Cao Qin

Experience

Where I’ve worked

1. NCS Group

   Software Engineer · Java / Spring

   • Built Java and Spring services on AWS for national e-services, using MyBatis and Oracle behind REST APIs and nightly batch workflows, under reliability, security and data-governance requirements.
   • Owned a nightly ingestion pipeline end to end: integrated an external HTTP API with JWT token-expiry handling, split retrieval into failure-isolated chunks, and applied bounded exponential-backoff retries.
   • Protected Oracle persistence from duplicate writes through pre-insert reconciliation and a composite key, then calculated and surfaced risk indicators for the user-facing application.
   • Generated convention-based CSV outputs in S3, implemented copy-then-delete archival after a successful SFTP upload, and standardized data-exchange contracts across seven government systems.
   • Worked with product owners and non-technical stakeholders to turn regulatory and operational needs into reliable services, balancing correctness, maintainability and delivery timelines.

   • Java
   • Spring
   • AWS
   • Oracle
   • MyBatis
   • REST
   • JWT
   • S3
   • SFTP
   • Batch

   Jul 2023 — Jan 2025

2. Notewise

   Software Engineer · Android / Java, iOS / Swift

   • Core contributor on a small team building a cross-platform note-taking product now serving over one million monthly users, delivering production features on both Android/Java and iOS/Swift.
   • Owned a synchronized editing experience end to end, resolving state, geometry, view transforms and rendering issues under interactive performance constraints.
   • Built reusable interaction and direct in-canvas text-editing models, partnering with design and product to turn nuanced requirements into maintainable production behavior.

   • Java
   • Android
   • Swift
   • iOS

   Feb 2025 — Jan 2026

3. NCS Group

   Software Engineer Intern · Python / Flask

   • Developed Python and Flask backend services integrating a Microsoft Azure OCR service to validate documents and extract structured data for downstream processing.
   • Built Python/Selenium tools for internal workflows, Excel VBA spreadsheet automation, and Windows batch and shell scripts for automated testing.

   • Python
   • Flask
   • Azure
   • Selenium

   Jan 2022 — Jun 2022

Stack

What I work with

Languages

Java, Python, JavaScript/TypeScript, Swift

Backend & data

Spring, MyBatis, REST/HTTP APIs, JWT, Flask, Oracle, Postgres, SQL, batch processing

Cloud & reliability

AWS (EC2, S3, CloudWatch), SFTP, retries, idempotency, CI/CD, production debugging

Engineering

System design, distributed-systems foundations, testing, cross-functional delivery

Selected work

PourNote

Independent product engineer · 2026 – present

I took a local-first SwiftUI iOS product from definition through implementation, App Store release, subscriptions, analytics, localization and iteration — alone. Keeping data on the device was a deliberate trade-off: it gave up cross-device sync and server-side recovery in exchange for privacy and a very small operational surface for a solo project.

The server-side piece is a TypeScript Supabase Edge Function handling in-app feedback, with JSON request validation, Postgres-backed server-side rate limiting and Resend email integration. First released 13 May 2026; around 200 monthly active users and a first paying customer by September 2026.

• Swift
• SwiftUI
• TypeScript
• Supabase
• Edge Functions
• Postgres
• RevenueCat
• Firebase

PourNote on the App Store↗

Also on the App Store

• Triday To-Do ↗

  Yesterday · Today · Tomorrow

  A minimal task list built around three days at a time, so planning stays a short horizon rather than an ever-growing backlog.

• Aftertap ↗

  Everything happens 0.3s late

  A timing game where every input lands 0.3 seconds behind, so you aim where the target will be instead of where it is.

About

A bit about me