University of Washington

Engineer / Entrepreneur / Startup advisor and investor

Tokyo, Tokyo, Japan

Mercari, Inc.

Microservices Architect

We have stringent data accuracy and integrity, security, regulatory, and product requirements. 

As a technical lead and principal engineer, I designed and built the majority of our systems following our CTO's technical vision:

-  designed and built a highly secure document storage system where we store sensitive financial documents (such as monthly statements) for our users. 

-  designed and built a generic payment system (which integrates with a major bank’s back-end) that’s highly secure, accurate, and reliable. The system is responsible to accept inbound borrower payments and make outbound payments to loan investors.

-  designed and built a communication platform that reliably sends emails and text messages and manages notification preferences

-  made critical contributions to the design and implementation of our core loan accounting system, which enables automation of solutions to challenging loan accounting problems that no one else was known to be able to automate to date. By automation, the cost of loan servicing dramatically reduces so loans become less expensive and borrowers have more flexible options (hence delinquency decreases)

-  designed and built on internal systems to help increase engineer productivity, such as our build and deployment systems, service, database and configuration discovery systems, infrastructure automation, testing framework, visibility (metrics and logs management) and infrastructure monitoring and alerting

-  designed a highly secure and flexible dynamic authorization system that provides bank-level security to sensitive data and enables our loan servicing product to onboard multiple customers (loan originators)

-  led technical operations (devops) and security

-  peer reviewed all other system designs
 
-  led the engineering side of SOC2 effort. We got SOC2 in 2018 with 0 exceptions
 
-  heavily involved in planning, conducting, and organizing projects

-  mentored engineers

Scratch

Software Engineer

Pinterest helps people to explore ideas and achieve them in real world. Hundreds of millions of people actively use the product. 

-  As an early member of the TechOps team (which then became the Cloud Engineering team), I built the first viable version of the integration pipeline and deployment systems that all of the product teams at Pinterest used to efficiently test and deploy (and rollback) new code to hundreds (and later thousands) of servers without interruption of service. The work allowed software services to be implemented much faster and with better quality, and became instrumental in helping Pinterest make bigger leaps in innovation. 

-  Later at the BlackOps team (which later became the Real Time Processing and Response team), I built a streaming processing system that helped fighting spam that we were able to reduce the number of engineers required for fighting spam from about 9 to .5 (half of an engineer’s time) while reducing spam to such a small amount that it stopped being a company concern.  We were also able to make the system available to other product teams so that they could easily describe and execute millions of actions that were guaranteed to be taken in order. 

-  Led project planning and prioritization. 

-  Mentored other engineers.

Pinterest

Livestar was a mobile app that allows people to get trustworthy ratings and reviews of things in different categories (restaurants, menu items, books, wine, apps, music, movies, etc). Users can choose the source of the ratings and reviews (for example, specific people or group of people, or people who has similar taste with you) and discover interesting things in real time. 

As a part of the founding engineering team:

-  Built core features of the back-end systems that support Livestar apps and Web UI. We had a huge amount of data, and based on arbitrary input (of category, location, source of the ratings and reviews), the system needed to be able to calculate and return the results in real time. 
-  Automated and managed system infrastructures as code using Opscode Chef
-  Built Livestar web pages and email newsletters

As one of the first engineers:

-  Worked on the design and development of data collection and aggregation systems, authentication components, fine-grained authorization system, identity management, search, environments support, and many other core components, as well as automating the migration and validation of massive amounts of data among incompatible versions of the systems. 

-  Build out the core features of the Opscode Platform (Hosted Chef), a high volume web service for the configuration of network-connected devices.

-  Worked on the first versions of the management console and command-line based client tools customers used to administer their infrastructure managed by Hosted or Open Source Chef.

-  Collaborated with third-party consulting firms on community features which allowed customers to easily share and use modules of Chef code

-  Worked on “quick start” features which helped business teams demonstrate the value of Chef to new customers and allowed customers to launch and configure a server with a certain role with just a few clicks. Such features helped provide customers an easy proof-of-concept and were extremely valuable to the business.

-  Designed and built a front-end web interface for Chef. The web interface is a primary way through which end users access the Platform and is the "face" of Chef to its customers.

-  Created and mined large datasets. Hosted Chef collects and organizes a tremendous amount of data about the systems and services that run against it. For the Platform to be useful, it must be able to manipulate this data quickly and efficiently.

-  Community management within the Chef customer community and the open source Chef project community.

-  Helped recruit and train new employees.

Nuo Yan