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Duncan Leo

Hey there! I’m a software engineer based in Singapore.

In June 2015, I set up Undertide with my friend Jurvis, where we built Nebulo and Harmany.

I’ve worked at Buuuk and UserTesting, and am currently working at Taskade.

My Work

DPI Calculator

App to calculate density

GAON Chart

Music charts in Korea

mrtdown

Public transit monitoring in SG

Nebulo

Beautiful haze reports

Readit

Private Reddit client

TrafficCam

Road imagery for Singapore

Experience

Undertide Jun 2015 - Present
Co-Founder Singapore
  • Undertide is a development studio building full-stack web and mobile apps.
  • As Co-Founder, I led technical development across projects using React, Next.js, Kotlin, Go, Swift, and PostgreSQL.
    • Delivered production apps for clients, from feature scoping to deployment.
    • Mentored junior engineers, including high school interns.
    • Notable projects:
      • Harmany: cross-platform music link sharing app (Android, Go, PostgreSQL)
      • DawnSlideshow: Slideshow app supporting Live Photos and videos (SwiftUI)
      • Courtney Barnett Archive: Digital content archive site
Taskade Aug 2023 - Present
Senior Software Engineer (Tech Lead) Singapore
  • Taskade is a collaborative productivity platform for real-time tasks, notes and AI workflows used by thousands of customers.
  • As a tech lead, I led engineering initiatives, AI integrations, and architecture planning across the product.
    • Integrated GPT-4o and other LLMs into AI tools, including a writing assistant and automation engine.
    • Enhanced user workflows and enabled LLM-triggered actions
    • Designed a dynamic query-based table view; shipped an automation system now used in over 10,000 workflows.
    • Cut build times by 50% and reduced bugs through GraphQL codegen integration
    • Refactored legacy backend systems to improve response times and maintainability.
Taskade Nov 2019 - Aug 2023
Software Engineer Singapore
  • Prior to my promotion to Senior Software Engineer (Tech Lead), I contributed across the full stack, focusing on UI performance, backend services and developer experience.
UserTesting Mar 2016 - Mar 2017
Software Engineering Intern Mountain View, CA
  • UserTesting is a leading platform for remote usability testing and customer feedback.
    • As a Software Engineering Intern, I built an internal KPI dashboard and Electron-based tracking tools to support engineering operations.
    • Automated QA workflows with Selenium and Calabash, improving test coverage and reducing manual testing.
buUuk Aug 2015 - Oct 2015
Android Intern Singapore
  • Developed onboarding flows and custom UI animations for Android apps.