Portrait of Jay (CheHao) Liu

Jay (CheHao) Liu

Software Engineer. Backend systems, data platforms and applied AI.

Open to opportunities · Brisbane or remoteNo sponsorship needed (485)

About

I’ve spent 6+ years building backend systems, from chatbot and NLU products to distributed services and data platforms. At AmazingTalker I led a 3–4 person engineering team; at Sourect I owned backend architecture for a B2B MVP.

Now I apply the same discipline to LLMs, RAG and coding agents, while completing a Master of IT at QUT. I’m looking for backend or applied AI roles.

Work rights

I’m in Brisbane on a student visa with work rights now. After my Master finishes in Nov 2026 I move to a Temporary Graduate visa (subclass 485) with full, unrestricted work rights, so no employer sponsorship is needed in the near term.

Case studies

  1. 2021 – 2023

    Data warehouse & developer platform AmazingTalker

    Marketing and product teams waited on engineers for every report. I built a BigQuery warehouse with self-service reporting, and an Nx platform that deploys only the services a change affects.

    • 30% → 5% of sprint time spent on reporting
    • 3 days to ship a new data API, down from about a week
    How it was built
    Given
    Business data, advertising data and in-house tracking lived in separate systems. Marketing and product teams depended on engineering work to prepare reports.
    Warehouse
    BigQuery with Datastream CDC, Airflow and dbt, plus Metabase for self-service reporting. It unified business data with GA, Meta, Google Ads, TikTok and in-house tracking.
    Platform
    An Nx monorepo with a service generator, shared libraries and CI/CD that built and deployed only affected services to EKS. Product teams adopted it to decouple services from the main app.
  2. 2021 – 2023

    Teacher ranking & video pipeline AmazingTalker

    New sales took about 20 minutes to reach teacher rankings. I replaced full batch recomputation with event-driven, per-teacher updates, and launched the short-video pipeline.

    • 20 → 2 min for new sales to reach rankings
    • −60% ranking API latency, 500 → 200 ms
    • 1,000+ video transcoding jobs per day
    How it was built
    Ranking
    Elasticsearch scoring and Redis sorted sets per locale. Event-driven updates recalculated individual teachers instead of the full batch.
    Video
    S3, SQS fan-out, ffmpeg on Lambda and HLS via CloudFront. Playback tracking fed teacher ranking and video recommendations.
  3. 2023 – 2025

    RAG-based knowledge system Freelance

    Staff needed to query private documents in plain language without content leaking between users. I built a RAG pipeline that answers only from permission-scoped context.

    • Per-user data isolation
    • Automated ingestion
    • Vector search
    How it was built
    Method
    Automated ingestion, chunking and embedding into a vector store, with an LLM answering only from retrieved, permission-scoped context.
    Decision
    Per-user data isolation was part of the design from the start, so security held up as the document set and user base grew.

Experience

  1. 2026 – Now

    Full Stack Engineer QUT Industry Project

    Primary developer in a six-person team building an on-premise government AI proof of concept.

    • Express
    • PostgreSQL
    • Python
  2. 2024 – 2025

    Contract Software Engineer (Part-time) Sourect

    Owned the backend of a B2B garment-manufacturing MVP, including Stripe payments and an artwork validation and vectorisation pipeline.

    • NestJS
    • Prisma
    • PostgreSQL
    • Stripe
  3. 2023 – 2025

    Full Stack Engineer Freelance

    Permission-scoped RAG, layout-preserving translation for 100+ page financial reports, and an iGaming CRM used by dozens of operations staff.

    • Go
    • RAG
    • Python
    • FastAPI
  4. 2021 – 2023

    Senior Backend Engineer AmazingTalker

    Led a 3–4 person team across data, ranking and service-platform work. Built an onboarding project used by ~10 engineers, typically shipping to production within 3 days.

    • BigQuery
    • Airflow
    • dbt
    • Elasticsearch
    • Redis
    • AWS
  5. 2019 – 2021

    Backend Engineer WEI-PO

    Removed Redis KEYS scans and queued settlement, cutting API time from 400 to 50 ms. Built an idempotent wallet load-tested to 2,000+ QPS.

    • RabbitMQ
    • Redis
    • CI/CD
2 earlier roles, 2017 – 2019
  1. 2018 – 2019

    Backend Engineer Pentium Network Technology

    Integrated CDN and FQDN resources across AWS, Alibaba Cloud, Tencent Cloud and GCP; built chatbot and workflow automation with Kafka.

  2. 2017 – 2018

    Backend Engineer Lingtelli

    Built the company’s chatbot product for Facebook and LINE and its natural-language-understanding engine.

Projects

  1. RAGcat

    Upload PDFs, review the extracted passages and embed a support chatbot on your own site. Every answer cites the document and page it came from.

    • Python
    • FastAPI
    • React
    • Bedrock
    • ECS Fargate
    • TypeScript
    • CloudFront
    • DynamoDB
    • SQS
    • Lambda
    • S3 Vectors
    • Cognito
    • Valkey
  2. Codex Cage

    Takes a GitHub or Linear issue to a pull request inside a disposable sandbox. Tests, a secret scan and an independent review must pass first.

    • TypeScript
    • Docker
    • Codex
    • CI/CD
  3. Strobe Assistant

    A conversational assistant for your own posts and photos. Chat stays separate from asynchronous media work, and mutations need explicit permission.

    • Python
    • AWS Bedrock
    • S3 Vectors
    • SQS / Lambda
    • MCP
    • DynamoDB
    • ECS Fargate
    • EventBridge
    • Cognito
    • WebSocket
  4. Knowledge Compiler

    Turns scattered notes into a knowledge base. Every proposed change carries its source evidence, and you decide what gets applied.

    • TypeScript
    • OpenAI Agents SDK
    • RAG
    • PostgreSQL
    • pgvector
    • Express
    • React
    • ParadeDB
  5. AI Meeting Management Platform

    An on-premise government proof of concept from a QUT industry project, turning recordings into draft minutes and action items.

    • Node.js
    • PostgreSQL
    • Redis Streams
    • Whisper
    • Llama 3
    • Python
    • SSE
    More

    Built for the Department of Science and Technology (DOST), Philippines, with me as the primary developer in a Brisbane-based team of six. Whisper transcribes recordings and a local Llama 3 model drafts minutes and action items for staff to review on the client’s infrastructure. A transactional outbox and Redis Streams provide durable job dispatch across Node.js and Python workers; SSE reports progress without blocking the API.

Education

  1. 2025 – 2026

    Master of Information Technology QUT, Brisbane

    Expected Nov 2026.

  2. 2011 – 2015

    Bachelor of Computer Science NTUST, Taiwan

Skills

Languages
Go, Python, TypeScript / Node.js, Ruby, C#, NestJS, Express, FastAPI, React, REST / GraphQL
Data
PostgreSQL, MySQL, Redis, Elasticsearch, BigQuery, dbt, Airflow, CDC, RabbitMQ, Kafka
Cloud
AWS, GCP, Docker, Kubernetes (EKS), GitHub Actions, New Relic, Nx
AI
RAG, vector databases, Llama 3, Whisper, Amazon Bedrock, agentic workflows, MCP / ACP, Claude Code

Contact

Open to senior backend and applied AI roles, in Brisbane or remote. The fastest way to reach me is email.

Email
[email protected]
LinkedIn
linkedin.com/in/jhowliu
GitHub
github.com/jhowliu
Résumé
PDF, one page