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Marika Lam

Senior Software Engineer

ABOUT ME

Hi, I'm Marika Lam

Senior Software Engineer

    • E-MAIL
    • marikaleelam@gmail.com
    • LINKEDIN
    • linkedin.com/in/marikalam
    • GITHUB
    • github.com/marikalam
    • MEDIUM
    • allaboutcode.medium.com

Hello and welcome to my page! My name is Marika Lam and I'm a Senior Software Engineer at Walmart Global Tech, based in the Silicon Valley. I lead engineering for Walmart's Promotions and Coupons platform and am building PromoGenie, an agentic AI platform that uses Claude and RAG-based retrieval to streamline promotion and coupon workflows. Before Walmart, I graduated from Boston University and worked at Rakuten in San Mateo.

In my free time, I enjoy yoga, playing tennis, cooking and anything that requires being outdoors. I also love writing tutorials and articles on my personal Medium page. You can see my apps and projects under the "Apps & Projects" section.

My Experience

May 2021 - current

Walmart Global Tech

Senior Software Engineer

• Lead engineering efforts for Walmart's Promotions and Coupons platform, building internal products that enable business teams to create, manage, and execute promotions across 11 international and U.S. markets.
• Serve as a tech lead for full-stack initiatives, driving architecture, design reviews, implementation, and modernization of promotion-management experiences using React, TypeScript/JavaScript, Java, Python, Node.js, REST APIs, and distributed backend services.
• Develop PromoGenie, an agentic AI platform that streamlines promotion and coupon workflows using LLMs, Claude, Python, TypeScript, ChromaDB, vector search, and RAG-based retrieval.
• Partner with product managers, backend engineers, platform teams, and business stakeholders to translate complex promotion rules and operational requirements into scalable product and technical solutions.
• Provide architectural guidance and technical leadership across the team, mentoring engineers, reviewing designs and code, and driving engineering standards for maintainability, performance, testing, and developer experience.
• Built automated end-to-end and API testing frameworks using Playwright and Nightwatch.js, expanding coverage across the Promotions UI and 30+ REST APIs.
• Worked on backend and data engineering for the Promotions platform, building services with Java, Spring MVC, REST APIs, Oracle, and Cassandra.

April 2017 - May 2021

Walmart Global Tech

Software Engineer III

Worked as a backend Java and database engineer on the Promotions platform before transitioning into a full-stack role, building RESTful services with Java, Spring MVC, Oracle, and Cassandra.

May 2015 - April 2017

Rakuten

Software Engineer

Worked on back-end infrastructure and services of the Ecosystem Department and Membership team by creating scalable APIs to be used by clients and its subsidiaries: RESTful web services (Java, Spring, Cassandra, RabbitMQ); batch processing and migration from Oracle to Cassandra (Scala, Spark, Java, Python); integration, unit and performance tests (Cucumber, JUnit, Gatling); development process organization (Confluence, Jira, Jenkins, Git); and code reviews and quality control (Git, Atlassian Stash, Jira). Worked at the Tokyo Headquarters office in 2015.

March 2014 - Dec 2014

Lubax

Software Engineer

Lubax is a smartphone-based clinical reference to identify skin lesions. The user takes a photo of a skin lesion and the app will search a proprietary image database of diagnosed lesions to identify a diagnosis. CBIR (content based image recognition) is used to discriminate skin-lesion types. I data mined 15,000+ image files of skin diseases for the iOS platform in Java and Python, and designed and developed the iOS app using Objective-C, C++, and the XCode IDE.

Dec 2011 - Sept 2013

Boston University

Assistant Database Administrator

Retrieved endowment-related data from DARWIN (Development and Alumni Relations Web-Based Information Network) database. Analyzed and validated reports before sending to sales and marketing, revenues, and other departments.

My Qualification

2011-2015

Boston University

B.S. Computer Science, Minor in Human Physiology

At BU, I was involved in many groups and activities. I worked as an Admissions Ambassador, leading campus tours for incoming students and parents, as well as hosted Open Houses.

I was also a member of Alpha Phi Omega, a community service fraternity, and completed 80+ service hours per semester. I spent my weekends volunteering at the Red Cross, Dana-Farber Cancer Institute, the Boston Food Bank, and various other places. I also enjoyed programming (not related to my school projects), so I joined Global App Initiative, where I created various iOS apps for non-profit organizations.

2007-2011

Los Altos High School

Apps & Projects

Apps

HomeDiary

Full-stack web app

Track your home's history and documents

HomeDiary is a private diary for your home. Sign in, add your properties, and log a timeline of everything that happens to them: purchase, damage, repairs, inspections, and more, each with photos and documents attached. Paperwork like purchase documents, insurance policies, and warranties gets its own place for each property, and every account only ever sees its own homes. The app has a typed REST API with JWT cookie auth and bcrypt password hashing, and uploads go straight to S3-compatible object storage. It runs as a single Docker service on Render.

Tech stack
  • TypeScript
  • React
  • React Router
  • Vite
  • Node.js
  • Express
  • Prisma
  • PostgreSQL (Neon)
  • Cloudflare R2 (S3 API)
  • JWT auth
  • Docker
  • Render
Open app Source on GitHub

KachunQuizer.ai

AI study app

Photo your notes, get quizzed on them

Take a photo of your notes or paste them in, and KachunQuizer.ai turns them into an Anki-style flashcard deck. Tesseract.js reads the text out of the photo in the browser. Claude then writes real comprehension questions from it, through a Cloudflare Worker that keeps the API key off the client. If that request fails, the app falls back to an offline generator that uses NLP to blank out the key word in each sentence, so a study session never hits a dead end. Each deck uses spaced repetition: facts you miss come back sooner, and facts you know show up less often.

Tech stack
  • JavaScript
  • React
  • Vite
  • Claude API
  • Cloudflare Workers
  • Tesseract.js (OCR)
  • Compromise (NLP)
  • Spaced repetition
  • PWA
Open app Source on GitHub

MathPop

Math game for kids

Multiplication, addition, subtraction

MathPop is a sibling to PitchPop that uses arithmetic instead of chords. Kids pick multiplication, addition, subtraction, or a random mix, then solve five-problem rounds with big colored cards, chimes, and confetti. They can tap an answer or write it by hand: a small neural network I trained on MNIST, with augmentation to handle messy kid handwriting, reads the digits right in the browser. The wrong answer choices come from common slip-ups, like being off by one factor or adding instead of multiplying, so getting it right means knowing the answer. Problems are read aloud with Piper TTS, and progress is saved on the device and broken down by operation.

Tech stack
  • JavaScript
  • React
  • Vite
  • Neural network (MNIST)
  • Canvas API
  • Piper TTS
  • PWA
  • GitHub Pages
Open app Source on GitHub

PitchPop

Music game for kids

Learn perfect pitch by colored chords

PitchPop started as a game we play at home: I play a chord on the piano, and my kids grab the matching color flag and shout it out. The app turns that into a quiz. Tap the rainbow to hear one of nine chords, pick its color from four choices, and get confetti and spoken feedback when you're right. The piano sound is synthesized from harmonics with the Web Audio API, so the app ships no audio samples. The voice is Piper, a neural text-to-speech model that runs in the browser through ONNX Runtime. There's also a free-play mode, plus a progress page for each child that tracks accuracy and which colors have come up. It installs to a phone's home screen as a PWA.

Tech stack
  • JavaScript
  • React
  • Vite
  • Web Audio API
  • Piper TTS
  • ONNX Runtime Web
  • PWA
  • GitHub Pages
Open app Source on GitHub

Hackathon & School Projects

PowerPay

Money20/20 Hackathon, Las Vegas

Pay online by digital check

Card payments cost merchants about 2.9% per transaction, and paying straight from a bank account online usually fails because there's no real-time check that the payment is good. PowerPay authenticates the payer and pays with a digital check drawn on their bank account, using the Feedzai API to score each payment for fraud before it goes through. I built the web app in Flask and deployed it on Heroku.

Tech stack
  • Python
  • Flask
  • JavaScript
  • HTML/CSS
  • Feedzai API
  • Heroku
Source on GitHub

4Sight

US Bank / Mastercard Hackathon finalist

Cash-flow forecasting for small businesses

4Sight helps small businesses manage working capital by forecasting cash flow by day, week, or month. It starts from a worst-case projection that assumes every customer pays on the last possible due date, then updates in real time by checking the business's bank account through the US Bank API, so invoices that are paid early move the forecast right away.

Tech stack
  • Python
  • Flask
  • JavaScript
  • HTML/CSS
  • US Bank API
Source on GitHub

Changi Along The Way

Changi Airport Hackathon

A journey companion to your gate

At Changi Airport, 60% of passengers arrive less than two hours before their flight, and even early travelers worry about missing it. Changi Along The Way predicts how long it will take to get to your gate and suggests a personalized list of places to stop along the way, so you can relax without losing track of time.

Tech stack
  • Python
  • Flask
  • JavaScript
  • jQuery
  • Sass
  • Gulp
Source on GitHub

Roomz

Rakuten Hackathon finalist

Book meeting rooms from your phone

Roomz is an iOS app for checking, booking, and canceling meeting rooms at Rakuten's Tokyo office. It shows room availability in real time through the Microsoft Office 365 Outlook API, so people could grab a free room on the spot and the company didn't need to pay for a third-party booking tool.

Tech stack
  • Swift
  • iOS
  • Xcode
  • Office 365 Outlook API
Source on GitHub

Tolen

One Traction AR/VR Hackathon finalist

An augmented reality restaurant review market

Photos on review sites only show part of a restaurant, and you can't tell how big a dish really is. Tolen lets you experience a restaurant before you go: browse a clickable menu that shows each dish as a hologram, and look around the dining room in a 360-degree video. Restaurants can show off their best-rated dishes, and diners know what to expect.

Tech stack
  • Swift
  • iOS
  • Augmented reality
  • 360° video
Source on GitHub

BUSale

Boston University

A college marketplace built on Instagram

BUSale is a free marketplace for college students. Anyone can sell a used item or a service by posting it on Instagram with #busale in the caption, and buyers browse and buy those listings on the BUSale website. It pulls posts through the Instagram API into an MVC web app written in PHP with a MySQL database.

Tech stack
  • PHP
  • MySQL
  • MVC
  • Instagram API

Finding Information Framework

Boston University School of Medicine

Evidence-based medicine, on iOS

FIF was the first iOS app built for the Boston University School of Medicine. It's a medical education app that helps students practice finding the resources behind evidence-based medicine. I designed it with Balsamiq wireframes, built it in Objective-C, beta tested it through TestFlight, and shipped it to the App Store.

Tech stack
  • Objective-C
  • iOS
  • Xcode
  • Balsamiq
  • TestFlight
Product page

Get In Touch

Marika Lam

Let's connect

  • marikaleelam@gmail.com
  • linkedin.com/in/marikalam
  • github.com/marikalam

I'm open to new projects, freelance work and collaborations. Have an idea or need a hand building something? Send me a message below or email me directly at marikaleelam@gmail.com.