Colin Lin
Software Engineer at Stripe
AI Agents & LLM Infrastructure
Toronto ON |colin.lin@mail.utoronto.ca
I'm a Software Engineer working on AI Agents and LLM-powered systems, with experience across frontend and backend.
I focus on building reliable, production-ready infrastructure and user-facing applications that deliver real-world impact.
Experience
Software Engineer
StripeOctober 2024 - Present
- Built and scaled an internal AI agent platform powering 170K+ weekly executions, automating merchant risk review workflows and driving $4.25M+ annualized impact (Python, Java, LangChain, LangGraph)
- Led development of an internal ChatGPT like LLM chat platform with 10K+ monthly active users, enabling MCP tool access, file/image uploads, and threaded conversations (React, TypeScript, Node.js, Go)
- Contributed to core infrastructure for a centralized LLM gateway handling 13B+ tokens/day across 250+ use cases, enabling model routing (OpenAI, Azure, AWS Bedrock), token/cost observability, and rate limiting
- Reduced LLM inference costs by 47% ($5.6M/year) by implementing Anthropic prompt caching with checkpoints across system prompts, tools, and conversation history to maximize cache hit rates in AI agent workloads
- Led resolution of a high severity production incident in 74 minutes impacting 100+ engineers by diagnosing a cascading failure across client hooks, rate limiting, and Redis, and implementing fixes to prevent recurrence
- Reduced MongoDB latency from 9s to < 1s by profiling slow queries, validating bottlenecks via workload replay, and applying targeted index optimizations under production load
Software Developer
Konrad GroupSeptember 2023 - August 2024
- Developed new frontend features for a major airline's flight booking application using Vue.js, impacting over 1 million users
- Built online contests and promotional pages for a major real estate client using Next.js and Contentful CMS
- Accelerated internal IT processes by 300% by automating manual tasks using Python and Selenium
- Mitigated fraudulent contest entries by implementing browser fingerprinting using JavaScript
Teaching Assistant
University of Toronto ScarboroughJanuary 2023 - April 2023
- Developed highly effective Angular and CORS tutorials for CSCC09 Programming on the Web
- Reinforced students’ understanding of web technologies, RESTful APIs, cloud deployment, and containerization with Docker
- Honed communication, mentorship, and leadership skills to foster an engaging learning environment
Cloud Full Stack Engineer
HSBCDecember 2021 - December 2022
- Developed cloud‑based web apps for HSBC Wealth Compass and US Product Onboarding using React and Redux
- Engineered RESTful APIs and API Orchestration layer using Spring Boot and Express.js microservices deployed on AWS
- Reduced maintenance cost by 40% by migrating legacy JavaScript codebase to TypeScript
- Worked closely with a cross time‑zone Agile Scrum team to support systems critical to Retail Banking across North America
- Mentored 3 new employees and interns on frontend development, API design, and advanced product knowledge
Software Developer
Ontario Institute for Studies in EducationOctober 2021 - June 2022
- Implemented new tools for collaborative learning software using Angular, Fabric.js and Firebase
- Established real-time data updates on virtual classroom whiteboards with over 30 concurrent users using socket.io
- Built a data collection framework for researchers to analyze classroom activity and generate reports
Software Developer
University Of Toronto ScarboroughSeptember 2021 - February 2022
- Analysed trends across global news sites by constructing data visualizations using Python, pandas, and Matplotlib
- Improved the efficiency of the Python website crawler by 50% by applying filters and caching data
- Served browser-accessible Jupyter Notebooks for researchers using Jupyterhub deployed on the cloud
Software Engineer
UofT HatcheryMay 2021 - October 2021
- Developed time-saving tools for the administrator dashboard using Vue.js, PHP, and WordPress
- Worked closely with senior developers to find and resolve bugs on the website
- Designed MySQL database schemas to store user data and survey responses
Software Developer
Cineplex Digital MediaSept 2020 - April 2021
- Led the development of custom web applications and digital signage for RBC, Citizens, and Scotiabank
- Adapted HTML, CSS, and JavaScript projects to serve different countries, currencies, and languages
- Reduced maintenance cost by 90% by rebuilding a legacy application using React
- Worked closely with creative teams to convert designs and requirements to interactive applications
Education
Honours Bachelor of Science
University of TorontoComputer Science, Software Engineering Specialist
GPA: 3.88
Sept 2019 - August 2023
Projects
TalkLab
Tool for researchers to collect data to fine-tune large language models and study user interaction with AI chatbots
Skills
Languages
Python, TypeScript, JavaScript, Go, Java, HTML, CSS, C, Swift, Kotlin, PHP
Frameworks and Libraries
React, Node.js, LangChain, LangGraph, Next.js, NumPy, pandas, Spring Boot, Angular, Vue.js
Databases
MongoDB, MySQL, PostgreSQL, Neo4j
Concepts
RESTful APIs, Object Oriented Programming, MVC Architecture, Microservices, Agile Scrum
Tools
Git, Docker, Linux, AWS, Splunk, Postman, nginx, Firebase, Jira
Soft Skills
Collaboration, Leadership, Teamwork