Twitter, Inc. (NYSE: TWTR) is the best and fastest place to see what’s happening and what people are talking about all around the world. From breaking news and entertainment to sports and politics, from big events to everyday interests. If it’s happening anywhere, it’s happening first on Twitter. Twitter is where the full story unfolds with all the live commentary and where live events come to life unlike anywhere else. Twitter is available in more than 40 languages around the world. The service can be accessed at Twitter.com and on a variety of devices. For more information, visit about.twitter.com

Are you an engineer who’s interested in tackling complex adversarial problems and passionate about defending online users against terrorism, violent extremism, and coordinated harm? Do you love working on challenging, society-impacting problems that require a multi-disciplinary approach, creative solutions, and rapid product iterations? Will you be proud to work on a real-time, scalable system that serves millions of users daily? If so, you should join us. 

Who We Are:

The Harmful Group Activity engineering team is responsible for building scalable systems that keep terror organizations, violent extremist groups, and other bad actors at bay. We use applied ML and relevance techniques to make Twitter safer and to limit the ability of these groups to exploit our platform. Our team works across the product to detect harmful users and content, increase action on bad actors, drive changes in user behavior, and detect and remediate accounts that are violating the terms of service on Twitter. We develop, maintain, and contribute to several machine learning models and systems, including: 

• Models that detect networks of affiliated accounts 

• Media recognition services that detect violative content on images and videos

• Textual analysis to detect variants and obfuscations

• Models to prioritize human review of accounts violating Twitter's policies to more quickly take action and limit their damage 

• Real-time rule engines and clustering systems to identify and action on clusters of bad actors at scale 

What You’ll Do:

The Harmful Group Activity team at Twitter is building cutting-edge technology to reduce the ability of bad actors to operate on our platform. You will participate in the engineering life-cycle at Twitter, including designing distributed systems, writing production code and data pipelines, conducting code reviews and working alongside our infrastructure and reliability teams. You’ll apply data science, machine learning, and/or graph analysis techniques to a variety of modeling and relevance problems involving users, their social graph, their tweets, and their behavior.

Who You Are:  

• You’re an engineer, applied data scientist, or machine-learning engineer who wants to work on exciting algorithmic and deep infrastructure issues to improve the health of the public conversation on Twitter. 

• You’re experienced at solving large-scale relevance problems and comfortable doing incremental quality work while building brand new systems to enable future improvements. 

• You are experienced in one or more of the following: machine learning (including deep learning), information retrieval, recommendation systems, social network analysis. 

• You are a strong technical advocate with a background in Java, C++, or Scala, and Python. 

• Experience with a number of ML techniques and frameworks, e.g. data discretization, normalization, sampling, linear regression, decision trees, deep neural networks, etc 3+ years experience with one or more DL software frameworks such as Tensorflow, PyTorch, Theano. 

• You strive to find the right balance between moving fast to deliver quality improvements to users and accumulating technical debt that drags down productivity. 

• You have a collaborative working style with a strong focus on disciplined execution and results. 

• You like to ground decisions in data and reasoning and solve root causes of problems rather than surface issues. 

• You are adept at communicating relevant information clearly and concisely. 

• You look ahead to identify opportunities and thrive in a culture of innovation.

Requirements: 

• M.S. or PhD in Computer Science or Machine Learning related degree; or equivalent work experience in the field 

• 2+ years experience leading and delivering effective ML solutions for large scale production use cases.

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.