Processing is a plus. Having conducted research and published peer-reviewed articles in a Machine Learning field is a plus. 
  • 5+ years of experience leading large ML initiatives across cross functional teams in multiple organizations. 
  • Track record of innovation and having taken large machine learning based products and features from conception to successfully delivering value to customers in production. 
  • Understand cost of software development / tech debt and long-term maintenance.
  • Experience driving impact through cross-functional leadership.
  • Exceptional written and verbal communication skills.
  • Strong analytical abilities.
  • You have a get stuff done attitude, have great positive energy, and thrive in a fast paced environment.
  • You are passionate about technology and can keep up with the latest developments.
  • You are a skilled technical influencer and have a track record of successfully influencing product direction. You have a respectful, collaborative approach that earns the trust of your peers and stakeholders. 
  • You invest in the learning and growth of the people you lead. 
  • You communicate effectively.  

Additional Information

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

San Francisco applicants: Pursuant to the San Francisco Fair Chance Ordinance, we will consider for employment qualified applicants with arrest and conviction records.


Machine Learning


Boston, Seattle, San Francisco



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