YangYu Song, Full-stack Developer in Singapore, Singapore
YangYu Song

Full-stack Developer in Singapore, Singapore

Member since June 11, 2021
As a full-stack developer focusing on the back end, Yangyu has more than six years of professional experience with fast-paced startups and big companies with remote teams such as Grab, Shopee, and PayPal. He is proficient in Golang and Ruby on Rails, and he cares about code quality, readability, and maintainability.
YangYu is now available for hire


  • Shopee
    Algorithms, Go, Memcached, Clean Code, Clean Architecture, MySQL, Grafana...
  • Grab
    Go, ScyllaDB, Amazon Web Services (AWS), SQL, REST, Microservices
  • 90 Seconds
    Ruby on Rails (RoR), GraphQL, AWS, Ruby, SQL, REST



Singapore, Singapore



Preferred Environment

Ubuntu, MacOS, Slack, Mattermost, Git, GitHub, GitLab, Jenkins, GitLab CI/CD

The most amazing...

...thing I've migrated is the cache layer of a 200,000 QPS service, without any noticeable extra latencies in the API.


  • Senior Software Engineer

    2020 - PRESENT
    • Maintains core user APIs, maintaining cache update pipeline, take on-duty issues, handling 500k peak QPS.
    • Lead features related to User Address. Talk to PM & relaetd stake holders about product features; design system architecture.
    • Built up proper test cares, lint rules & report the test coverage on Gitlab; write proper documentations about our & others' system; setup standard for how to write API documentation within our team.
    Technologies: Algorithms, Go, Memcached, Clean Code, Clean Architecture, MySQL, Grafana, Prometheus, Apache Kafka
  • Senior Software Engineer

    2019 - 2020
    • Took full ownership of auto-billing service for advertisers, starting the whole service from scratch and running well on production.
    • Took ownership of our service infrastructure and load test internal system. Managed the auto-scaling policy on AWS, ensuring the service met its SLA under a given load.
    • Took on the call duties. Answered colleagues' questions, debugged issues, created Jira tickets based on user feedback, and improved monitoring alerts based on incidents.
    Technologies: Go, ScyllaDB, Amazon Web Services (AWS), SQL, REST, Microservices
  • Senior Software Engineer

    2018 - 2018
    90 Seconds
    • Designed and implemented GraphQL API endpoint for different apps. Furthermore, I also improved the GraphQL subscription in the GraphQL-Ruby repository.
    • Upgraded the monolith website from Rails 3.2 to 4.2.
    • Synchronized with the product team to identify the real problem, managed tasks for other back-end engineers, and set up proper Git workflow with Jira and GitLab.
    Technologies: Ruby on Rails (RoR), GraphQL, AWS, Ruby, SQL, REST
  • Software Engineer

    2015 - 2017
    • Developed a customer review module using React and Redux.
    • Built the basic product and voucher logic in Solidus.
    • Designed the product attributes for the listing and pushed them to Elasticsearch via CronJob.
    Technologies: Rails Engines, React, Redux, RailsAdmin, SQL, REST


  • Ad Auto Billing Pipeline

    An auto-billing pipeline was implemented in Golang, which Grab uses to bill the merchants who use the GrabAds. The pipeline would aggregate the ingested ad display data and create the billing records by calling the corresponding services.

    I built the entire pipeline from scratch, using AWS Lambda and CloudWatch. It has a test coverage of more than 70%, runs daily for all Southeast Asia countries where Grab operates.

  • Customer Review Listing Page

    This customer review listing page has a Ruby on Rails back end that services customer cases, allowing customers to post reviews independently. The front end is a React component, initially placed on a Magento eCommerce website.

    The company then migrated the website to be Ruby on Rails serving the back-end API and React front end. This review component was then integrated with the other components as a complete, single-page application.

  • Music Notebook

    A notebook for people to upload music and share comments.

    I'm in charge of building the whole back end, including providing RESTful API, supporting live events via ActionCable, processing the uploaded music via Google Cloud Functions, and monitoring via Datadog.

    It's deployed on Heroku, running in the lowest pricing tier, such as the hobby tier.


  • Languages

    Go, Ruby, HTML, SQL, JavaScript, CSS, Java, GraphQL
  • Frameworks

    Ruby on Rails (RoR), Redux
  • Paradigms

    REST, Microservices, Clean Code, Clean Architecture
  • Tools

    Git, Jira, Jenkins, GitLab CI/CD, Grafana
  • Platforms

    Amazon Web Services (AWS), Ubuntu, Apache Kafka, Google Cloud Engine, Heroku
  • Storage

    Databases, Memcached, PostgreSQL, ScyllaDB, MySQL
  • Other

    Algorithms, Optimization, Migration, Distributed Systems, Cloud Computing, Deep Learning, Concurrency, AWS, Compilers, Prometheus
  • Libraries/APIs

    Rails Engines, React


  • Master's Degree in Computer Science
    2016 - 2018
    National University of Singapore - Singapore
  • Bachelor's Degree in Computer Engineering
    2010 - 2014
    National University of Singapore - Singapore


  • Parallel, Concurrent, and Distributed Programming in Java
  • Deep Learning
    JULY 2018 - PRESENT
  • Architecting with Google Compute Engine
    JULY 2018 - PRESENT

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