# Ertai Duo

> Software Engineer

Location: San Francisco Bay Area, United States
Profile: https://flows.cv/ertai

## Work Experience
### Software Engineer @ City Storage Systems
Jan 2024 – Present
SupportGPT
- Engineered an LLM-powered AI agent for customer support, automating the resolution of frequent inquiries by integrating custom widgets and procedural runbooks, which significantly improved response consistency and operational efficiency.

GraphQL Federation
- Led the migration from a monolithic to a federated GraphQL architecture to enhance system scalability and maintainability.
- Designed and implemented a streamlined subgraph development framework, reducing boilerplate code and accelerating development cycles.
- Optimized performance across the GraphQL gateway and all subgraphs by diagnosing and resolving critical issues such as memory leaks and thread leaks, leading to improved resource efficiency and system stability.
- Developed and supported code generation tooling for frontend, Android, and iOS/Swift to ensure seamless integration with the federated GraphQL schema.

### Software Engineer @ DoorDash
Jan 2020 – Jan 2023
Merchant payout and tax calculation

### Software Engineer @ Uber
Jan 2017 – Jan 2020 | San Francisco Bay Area
Realtime Rider Pricing:
- Built realtime rider pricing service for serving prices for ride-sharing product based on origin, destination, time, and business strategy with machine learning models(predicting driver payout and conversion rate) using Dropwizard framework(Java)
- Built pricing plans management system for generating, deploying, deprecating pricing plans for ride-sharing product with ReactJS, Spark, Dropwizard
- Supported migrating demand model for predicting conversion rate from a micro-service to Michelangelo, a Uber-wide machine learning platform

Supply Data Platform:
 - Built a micro-service to provide source of truth for driver state change and supply summary to other services including insurance, fleet management, driver earnings, etc.

Realtime Insights:
 - Built a Go micro-service that generates driver related business metrics in realtime for market health monitoring using Kafka and Cassandra, supports 200k TPS at peak

Blacklist/Dispatch Integration:
 - Built a data backfill pipeline for blocking driver/rider if you gave/received 1-star rating to/from this person with Spark, and Piper(a job-scheduling service)

Geo-triggers:
 - Ingesting global drivers' location update and generating events about drivers entering/existing/dwelling in geofences

### Software Development Engineer @ Amazon
Jan 2016 – Jan 2017 | Greater Seattle Area
Development and Operation of:
 - Offer Service
 - Offer Service Pre-computation Reactors
 - Remote Catalog Service
 - Catalog Responder APIs

### Design Engineer @ Oracle
Jan 2015 – Jan 2016 | San Francisco Bay Area
Analog & Mixed-Signal IC Design
Digital IC Design
Mixed Signal Verification
Backend Flows


## Education
### Bachelor's degree in Electronic and Information Engineering
Zhejiang University
Jan 2009 – Jan 2013

### Master's degree in Electrical and Computer Engineering
Texas A&M University
Jan 2013 – Jan 2014

### Non-degree in Computer Science
Stanford University
Jan 2016 – Jan 2016


## Contact & Social
- LinkedIn: https://linkedin.com/in/ertai-duo-91b5846a

---
Source: https://flows.cv/ertai
JSON Resume: https://flows.cv/ertai/resume.json
Last updated: 2026-03-22