It all started with an idea at Block in 2013. Initially built to take the pain out of peer-to-peer payments, Cash App has gone from a simple product with a single purpose to a dynamic app, bringing a better way to send, spend, invest, borrow and save to our millions of monthly active users. With a mission to redefine the world's relationship with money by making it more relatable, available and accessible, at Cash App you'll have the opportunity to make a real-world impact with your career.

Today, Cash App has thousands of employees around the world with a culture geared toward creativity, collaboration and impact. We’ve been a distributed team since day one, and continue to value working across time zones and continents both remotely and in our Cash App offices.

Our offices are great, but many of our roles can be done remotely from the countries where Block operates. We tailor our experience to champion our employees’ creativity and productivity wherever they are. 

This opportunity is only open to students who are currently enrolled in either a Masters or PhD program and offers an 8-month paid term (with a possibility for extension) on Cash App's Risk AI team starting in Summer or Fall of 2022. If you've already graduated (or are set to graduate before the end of 2022), please apply to one of our full-time roles.

Machine Learning is an integral part of how we design products, operate, and pursue Cash App’s mission to serve the unbanked as well as disrupt traditional financial institutions. Our massive scale and deep trove of transaction data create an endless number of opportunities to use artificial intelligence to better understand our customers and offer new products and experiences that can improve their lives. We are a highly creative group that prefers to solve problems from first principles; we move quickly, make incremental changes, and deploy to production every day. 

The objective of this project is to systematically test and validate advanced sequential models (including bi-directional RNN, auto-regressive CNN, transformers, and neural controlled differential equations) on time-series data generated within Cash. Cash App collects a variety of signals about how our customers interact with the platform - we will determine the best way to make use of these data using state-of-the-art deep learning methods.

Deep sequential models offer the potential to significantly improve our ability to detect fraudulent behaviour while reducing the time-consuming (and hence expensive) process of manual feature-creation and curation. Models will be benchmarked for automated extraction and detection of fraud patterns within sequential transactional data (e.g. cash in, cash out, p2p, etc).

Over the course of your term, you will:

• Craft standardized and reusable datasets for consistent benchmarking and testing of sequence models
• Provide quantitative assessment of the advantages and disadvantages of different model classes based on accuracy, precision/recall, training cost, training time, data requirements, and interpretability
• Create a modular and well documented codebase which can be easily used for other sources of sequential data within the Block ecosystem

Technologies we use (and teach):

• Python, NumPy, Pandas, PyTorch, TensorFlow, keras, JAX, Julia
• MySQL, Snowflake, GCP/AWS and Tableau
• Java

You have:

• 1-2 years of experience with applied Deep Learning
• Proven ability to implement in practice neural network architectures described in literature using frameworks such as PyTorch or Tensorflow
• Experience with advanced techniques like embeddings, irregular sequence modeling and time-series forecasting, uncertainty quantification, graph neural networks, anomaly detection,  and neural ODEs is a big plus
• An appreciation for the connection between the software and models you build and the experience it delivers to customers
• Have a curious, passionate, growth-oriented mindset

We’re working to build a more inclusive economy where our customers have equal access to opportunity, and we strive to live by these same values in building our workplace. Block is a proud equal opportunity employer. We work hard to evaluate all employees and job applicants consistently, without regard to race, color, religion, gender, national origin, age, disability, pregnancy, gender expression or identity, sexual orientation, citizenship, or any other legally protected class. 

We believe in being fair, and are committed to an inclusive interview experience, including providing reasonable accommodations to disabled applicants throughout the recruitment process. We encourage applicants to share any needed accommodations with their recruiter, who will treat these requests as confidentially as possible. Want to learn more about what we’re doing to build a workplace that is fair and square? Check out our I+D page. 

Additionally, we consider qualified applicants with criminal histories for employment on our team, and always assess candidates on an individualized basis.

Block, Inc. (NYSE: SQ) is a global technology company with a focus on financial services. Made up of Square, Cash App, Spiral, TIDAL, and TBD54566975, we build tools to help more people access the economy. Square helps sellers run and grow their businesses with its integrated ecosystem of commerce solutions, business software, and banking services. With Cash App, anyone can easily send, spend, or invest their money in stocks or Bitcoin. Spiral (formerly Square Crypto) builds and funds free, open-source Bitcoin projects. Artists use TIDAL to help them succeed as entrepreneurs and connect more deeply with fans. TBD54566975 is building an open developer platform to make it easier to access Bitcoin and other blockchain technologies without having to go through an institution.