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Develops across the UI, backend server, and data layer, delivering end-to-end products (web applications and mobile apps) with robust offline/local-first or secure backend-backed architectures. Leads engineering work from domain/service/data design through testing and CI/CD, building systems that integrate modern web/mobile tooling with APIs, databases, authentication, and reliable deployments.…

Yifan Liu

Full Stack Developer, Software Engineer, Back-End Developer, +2

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Develops across the UI, backend server, and data layer, delivering end-to-end products (web applications and mobile apps) with robust offline/local-first or secure backend-backed architectures. Leads engineering work from domain/service/data design through testing and CI/CD, building systems that integrate modern web/mobile tooling with APIs, databases, authentication, and reliable deployments.…

Available to hire

Develops across the UI, backend server, and data layer, delivering end-to-end products (web applications and mobile apps) with robust offline/local-first or secure backend-backed architectures.
Leads engineering work from domain/service/data design through testing and CI/CD, building systems that integrate modern web/mobile tooling with APIs, databases, authentication, and reliable deployments.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Intermediate

Intermediate

Work Experience

Front-end developer and integration owner at Anti-Phishing Assistant (Capstone project, University of Sydney)

June 2, 2023 - Present

Built an Android app for an external client that watches Gmail, calls, and Zoom meetings and warns users about phishing or deepfakes. Defined and maintained the app’s shared data pipeline so that multiple capture modules and background services could feed the interface without tight coupling. Implemented UI using Jetpack Compose based on Figma prototypes and delivered in an agile team over 12 weeks with weekly client reviews.

at Lexigo (iOS language learning app + backend service)

September 2, 2020 - Present

Developed an iOS language learning app (Swift/SwiftUI) with Duolingo-style quiz review and an AI conversation partner. Implemented an LLM-backed backend that answers word lookups and builds learner vocabulary sets based on goals discovered through conversation. Added real-time streaming over a WebSocket connection with server-side checks and session termination reporting. Used SwiftUI with a local GRDB database for offline review; ensured in-app purchases are verified server-side and callbacks can’t be double-charged.

at TSAT (Goal planner web app)

February 2, 2019 - May 1, 2025

Built a local-first to-do planner that turns long-term goals into linked tasks and generates each day’s list. Runs entirely in the browser with no server storing user data, using a TypeScript domain/service/persistence architecture. Shipped as an installable offline-capable PWA backed by IndexedDB (Dexie). Added optional cloud sync where a Cloudflare Worker exchanges OAuth tokens while user data remains on the user’s own drive. Implemented end-to-end testing and multiple automated workflows to ensure reliability on every pull request.